06494G_Frontmatter

ASM Handbook�

Volume 13ACorrosion:

Fundamentals, Testing, and Protection

Prepared under the direction of theASM International Handbook Committee

Stephen D. Cramer and Bernard S. Covino, Jr., Volume Editors

Charles Moosbrugger, Project EditorBonnie R. Sanders, Manager of Production

Gayle J. Anton, Editorial AssistantNancy Hrivnak, Jill Kinson, and Carol Polakowski, Production Editors

Kathryn Muldoon, Production AssistantScott D. Henry, Assistant Director of Technical Publications

William W. Scott, Jr., Director of Technical Publications

Editorial AssistanceElizabeth MarquardHeather Lampman

Mary Jane RiddlebaughBeverly Musgrove

Materials Park, Ohio 44073-0002www.asminternational.org

© 2003 ASM International. All Rights Reserved.ASM Handbook, Volume 13A Corrosion: Fundamentals, Testing, and Protection (#06494G)

www.asminternational.org

Copyright � 2003by

ASM International�All rights reserved

No part of this book may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic,mechanical, photocopying, recording, or otherwise, without the written permission of the copyright owner.

First printing, October 2003

This book is a collective effort involving hundreds of technical specialists. It brings together a wealth of information fromworldwide sources to help scientists, engineers, and technicians solve current and long-range problems.

Great care is taken in the compilation and production of this Volume, but it should be made clear that NO WARRANTIES,EXPRESS OR IMPLIED, INCLUDING, WITHOUT LIMITATION, WARRANTIES OF MERCHANTABILITY OR FITNESS FORA PARTICULAR PURPOSE, ARE GIVEN IN CONNECTION WITH THIS PUBLICATION. Although this information is believed tobe accurate by ASM, ASM cannot guarantee that favorable results will be obtained from the use of this publication alone. This publicationis intended for use by persons having technical skill, at their sole discretion and risk. Since the conditions of product or material use areoutside of ASM’s control, ASM assumes no liability or obligation in connection with any use of this information. No claim of any kind,whether as to products or information in this publication, and whether or not based on negligence, shall be greater in amount than thepurchase price of this product or publication in respect of which damages are claimed. THE REMEDY HEREBY PROVIDED SHALLBE THE EXCLUSIVE AND SOLE REMEDY OF BUYER, AND IN NO EVENT SHALL EITHER PARTY BE LIABLE FOR SPE-CIAL, INDIRECT OR CONSEQUENTIAL DAMAGES WHETHER OR NOT CAUSED BY OR RESULTING FROM THE NEGLI-GENCE OF SUCH PARTY. As with any material, evaluation of the material under end-use conditions prior to specification is essential.Therefore, specific testing under actual conditions is recommended.

Nothing contained in this book shall be construed as a grant of any right of manufacture, sale, use, or reproduction, inconnection with any method, process, apparatus, product, composition, or system, whether or not covered by letters patent, copyright,or trademark, and nothing contained in this book shall be construed as a defense against any alleged infringement of letters patent,copyright, or trademark, or as a defense against liability for such infringement.

Comments, criticisms, and suggestions are invited, and should be forwarded to ASM International.

Library of Congress Cataloging-in-Publication Data

ASM International

ASM HandbookIncludes bibliographical references and indexes

Contents: v.1. Properties and selection—irons, steels, and high-performance alloys—v.2. Properties and selection—nonferrous alloysand special-purpose materials—[etc.]—v.21. Composites

1. Metals—Handbooks, manuals, etc. 2. Metal-work—Handbooks, manuals, etc. I. ASM International. Handbook Committee.II. Metals Handbook.

TA459.M43 1990 620.1�6 90-115SAN: 204-7586

ISBN: 0-87170-705-5

ASM International�Materials Park, OH 44073-0002


Printed in the United States of America

Multiple copy reprints of individual articles are available from Technical Department, ASM International.



iii

Foreword

ASM International is pleased to publish ASM Handbook, Volume 13A, Corrosion: Fundamentals,Testing, and Protection, the first book in a two-volume revision of the landmark 1987 Metals Handbook,9th Edition volume on corrosion. ASM Handbook, Volume 13A has been completely revised and up-dated to address the needs of ASM International members and the global technical community forcurrent and comprehensive information on corrosion principles, evaluation techniques, and protectionmethods. Advances in material science and corrosion technologies since the 1987 Corrosion volumewas published have lessened some of the costs and degradation caused by corrosion. However, thesystems that society relies on have increased in complexity during this time, so corrosion can have morefar-reaching effects. Corrosion remains a multibillion-dollar problem that confronts nearly every engi-neer in every industry.

ASM International is indebted to the Co-Chairs and Editors of this Handbook, Stephen D. Cramerand Bernard S. Covino, Jr., who had the vision and the drive to undertake the huge effort to update andrevise the 1987 Corrosion volume. ASM Handbook, Volume 13A is the first fruit of their efforts; theyare also leading the project to complete ASM Handbook, Volume 13B, Corrosion: Materials, Environ-ments, and Industries, scheduled to publish in 2005. The Editors have done an outstanding job inorganizing the project, in recruiting renowned experts to oversee sections and to write or revise articles,and in reviewing every manuscript. We are pleased with their vision to recruit authors from Canada,Mexico, France, Germany, United Kingdom, Poland, Japan, India, and Australia, as well as from theUnited States. This diverse community of volunteers, sharing their knowledge and experience, makethis Volume truly an international effort.

We thank the authors and reviewers of the 1987 Corrosion volume, which at the time was the largest,most comprehensive volume on a single topic ever published by ASM. This new edition builds uponthat groundbreaking project. Thanks also go to the ASM Handbook Committee for their oversight andinvolvement, and to the ASM editorial staff for their tireless efforts.

We are especially grateful to the nearly 200 authors and reviewers listed in the next several pages.Their willingness to invest their time and effort and to share their knowledge and experience by writing,rewriting, and reviewing articles has made this Handbook an outstanding source of information.

Donald R. MuzykaPresidentASM International

Stanley C. TheobaldManaging DirectorASM International



iv

Policy on Units of Measure

By a resolution of its Board of Trustees, ASM International has adoptedthe practice of publishing data in both metric and customary U.S. units ofmeasure. In preparing this Handbook, the editors have attempted to presentdata in metric units based primarily on Systeme International d’Unites (SI),with secondary mention of the corresponding values in customary U.S.units. The decision to use SI as the primary system of units was based onthe aforementioned resolution of the Board of Trustees and the widespreaduse of metric units throughout the world.

For the most part, numerical engineering data in the text and in tablesare presented in SI-based units with the customary U.S. equivalents inparentheses (text) or adjoining columns (tables). For example, pressure,stress, and strength are shown both in SI units, which are pascals (Pa) witha suitable prefix, and in customary U.S. units, which are pounds per squareinch (psi). To save space, large values of psi have been converted to kipsper square inch (ksi), where 1 ksi � 1000 psi. The metric tonne (kg �103) has sometimes been shown in megagrams (Mg). Some strictly sci-entific data are presented in SI units only.

To clarify some illustrations, only one set of units is presented on art-work. References in the accompanying text to data in the illustrations arepresented in both SI-based and customary U.S. units. On graphs and charts,grids corresponding to SI-based units usually appear along the left andbottom edges. Where appropriate, corresponding customary U.S. units ap-pear along the top and right edges.

Data pertaining to a specification published by a specification-writinggroup may be given in only the units used in that specification or in dualunits, depending on the nature of the data. For example, the typical yieldstrength of steel sheet made to a specification written in customary U.S.

units would be presented in dual units, but the sheet thickness specified inthat specification might be presented only in inches.

Data obtained according to standardized test methods for which the stan-dard recommends a particular system of units are presented in the units ofthat system. Wherever feasible, equivalent units are also presented. Somestatistical data may also be presented in only the original units used in theanalysis.

Conversions and rounding have been done in accordance with IEEE/ASTM SI-10, with attention given to the number of significant digits inthe original data. For example, an annealing temperature of 1570 �F con-tains three significant digits. In this case, the equivalent temperature wouldbe given as 855 �C; the exact conversion to 854.44 �C would not be ap-propriate. For an invariant physical phenomenon that occurs at a precisetemperature (such as the melting of pure silver), it would be appropriateto report the temperature as 961.93 �C or 1763.5 �F. In some instances(especially in tables and data compilations), temperature values in �C and�F are alternatives rather than conversions.

The policy of units of measure in this Handbook contains several ex-ceptions to strict conformance to IEEE/ASTM SI-10; in each instance, theexception has been made in an effort to improve the clarity of the Hand-book. The most notable exception is the use of g/cm3 rather than kg/m3 asthe unit of measure for density (mass per unit volume).

SI practice requires that only one virgule (diagonal) appear in unitsformed by combination of several basic units. Therefore, all of the unitspreceding the virgule are in the numerator and all units following thevirgule are in the denominator of the expression; no parentheses are re-quired to prevent ambiguity.



between environmental degradation, of which corrosion is a major element,and service or service life, with cost determining the point of balance. Costsare determined not in the spare confines of a material and its environmentbut in a complex landscape defined by technical, economic, social, envi-ronmental, health, safety, legal, and consumer constraints. This is illus-trated by the experience of a Portland, OR Water Bureau engineer workingto make way for a new light rail line along city streets (Ref 2):

. . . Construction conflicts are anticipated . . . , but day-to-day con-struction also alters the original design and corrosion control schemeof existing installations. As development occurs and utilities weaveand cross, coatings are damaged, pipes are shorted, wires are cut, andtest stations always seem to disappear . . . Work had to be sequencedand paced to minimize traffic interference . . . Environmental regu-lators were classifying the pavement as an engineered cap for brown-field and other contaminated areas . . . Utilities responded by char-acterizing the roadway as a constantly opening and closing zipperbecause we continually construct there . . . Corrosion control methodsfor urban areas must be designed for installation and operation in acongested environment that is constantly changing.This Handbook is organized into six major sections addressing corrosion

fundamentals, testing, and protection.The first Section, “Fundamentals of Corrosion,” covers the theory of

aqueous and gaseous corrosion from the thermodynamic and kinetic per-spectives. It presents the principles of electrochemistry, the mechanismsof corrosion processes, and the methods for measuring corrosion rates inaqueous, molten salt, liquid metals, and gaseous environments. It intro-duces geochemical modeling as a means for characterizing and understand-ing corrosion in complex environments. While corrosion is usually asso-ciated with the environmental degradation of a material, this Section alsodescribes ways in which corrosion is used for constructive or beneficialpurposes.

The second Section, “Forms of Corrosion,” describes how to recognizethe different types of corrosion and the forces that influence them. It ad-dresses uniform corrosion, localized corrosion, metallurgically influencedcorrosion, mechanically assisted corrosion, environmentally inducedcracking, and microbiologically influenced corrosion. The Section intro-duces the complex processes of wear-corrosion interactions that acceleratematerial deterioration at rates greater than those resulting from wear pro-cesses or corrosion processes alone.

The third Section, “Corrosion Testing and Evaluation,” describes theplanning of corrosion tests, evaluation of test results, laboratory corrosiontesting, simulated service testing, and in-service techniques for damagedetection and monitoring. It concludes by describing standard methods andpractices for evaluating the various forms of corrosion.

The fourth Section, “Methods of Corrosion Protection,” begins by dis-cussing as a baseline the corrosion resistance of bulk materials. The Sectioncontinues with methods of corrosion protection, including surface treat-ments and conversion coatings, ceramic, glass and oxide coatings, metalcoatings, coatings and linings, electrochemical corrosion control methods,and corrosion inhibitors.

The fifth Section, “Designing for Corrosion Control and Prevention,”continues the theme of the fourth Section from the perspective of materials

v

Preface

The direct cost of corrosion in the United States was estimated to be$276 billion annually for 1998, or 3.1% of the 1998 U.S. gross domesticproduct of $8.79 trillion (Ref 1). Of the industry sectors analyzed, utilitiesand transportation experienced the largest costs. The largest investment incorrosion control and protection strategies was in protective organic coat-ings. Indirect costs of corrosion, including lost productivity and corrosion-related overhead and taxes, when averaged over industry sectors, wereroughly equal to or greater than the direct costs. In some cases they weresubstantially greater. For example, indirect corrosion costs related to theU.S. bridge infrastructure were estimated to be more than 10 times the $8.3billion direct cost from bridge corrosion damage. Additional informationis available in the article “Direct Costs of Corrosion in the United States”in this Volume.

ASM Handbook, Volume 13A, Corrosion: Fundamentals, Testing, andProtection, is the first volume in a two-volume update, revision, and ex-pansion of Corrosion, Volume 13 of the ninth edition Metals Handbook,published in 1987. The second volume—ASM Handbook, Volume 13B,Corrosion: Materials, Environments, and Industries—is to be publishedin 2005. The purpose of these two volumes is to represent the current stateof knowledge in the field of corrosion and to provide a perspective onfuture trends in the field. Metals remain the major focus of the Handbook,but nonmetallic materials occupy a more prominent position that reflectstheir wide and effective use to solve problems of corrosion. Wet or aqueouscorrosion remains the major focus, but dry or gaseous corrosion is dis-cussed more fully, reflecting the increased importance of processes at el-evated and high temperatures.

ASM Handbook, Volume 13A recognizes the global nature of corrosionresearch and practice and the international level of corrosion activities andinteractions required to provide cost-effective, safe, and environmentallysound solutions to materials problems in chemically aggressive environ-ments. Twenty percent of the articles in Volume 13A did not appear in the1987 Handbook. Authors from more than ten countries have contributedto Volume 13A. The table of contents has been translated into Spanish,French, Russian, Japanese, and Chinese to make the Handbook accessibleto a diverse audience. Extensive references provide a road map to thecorrosion literature and are augmented by Selected References that are asource of additional information.

Information technology has changed dramatically since 1987, and themost significant occurrence has been the development of the Internet asan information resource. In response, ASM International has made thecontents of this Handbook and others in the ASM Handbook series avail-able on the Web. This Handbook also provides a list, current at the timeof publication, of significant data sources and of major national, interna-tional, academic, and government corrosion organizations and institutionsthat are accessible on the Web.

Corrosion is described by well-known laws of thermodynamics, kinet-ics, and electrochemistry. The many variables that influence the behaviorof a material in its environment can lead to a wide and complex range ofperformance, from the benign to the catastrophic. Understanding andavoiding detrimental corrosion is an interdisciplinary effort requiringknowledge of chemistry, electrochemistry, materials, engineering, andstructures. All applications of engineered materials pivot on the fulcrum



selection and equipment design. Corrosion control is an economic processas well as a technical process, and this Section discusses corrosion eco-nomic calculations, predictive modeling for structure service life, and areview of corrosion costs in the United States.

The sixth Section, “Tools for the Corrosionist,” covers topics that arecomplementary to corrosion fundamentals, testing, and protection. It is anew addition to the Handbook. The topics include conventions and defi-nitions in corrosion and oxidation, applications of modern analytical in-struments in corrosion, materials science, statistics, and informationsources and databases.

Other useful Handbook contents include the “Glossary of Terms,” con-taining definitions of corrosion, electrochemistry, and materials terms com-mon to corrosion and defined in the literature of ISO, ASTM, and NACEInternational. The “Corrosion Rate Conversion” Section includes conver-sions in both nomograph and tabular form. The metric conversion guidefeatures conversion factors for common units and includes SI prefixes.Finally, “Abbreviations and Symbols” provides a key to common acro-nyms, abbreviations, and symbols.

The six Sections in the Handbook are divided into several subsections.These subsections were organized and written under the leadership of thefollowing individuals (listed in alphabetical order):

Chairperson Subsection Title

Vinod S. Agarwala In-Service Techniques for Damage Detection and MonitoringRudolph G. Buchheit Surface Treatments and Conversion CoatingsBernard S. Covino, Jr. Laboratory Corrosion TestingBruce D. Craig Environmentally Induced CrackingStephen D. Cramer Simulated Service Testing

Metal CoatingsCorrosion InhibitorsTools for the Corrosionist

Marek Danielewski Fundamentals of Gaseous CorrosionStephen C. Dexter Microbiologically Influenced CorrosionPeter Elliott Designing for Corrosion Control and ProtectionGerald Frankel Metallurgically Influenced CorrosionWilliam A. Glaeser Mechanically Assisted DegradationRussell D. Kane Uniform CorrosionCarl E. Locke, Jr. Electrochemical Corrosion Control MethodsPhilippe Marcus Fundamentals of Corrosion ThermodynamicsPaul M. Natishan Corrosion Resistance of Bulk MaterialsBopinder S. Phull Evaluating Forms of CorrosionVilupanur A. Ravi Ceramic, Glass, and Oxide CoatingsPierre R. Roberge Planning Corrosion Tests and Evaluating ResultsJohn R. Scully Fundamentals of Aqueous Corrosion KineticsSusan Smialowska Localized CorrosionKenneth B. Tator Coatings and LiningsPeter F. Tortorelli Fundamentals Applied to Specific EnvironmentsIan Wright Mechanically Assisted DegradationMargaret Ziomek-Moroz Fundamentals of Corrosion for Constructive Purposes

These talented and dedicated individuals generously devoted considerabletime to the preparation of this Handbook. They were joined in this effortby more than 120 authors who contributed their expertise and creativity ina collaborative venture to write or revise the articles and by more than 200reviewers and 5 translators. These volunteers built on the contributions ofearlier Handbook authors and reviewers who provided the solid foundationon which the present Handbook rests.

For articles revised from the previous edition, the contribution of theseauthors is acknowledged at the end of articles. This location in no waydiminishes their contribution or our gratitude. Those responsible for the

current revision are named after the title. The variation in the amount ofrevision is broad. The many completely new articles presented no chal-lenge for attribution, but assigning fair credit for revised articles was moreproblematic. The choice of presenting authors’ names without commentor with the qualifier “Revised by” is solely the responsibility of the ASMstaff.

We thank ASM International and the ASM staff for their skilled supportand valued expertise in the production of this Handbook. In particular, wethank Charles Moosbrugger, Gayle Anton, and Scott Henry for their en-couragement, tactful diplomacy, and many discussions, plus, we shouldadd, their wistful forbearance as deadlines came and went. The AlbanyResearch Center, U.S. Department of Energy, gave us support and flexi-bility in our assignments to participate in this project and we are mostgrateful. In particular, we thank our supervisors Jeffrey A. Hawk and Cyn-thia P. Dogan, who were most gracious and generous with their encour-agement throughout the project.

We close with these thoughtful words from T.R.B. (Tom) Watson, pres-ident of NACE International, 1964–65, author of Why Metals Corrode,and corrosion leader (Ref 3):

Mighty ships upon the ocean, suffer from severe corrosion.Even those that stay at dockside, are rapidly becoming oxide.

Alas, that piling in the sea is mostly Fe2O3.And where the ocean meets the shore, you’ll find there’s Fe3O4.’Cause when the wind is salt and gusty, things are getting awfullyrusty.

We can measure it, we can test it, we can halt it or arrest it;We can scrape it and weigh it; we can coat it or spray it;We can examine and dissect it; we can cathodically protect it.We can pick it up and drop it, but heaven knows we’ll never stop it.

So here’s to rust, no doubt about it; most of us would starve withoutit.

That said, given the thermodynamic, kinetic, and economic principles atwork in our world, corrosion will not stop. This Handbook helps show ushow to live with it.

REFERENCES

1. G. H. Koch, M. P. H. Brongers, N. G. Thompson, Y. P. Virmani, andJ. H. Payer, Corrosion Cost and Preventive Strategies in the UnitedStates, FHWA-RD-01–156, Federal Highway Administration, U.S. De-partment of Transportation, Washington D.C., 773 pp., March 2002.

2. Stu Greenberger, Underground Water Utilities – Crowded and Com-plex, Mater. Perform., Vol. 41, No. 7, July 2002, p. 8.

3. “Rust’s a Must,” by T.R.B. Watson, poem reprinted by permission ofJean Watson; also reprinted in The Boatowner’s Guide to Corrosion,by Everett Collier, Ragged Mountain Press, Camden ME, 2001. Oneline of the poem was modified for the purposes of this publication.

Stephen D. CramerBernard S. Covino, Jr.U.S. Department of EnergyAlbany Research Center

vi



vii

Officers and Trustees of ASM International (2002–2003)

Donald R. MuzykaPresident and TrusteeSpecial Metals Corporation (retired)

Robert C. Tucker, Jr.Vice President and TrusteeThe Tucker Group, LLC

Gordon H. GeigerImmediate Past President and TrusteeUniversity of Arizona

John W. PridgeonTreasurerAllvac

TrusteesReza Abbaschian

University of FloridaKathleen B. Alexander

Los Alamos National LaboratoryRodney R. Boyer

Boeing Commercial Airplane Group

Subi DindaDaimlerChrysler Corporation

R.G. (Gil) GillilandOak Ridge National Laboratory

Andrew R. NicollSulzer Metco (US) Inc.

Richard D. Sisson, Jr.Worcester Polytechnic Institute

George F. Vander VoortBuehler Ltd.

Lawrence C. WagnerTexas Instruments Inc.

Members of the ASM Handbook Committee (2002–2003)

Henry E. Fairman(Chair 2002–; Member 1993–)Cincinnati Metallurgical Consultants

Jeffrey A. Hawk(Vice Chair 2002–; Member 1997–)U.S. Department of Energy

David E. Alman (2002–)U.S. Department of Energy

Bruce P. Bardes (1993–)Cincinnati Metallurgical Consultants

Lichun Leigh Chen (2002–)Engineered Materials Solutions

Craig V. Darragh (1989–)The Timken Company

Larry D. Hanke (1994–)Materials Evaluation and Engineering Inc.

Dennis D. Huffman (1982–)The Timken Company (retired)

Dwight Janoff (1995–)FMC Corporation

Kent L. Johnson (1999–)Engineering Systems Inc.

Paul J. Kovach (1995–)Stress Engineering Services Inc.

Donald R. Lesuer (1999–)Lawrence Livermore National Laboratory

Huimin Liu (1999–)Ford Motor Company

William L. Mankins (1989–)Metallurgical Services Inc.

Srikanth Raghunathan (1999–)Nanomat Inc.

Karl P. Staudhammer (1997–)Los Alamos National Laboratory

Kenneth B. Tator (1991–)KTA-Tator Inc.

George F. Vander Voort (1997–)Buehler Ltd.

George A. Wildridge (2000–)Borg Warner Morse TEC Corporation

Previous Chairs of the ASM Handbook Committee

R.J. Austin(1992–1994) (Member 1984–)

L.B. Case(1931–1933) (Member 1927–1933)

T.D. Cooper(1984–1986) (Member 1981–1986)

C.V. Darragh(1999–2002) (Member 1989–)

E.O. Dixon(1952–1954) (Member 1947–1955)

R.L. Dowdell(1938–1939) (Member 1935–1939)

M.M. Gauthier(1997–1998) (Member 1990–)

J.P. Gill(1937) (Member 1934–1937)

J.D. Graham(1966–1968) (Member 1961–1970)

J.F. Harper(1923–1926) (Member 1923–1926)

C.H. Herty, Jr.(1934–1936) (Member 1930–1936)

D.D. Huffman(1986–1990) (Member 1982–)

J.B. Johnson(1948–1951) (Member 1944–1951)

L.J. Korb(1983) (Member 1978–1983)

R.W.E. Leiter(1962–1963) (Member 1955–1958,1960–1964)

G.V. Luerssen(1943–1947) (Member 1942–1947)

G.N. Maniar(1979–1980) (Member 1974–1980)

W.L. Mankins(1994–1997) (Member 1989–)

J.L. McCall(1982) (Member 1977–1982)

W.J. Merten(1927–1930) (Member 1923–1933)

D.L. Olson(1990–1992) (Member 1982–1988,1989–1992)

N.E. Promisel(1955–1961) (Member 1954–1963)

G.J. Shubat(1973–1975) (Member 1966–1975)

W.A. Stadtler(1969–1972) (Member 1962–1972)

R. Ward(1976–1978) (Member 1972–1978)

M.G.H. Wells(1981) (Member 1976–1981)

D.J. Wright(1964–1965) (Member 1959–1967)

Stanley C. TheobaldSecretary and Managing DirectorASM International



Stephen D. CramerAlbany Research Center, U.S. Departmentof Energy

Chester DacresDacco Sciences Inc.

Marek DanielewskiAGH University of Science and Technology(Krakow)

Guy DavisDacco Sciences Inc.

Sheldon DeanDean Corrosion Technology

Stephen C. DexterUniversity of Delaware

David DreisingerUniversity of British Columbia

James C. EarthmanUniversity of California, Irvine

Peter ElliottCorrosion & Materials Consultancy Inc.

E. EscalanteNational Institute of Science andTechnology (Retired)

Allen D. FellerIntel Corporation

Paul B. FischerIntel Corporation

Gerald FrankelThe Ohio State University

James FritzTechnical Marketing Resources

Aleksander GilUniversity of Mining & Metallurgy(Krakow)

William A. GlaeserBattelle Columbus

Richard D. GranataFlorida Atlantic University

Zbigniew GrzesikThe Ohio State University

Harvey HackNorthrop Grumman Corp.

Harry R. HansonBay Engineering

Christopher HahinIllinois Department of Transportation

Robert H. HeidersbachDr. Rust, Inc.

Gordon R. HolcombAlbany Research Center, U.S. Departmentof Energy

Kyle T. HoneycuttAnalytical Processes/Engineered Solutions,Inc.

Francois HuetUniversite Pierre et Marie Curie

Anthony E. HughesCommonwealth Scientific & IndustrialResearch Organisation

Iwao IwasakiUniversity of Minnesota

Vijay K. JainIndian Institute of Technology

Barnie P. JonesOregon Department of Transportation

Russell JonesBattelle Pacific Northwest Laboratories

Robert M. KainConsultant

Russell D. KaneInterCorr International Incorporated

Farida KasumzadeProgress Casting Group, Inc.

Robert G. KellyUniversity of Virginia

Robert J. KlassenRoyal Military College of Canada

Gerhardus H. KochCC Technologies Laboratories, Inc.

David KolmanLos Alamos National Laboratory

Lorrie KrebsDacco Sciences Inc.

Jerome KrugerJohns Hopkins University

Kyei-Sing KwongAlbany Research Center, U.S. Departmentof Energy

Tom LangillAmerican Galvanizers Association

Ralph W. LeonardGalvoInfo Center

viii

Authors and Contributors

Thomas A. AdlerAlbany Research Center, U.S. Departmentof Energy

M.K. Adler FlittonIdaho National Engineering andEnvironmental Laboratory

Vinod S. AgarwalaNaval Air Systems Command

Tatyana N. AndryushchenkoIntel Corporation

Peggy J. ArpsUniversity of California, Irvine

Denise AylorNaval Surface Warfare Center

Robert BaboianRB Corrosion Service

Christopher C. BerndtState University of New York, Stony Brook

Marita L. BerndtBrookhaven National Laboratory

Bennett P. BoffardiBennett P. Boffardi and Associates, Inc.

Stuart BondTWI Ltd.

Alan BraySystems and Materials ResearchConsultancy

Michiel P.H. BrongersCC Technologies Laboratories, Inc.

Craig L. BrooksAnalytical Processes/Engineered Solutions,Inc.

Rudolph G. BuchheitThe Ohio State University

Kenneth C. CadienIntel Corporation

Richard E. ChinnAlbany Research Center, U.S. Departmentof Energy

Sean G. CorcoranVirginia Tech University

Bernard S. Covino, Jr.Albany Research Center, U.S. Departmentof Energy

Bruce D. CraigMetCorr



Brenda J. LittleNaval Research laboratory

Carl E. Locke, Jr.University of Kansas

Florian MansfeldUniversity of Southern California

Philippe MarcusEcole Nationale Superieure de Chimie deParis

Richard MartinBJ Unichem Chemical Services

Steven A. MatthesAlbany Research Center, U.S. Departmentof Energy

Thomas B. MillsAnalytical Processes/Engineered Solutions,Inc.

Anne E. MillerIntel Corporation

Ted MooneyFinishing.com. Inc.

Kevin M. MooreEnergetics, Inc.

James MoranAlcoa Technical Center

Makoto NishimuraOak (Nippon) Co., Ltd.

Paul M. NatishanNaval Research Laboratory

James NoelUniversity of Western Ontario

Ricardo P. NogueiraUniversite Pierre et Marie Curie

Bernard NormandUniversite Pierre et Marie Curie

Kevin OgleUsinor Research

Joe H. PayerCase Western Reserve University

Ignacio PerezNavair

Bopinder S. PhullConsultant

Jimmy D. PoindexterBJ Unichem Chemical Services

Scott A. Prost-DomaskyAnalytical Processes/Engineered Solutions,Inc.

Elie ProtopopoffEcole Nationale Superieure de Chimie deParis

Robert A. RappThe Ohio State University

Vilupanur A. RaviCalifornia Polytechnic Institute

James C. RawersAlbany Research Center, U.S. Departmentof Energy

Raul B. RebakLawrence Livermore National Laboratory

Izumi N. Reed

Wayne ReitzNorth Dakota State University

Anne Robbins

Pierre R. RobergeRoyal Military College of Canada

John R. ScullyUniversity of Virginia

A.J. SedriksOffice of Naval Research

E. Bud SenkowskiKTA-Tator Inc.

Sadiq ShahWestern Illinois University

Barbara ShawPennsylvania State University

David ShiflerNaval Surface Warfare Center

David W. ShoesmithUniversity of Western Ontario

David C. SilvermanArgentum Solutions, Inc.

Raymund SingletonSingleton Corporation

Susan SmialowskaThe Ohio State University

Jack SnodgrassAlcoa Technical Center

Narasi SridharSouthwest Research Institute

Kurt H. SternNaval Research Laboratory

James StottCAPCIS Ltd.

Hideaki TakahashiHokkaido University

Hisasi TakenoutiUniversite Pierre et Marie Curie

Kenneth B. TatorKTA-Tator Inc.

Neil G. ThompsonCC Technologies Laboratories, Inc.

Garth R. Tingey

Jack TinneaTinnea Associates

Peter F. TortorelliOak Ridge National Laboratory

Joseph H. TylczakAlbany Research Center, U.S. Departmentof Energy

Kunigahalli VasanthNaval Surface Warfare Center

Lucien VelevaCINVESTAB-IPN

Y. Paul VirmaniFederal Highway Administration

Mark C. WilliamsNational Energy Technology Laboratory,U.S. Department of Energy

Charles F. WindischPacific Northwest National Laboratory

Michael WolpersHenkel KgaA

Ian WrightOak Ridge National Laboratories

Lietai YangSouthwest Research Institute

Te-Lin YauTe-Lin Yau Consultancy

Steven Y. Yu3M

Małgorzata Ziomek-MorozAlbany Research Center, U.S. Departmentof Energy

ix



Fred IennaShell Global Solutions

Tom JackNova Research and Technology Center

Dwight JanoffFMC Technologies

Mark JaworoskiUnited Tchnologies Research Center

Kent. L. JohnsonEngineering Systems Incorporated

Joanne Jones-MeehanU.S. Naval Research Laboratory

Dwaine L. KlarstromHaynes International Inc.

R. KomanduriOklahoma State University

Paul J. KovachStress Engineering Services Incorporated

Virginia M. LesserOregon State University

Donald R. LesuerLawrence Livermore National Laboratory

George J. LicinaStructural Integrity Assoc.

Eugene L. LieningDow Chemical Company

McIntyre R. LouthanSavannah River Tech Center

Kenneth C. LudemaUniversity of Michigan

Stan P. LynchAeronautical and Maritime ResearchLaboratory (Australia)

Gregory MakarWestvaco

William L. MankinsMetallurgical Services Incorporated

Ron E. MarrelliConoco Phillips

George MatzkaninTRI/NTIAC

Stephen MaxwellCommercial Microbiology

Gerald H. MeierUniversity of Pittsburgh

Bert MonizDuPont Company

Neville R. MoodySandia Corporation

John J. MooreColorado School of Mines

Bill MullinsU.S. Army

John N. MurrayMurray’s et al.

Robert M. O’BrienUniversity of Oregon

Tom O’KeefeUniversity of Missouri (Rolla)

Sankara PapavinasamCANMET

Antoine PourbaixCebelcor

Srinivasan RaghavanUniversity of Arizona

Srikanth K. RaghunathanNanomat Incorporated

Robert A. RappThe Ohio State University

Anthony P. ReynoldsUniversity of South Carolina

Joseph L. RosePennsylvania State University

Brian J. SaldanhaDuPont Company

John R. ScullyUniversity of Virginia

Ken-ichi ShimizuKeio University

John A. ShreifelsGeorge Mason University

Robert SilbersteinNorthrop Grumman Integrated Systems

Theresa C. SimpsonBethlehem Steel Corp.

Ron SkaboCH2M Hill

Karl P. StaudhammerLos Alamos National Laboratory

Jean StockardUniversity of Oregon

x

Reviewers

Robert S. AlwittBoundary Technologies, Inc.

David E. AlmanAlbany Research Center, U.S. Dept. ofEnergy

S.V. BabuClarkson University

Sean BrossiaSouthwest Research Institute

Monica M. ChauviereExxonMobil Research and Engineering

Lichun Leigh ChenEngineered Materials Solutions

O.V. ChettyIndian Institute of Technology

T.C. ChevrotTotalFinaElf

Jim CrumSpecial Metals Corporation

Craig V. DarraghThe Timken Company

Larry DeLashmitBlair Rubber

Jim DivineChemMet, Ltd.

Barry DuganZinc Corp. of America

Henry E. FairmanCincinnati Metallurgical Consultants

Robert Frankenthal

Benjamin FultzBechtel Corp.

Martin GagneNoranda, Inc.

Edward GhaliLaval University

Larry D. HankeMaterials Evaluation & EngineeringIncorporated

Jeffrey A. HawkAlbany Research Center, U.S. Dept. ofEnergy

Krista HeidersbachChevronTexaco

Dennis D. HuffmanThe Timken Company



Glenn StonerUniversity of Virginia

James StrathmanPortland State University

S.R. TaylorUniversity of Virginia

Herman TerrynVrije Universiteit Brussel

Wen-Ta TsaiNational Cheng Kung University

Vilayanur V. ViswanathanPacific Northwest National laboratory

J. von FraunhoferUniversity of Maryland

Robert WoodsZaclon, Inc.

John F. YoungJ.F. Young International Inc.

Gregory Ke ZhangTeck Cominco Metals

xi



Kinetics of Aqueous Corrosion Processes .. . . . . . . . . . . . . . . . . . . . .44Activation Control of Corrosion .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .45Mass Transport Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .47Influence of Corrosion Product Deposits . . . . . . . . . . . . . . . . . . . . . . .49Kinetics of Corrosion of Passive Metals .. . . . . . . . . . . . . . . . . . . . . .49

Aqueous Corrosion Reaction Mechanisms ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .52Fundamental Aspects of Electrode Kinetics .. . . . . . . . . . . . . . . . . .52Electrode Kinetics near the Corrosion Potential . . . . . . . . . . . . . . .54Mechanisms of Cathodic Processes .. . . . . . . . . . . . . . . . . . . . . . . . . . . .56Mechanisms of Anodic Processes .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .56

Passivity .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .61General Aspects .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .61Kinetics of Passivity .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .62Thermodynamics of Passivity .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .62Kinetics of Passivity .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .62Nature of the Passive Film ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .63Passive-Film Formation and Dissolution .. . . . . . . . . . . . . . . . . . . . . .64Breakdown of the Passive Film ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .65

Methods for Determining Aqueous Corrosion Reaction Rates .. . . . . . . . . .68Electrochemical Methods .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .68Electrode Reaction Thermodynamics and Kinetics in

Corrosion .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .68Electrochemical Methods for the Study of Uniform

Corrosion: Polarization Methods .. . . . . . . . . . . . . . . . . . . . . . . . . . . .70Polarization Resistance Methods .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .71Electrochemical Impedance Methods .. . . . . . . . . . . . . . . . . . . . . . . . . .72Frequency Modulation Methods .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .73Electrochemical Noise Resistance .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .74Electrochemical Methods for the Study of Galvanic

Corrosion Rates .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .75Electrochemical Methods for the Definition of

Conditions Where Corrosion Rates Are High ... . . . . . . . . . . .76Evaluation of Intergranular Corrosion Rates .. . . . . . . . . . . . . . . . . .79Electrochemical Methods for Evaluation of Corrosion

Rates under Paints .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .80Nonelectrochemical Methods That Determine

Cumulative Mass Loss .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .80

Fundamentals of Gaseous CorrosionIntroduction to Fundamentals of Corrosion in Gases .. . . . . . . . . . . . . . . . . . . . .87

Fundamental Data .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .87Thermodynamics of Gaseous Corrosion .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .90

Fundamental Data .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .90Free Energy of Reaction .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .90Richardson-Jeffes Diagrams ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .92Phase Sequence in the Multilayered Scale .. . . . . . . . . . . . . . . . . . . .93Kellogg Diagrams ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .94

xii

Contents

Fundamentals of Corrosion ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Introduction to the Fundamentals of Corrosion .. . . . . . . . . . . . . . . . . . . . . . . . . . . . 3Thermodynamics .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3Kinetics .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3Gaseous Corrosion .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4Constructive Uses of Corrosion .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4Conclusions .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Fundamentals of Corrosion ThermodynamicsIntroduction to Fundamentals of Corrosion Thermodynamics .. . . . . . . . . . . 5

Electrochemical Reactions .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5Molten Salt Corrosion Thermodynamics .. . . . . . . . . . . . . . . . . . . . . . . 5Geochemical Modeling .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Electrode Processes .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6Electrode Reactions .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Electrode Potentials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8Thermodynamics of Chemical Equilibria .. . . . . . . . . . . . . . . . . . . . . . 8Reactions in Aqueous Solutions .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8Thermodynamics of Electrochemical Equilibria .. . . . . . . . . . . . .10Cell Potentials and the Electromotive Force Series .. . . . . . . . . .11

Potential Measurements with Reference Electrodes .. . . . . . . . . . . . . . . . . . . . . .13The Three-Electrode Device .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13Electrode Selection Characteristics .. . . . . . . . . . . . . . . . . . . . . . . . . . . . .13Operating Conditions for Reference Electrodes .. . . . . . . . . . . . . .15

Potential versus pH (Pourbaix) Diagrams ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17Calculation and Construction of E-pH Diagrams ... . . . . . . . . . .18Practical Use of E-pH Diagrams ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22E-pH Diagrams for Ternary Systems ... . . . . . . . . . . . . . . . . . . . . . . . . .23E-pH Diagrams for High-Temperature Aqueous Solutions ..24E-pH Diagrams for Adsorbed Species .. . . . . . . . . . . . . . . . . . . . . . . . .27

Molten Salt Corrosion Thermodynamics .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .31Thermodynamics of Cells . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .31Electrodes for Molten Salts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .31Thermodynamics of Molten Salt Corrosion .. . . . . . . . . . . . . . . . . . .32

Geochemical Modeling .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .34History of Geochemical Modeling .. . . . . . . . . . . . . . . . . . . . . . . . . . . . .35Principles of Geochemical Modeling .. . . . . . . . . . . . . . . . . . . . . . . . . .35Limitations in Geochemical Modeling .. . . . . . . . . . . . . . . . . . . . . . . . .36Describing Equilibrium ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .37Applications of Geochemical Modeling to Corrosion .. . . . . . .37Geochemical Modeling Features .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .39

Fundamentals of Aqueous Corrosion KineticsKinetics of Aqueous Corrosion .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .42

Basis of Corrosion Reactions .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .42Thermodynamic Basis for Corrosion .. . . . . . . . . . . . . . . . . . . . . . . . . .43



Determination of Partial Pressures of Gas Mixtures .. . . . . . . . .94Partial Pressures of Volatile Oxidation Products .. . . . . . . . . . . . .95

Kinetics of Gaseous Corrosion Processes .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .97Defect Structure of Oxide .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .97Solid-State Diffusion .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .98Oxide Texture .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101Oxidation Kinetics .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101Thin-Film Mechanisms ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102

Gaseous Corrosion Mechanisms ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106Properties of Scales .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106Stresses in Scales .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107Stress Relief . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108Sulfidation .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112Metal Dusting .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113Chlorine Corrosion .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113Summary Outline of Alloy Oxidation .. . . . . . . . . . . . . . . . . . . . . . . 113

Methods for Measuring Gaseous Corrosion Rates .. . . . . . . . . . . . . . . . . . . . . . 115Discontinuous Methods .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115Continuous Methods .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115

Fundamentals Applied to Specific EnvironmentsCorrosion in Molten Salts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117

Phase Stability and Salt Chemistry .. . . . . . . . . . . . . . . . . . . . . . . . . . . 117Electrochemistry and Fused Salt Corrosion .. . . . . . . . . . . . . . . . . 119Scale Fluxing: A Hot Corrosion Mechanism ... . . . . . . . . . . . . . 120Consequences of Salt Chemistry on Corrosion .. . . . . . . . . . . . . 121Conclusions .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122

Corrosion by Molten Nitrates, Nitrites, and Fluorides .. . . . . . . . . . . . . . . . . 124Test Methods .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124Purification .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124Nitrates/Nitrites .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124Fluorides .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125Conclusions .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 128

Corrosion by Liquid Metals .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129Corrosion Reactions in Liquid-Metal Environments .. . . . . . 129Considerations in Materials Selection .. . . . . . . . . . . . . . . . . . . . . . . 133

Fundamentals of Corrosion for Constructive PurposesIntroduction to Corrosion for Constructive Purposes .. . . . . . . . . . . . . . . . . . . 135

Reversible Cell Potential . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135Irreversible Cell Potential . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 136

Electropolishing .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139Electrical Circuits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139Anodic Processes .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139Selection of Electrolytes .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 140Kinetics of Electropolishing .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 140Properties of Electropolished Surfaces .. . . . . . . . . . . . . . . . . . . . . . . 141

Electrochemical Machining .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143Electrochemical Machining System ... . . . . . . . . . . . . . . . . . . . . . . . . 143Theory of ECM .... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 144Metal-Removal Rate .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 145Interelectrode Gap ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 146Electrolyte Conductivity .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 146Process Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 146Electrolytes .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 146Workpiece Shape Prediction .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 147Tool Design .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 148Integrated Approach for Tool Design in ECM .... . . . . . . . . . . 148Process Capabilities and Limitations .. . . . . . . . . . . . . . . . . . . . . . . . . 150Application Examples .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 150

Electrochemical Allied Processes .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153Electrochemical Deburring .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153Electrochemical Deep-Hole Drilling .. . . . . . . . . . . . . . . . . . . . . . . . . 154Pulse Electrochemical Machining .. . . . . . . . . . . . . . . . . . . . . . . . . . . . 155

Electrochemical Hybrid Processes .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157Electrochemical Grinding .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157The ECG Machine Tool .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 158Process Characteristics .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 158Applications .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159

Electrochemical Refining ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 160Electrochemical Cell . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 160Metals Purified ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 160Principles of the Electrochemical Reactions .. . . . . . . . . . . . . . . . 160Physical Properties of Electrochemical Cells . . . . . . . . . . . . . . . . 161Engineering Considerations in the Refining Process .. . . . . . 161

Chemical-Mechanical Planarization for Semiconductors .. . . . . . . . . . . . . . 164History .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 164Chemical-Mechanical Planarization Overview ... . . . . . . . . . . . 164Chemistry of Metal CMP ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 164Electrochemical Theories and Methods in CMP ... . . . . . . . . . 166Uncontrolled Corrosion—Chemically Induced Defects .. . . 167Conclusions .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 168

Anodes for Batteries .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 170Constructive versus Destructive Corrosion in Batteries .. . . 170Constructive Corrosion as Part of Power Generation .. . . . . . 171Constructive Corrosion as Part of Battery

Manufacturing .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 175Destructive Corrosion .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 175Conclusions .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 176

Fuel Cells . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 178Performance .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 178Fuel-Cell Technology Overview ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . 179

Forms of Corrosion ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 187

Introduction to Forms of Corrosion .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 189Uniform Corrosion .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 189Localized Corrosion .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 189Metallurgically Influenced Corrosion .. . . . . . . . . . . . . . . . . . . . . . . . 189Mechanically Assisted Degradation .. . . . . . . . . . . . . . . . . . . . . . . . . . 189Environmentally Induced Cracking .. . . . . . . . . . . . . . . . . . . . . . . . . . 189Microbiologically Influenced Corrosion .. . . . . . . . . . . . . . . . . . . . . 189

Uniform CorrosionAqueous Corrosion .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 190

Effect of pH (Acidity) .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 190Oxidizing Power (Electrochemical Potential) . . . . . . . . . . . . . . . . 192Temperature and Heat Transfer .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 193Velocity and Fluid Movement .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 193Component Concentration and Composition .. . . . . . . . . . . . . . . 194

Atmospheric Corrosion .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 196Elements of the Process .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 196Atmospheric Parameters and Their Influence .. . . . . . . . . . . . . . . 198Air Chemistry and Principal Pollutants Inducing

Corrosion .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 199Thermodynamics of Atmospheric Corrosion and Use of

Pourbaix Diagrams ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 200Models for Prediction of Atmospheric Corrosion .. . . . . . . . . . 203Atmospheric Corrosion and Precipitation Runoff from

Corroded Metals .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 204Biologically Influenced Atmospheric Corrosion .. . . . . . . . . . . 205

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Trends in Atmospheric Corrosion Research andMethods .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 205

Galvanic Corrosion .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 210Galvanic Series .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 210Polarization .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 210Area, Distance, and Geometric Effects .. . . . . . . . . . . . . . . . . . . . . . 210Modes of Attack .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 211Predicting Galvanic Corrosion .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 211Performance of Alloy Groupings .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 211Methods of Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 213

Stray-Current Corrosion .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 214Sources of Stray Currents .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 214Prevention of Stray-Current Corrosion .. . . . . . . . . . . . . . . . . . . . . . 215

Molten Salt Corrosion .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 216Mechanisms of Molten Salt Corrosion .. . . . . . . . . . . . . . . . . . . . . . 216Types of Molten Salts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 217Prevention of Molten Salt Corrosion .. . . . . . . . . . . . . . . . . . . . . . . . . 218

Liquid Metal Corrosion .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 220Experience in Systems Exposed to Liquid Metals .. . . . . . . . . 220Forms of Liquid-Metal Corrosion .. . . . . . . . . . . . . . . . . . . . . . . . . . . . 220Safety Considerations .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 223

High-Temperature Gaseous Corrosion .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 228High-Temperature Oxidation .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 230Sulfidation .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 230Carburization .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 231Other Forms of High-Temperature Corrosion .. . . . . . . . . . . . . . 232

Localized CorrosionPitting Corrosion .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 236

Phenomenology of Pitting Corrosion .. . . . . . . . . . . . . . . . . . . . . . . . 236Stages of Pitting .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 239

Crevice Corrosion .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 242Critical Factors .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 242Selected Examples .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 244Testing .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 245Prevention or Mitigation of Crevice Corrosion .. . . . . . . . . . . . . 245

Filiform Corrosion .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 248Occurrence of Attack .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 248Mechanism of Attack .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 249Filiform Corrosion of Steels .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 249Tests for Filiform Corrosion .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 249Filiform Corrosion of Coated Aluminum and

Magnesium ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 250Prevention of Filiform Corrosion .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 254

Metallurgically Influenced CorrosionIntroduction to Metallurgically Influenced Corrosion .. . . . . . . . . . . . . . . . . . 257

Stainless Steel and Nickel Alloys .. . . . . . . . . . . . . . . . . . . . . . . . . . . . 257Aluminum ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 257Factors Influencing Corrosion .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 257

Effects of Metallurgical Variables on Aqueous Corrosion .. . . . . . . . . . . . . 258Fundamentals of Pure Metals, Impure Metals, and

Alloys .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 258Influence on Corrosion .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 260

Effects of Metallurgical Variables on the Corrosion of StainlessSteels .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 266

Austenitic Stainless Steels .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 266Ferritic Stainless Steels .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 268Duplex Stainless Steels .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 271High-Performance Stainless Steels .. . . . . . . . . . . . . . . . . . . . . . . . . . . 272

Effects of Metallurgical Variables on the Corrosion of AluminumAlloys .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 275

Effect of Constituent Alloys on Pitting Corrosion ofAluminum ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 275

1xxx Series Alloys .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2752xxx Series Alloys .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2753xxx Series Alloys .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2764xxx Series Alloys .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2765xxx Series Alloys .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2766xxx Series Alloys .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2767xxx Series Alloys .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 277

Effects of Metallurgical Variables on the Corrosion of High-NickelAlloys .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 279

Heat-Resistant Alloys .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 279Effect of Chemical Composition on the Corrosion

Behavior of Nickel Corrosion-Resistant Alloys .. . . . . . . . . 279Factors Affecting the Corrosion Behavior of Nickel-Base

Alloys .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 281Changes in Microstructure .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 281Conclusions .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 285

Effects of Metallurgical Variables on Dealloying Corrosion .. . . . . . . . . . 287Dealloying in Aqueous Environments .. . . . . . . . . . . . . . . . . . . . . . . 287The Critical Potential . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 289Below the Critical Potential . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 289Morphology Above the Critical Potential . . . . . . . . . . . . . . . . . . . . 289Mechanisms ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 289

Corrosion of Carbon Steel Weldments .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 294Influence of Weld Microstructure .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 294Residual Stress .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 294Geometrical Factors .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 294Preferential Heat-Affected Zone Corrosion .. . . . . . . . . . . . . . . . . 294Preferential Weld Metal Corrosion .. . . . . . . . . . . . . . . . . . . . . . . . . . . 295Galvanic Corrosion .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 295Mitigation of Preferential Weldment Corrosion .. . . . . . . . . . . . 295Industrial Case Studies .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 296Stress-Corrosion Cracking .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 297

Corrosion of Stainless Steel Weldments .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 301Metallurgical Factors .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 301Corrosion of Austenitic Stainless Steel Weldments .. . . . . . . . 301Corrosion of Ferritic Stainless Steel Weldments .. . . . . . . . . . . 311Corrosion of Duplex Stainless Steel Weldments .. . . . . . . . . . . 313

Corrosion of Nonferrous Alloy Weldments .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 317Metallurgical Factors .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 317Corrosion of Aluminum Alloy Weldments .. . . . . . . . . . . . . . . . . . 317Corrosion of Titanium Alloy Weldments .. . . . . . . . . . . . . . . . . . . . 318Corrosion of Tantalum Alloy Weldments .. . . . . . . . . . . . . . . . . . . 319Corrosion of Nickel and High-Nickel Alloy Weldments .. . 320

Mechanically Assisted DegradationForms of Mechanically Assisted Degradation .. . . . . . . . . . . . . . . . . . . . . . . . . . . 322

Erosion .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 322Fretting Corrosion .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 324Fretting Fatigue .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 325Cavitation Erosion and Water Drop Impingement .. . . . . . . . . 326Corrosion Fatigue .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 328

Aqueous Corrosion-Wear Interactions .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 331Methods of Wear Measurements .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 331Model of Corrosive Wear .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 332Polarization Curve Measurements under Abrasion .. . . . . . . . 332Effect of Galvanic Interactions on Flotation .. . . . . . . . . . . . . . . . 332Mechanism of Electrochemical Interaction .. . . . . . . . . . . . . . . . . 333Relative Significance of Corrosion and Abrasion in

Wear .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 333

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Galvanic Interactions in Multielectrode Systems ... . . . . . . . . . 334Case History on Material Selection for Grinding Balls .. . . 335

Gaseous Corrosion Wear Interactions .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 338Mechanisms ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 338Measurement .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 342Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 343

Environmentally Induced CrackingIntroduction to Environmentally Induced Cracking .. . . . . . . . . . . . . . . . . . . . 345Stress-Corrosion Cracking .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 346

The Phenomenon of SCC ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 346Overview of SCC Mechanisms ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 347Controlling Parameters .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 348Important Fracture Features .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 349Phenomenology of Crack Initiation Processes .. . . . . . . . . . . . . . 349Crack Initiation Mechanisms ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 350Phenomenology of Crack Propagation Processes .. . . . . . . . . . 351Crack Propagation Mechanisms ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . 360

Hydrogen Damage ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 367Classification of Hydrogen Processes .. . . . . . . . . . . . . . . . . . . . . . . . 367Theories for Hydrogen Damage ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . 368Hydrogen Damage in Iron-Base Alloys .. . . . . . . . . . . . . . . . . . . . . 370Nickel Alloys .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 374Aluminum Alloys .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 375Copper Alloys .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 375Titanium Alloys .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 376Zirconium Alloys .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 377Vanadium, Niobium, Tantalum and Their Alloys .. . . . . . . . . . 378Intermetallic Compounds .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 379

Liquid Metal Induced Embrittlement .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 381Mechanisms of Embrittlement .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 382Role of Liquid in Crack Propagation .. . . . . . . . . . . . . . . . . . . . . . . . 383Occurrence of LMIE ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 383Effects of Metallurgical, Mechanical, and Physical

Factors .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 385Fatigue in Liquid Metal Environments .. . . . . . . . . . . . . . . . . . . . . . 387Decrease or Elimination of LMIE Susceptibility .. . . . . . . . . . . 387Embrittlement of Nonferrous Metals and Alloys .. . . . . . . . . . . 387Embrittlement of Ferrous Metals and Alloys .. . . . . . . . . . . . . . . 388

Solid Metal Induced Embrittlement .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 393Characteristics of SMIE ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 393Investigations of SMIE ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 394Delayed Failure and Mechanism of SMIE ... . . . . . . . . . . . . . . . . 394

Microbiologically Influenced CorrosionMicrobiologically Influenced Corrosion .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 398

General Characteristics of Microbes .. . . . . . . . . . . . . . . . . . . . . . . . . 399Organisms Involved in Biological Corrosion .. . . . . . . . . . . . . . . 399Formation of Biofilms ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 400General Mechanisms by Which Biological Organisms

Influence Corrosion .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 402Industries Affected .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 404Microbiologically Influenced Corrosion of Various

Materials .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 404Testing for Microbiologically Influenced Corrosion .. . . . . . . 409Prevention of MIC ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 410Further Reading .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 413

Corrosion Testing and Evaluation ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 417

Introduction to Corrosion Testing and Evaluation .. . . . . . . . . . . . . . . . . . . . . . 419Planning Corrosion Tests and Evaluating Results . . . . . . . . . . . 419Laboratory Corrosion Testing .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 419

Simulated Service Corrosion Testing .. . . . . . . . . . . . . . . . . . . . . . . . 419In-Service Techniques for Damage Detection and

Monitoring .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 419Evaluating Forms of Corrosion .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 419

Planning Corrosion Tests and Evaluating ResultsDesigning, Planning, and Preparing Corrosion Tests .. . . . . . . . . . . . . . . . . . . 420

Test Objectives and Conditions .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 420Design of Experiments .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 421Examples of Experimental Designs Applied to Corrosion

Testing .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 423Statistical Interpretation of Corrosion Test Results . . . . . . . . . . . . . . . . . . . . . . 425

Complexity of Test Conditions .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 425Mechanistic Aspects .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 426Probabilistic Aspects .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 426Statistical Analysis .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 429

Modeling Corrosion Processes .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 430Mechanistic Models .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 430Risk-Based Models .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 438Knowledge Models .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 442

Laboratory Corrosion TestsElectrochemical Methods of Corrosion Testing .. . . . . . . . . . . . . . . . . . . . . . . . . 446

Fundamentals .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 446Preparing an Electrochemical Polarization Experiment .. . . 447No-Applied-Signal Tests .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 449Small-Signal Polarization Tests .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 451Large-Signal Polarization Tests .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 455Scanning Electrode Techniques .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 459Miscellaneous Techniques .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 460

Immersion Testing .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 463Total Immersion .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 463Autoclave Tests .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 465Partial Immersion to Vapor Phase .. . . . . . . . . . . . . . . . . . . . . . . . . . . . 466Intermittent Immersion .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 466Specimen Preparation Duration of Tests .. . . . . . . . . . . . . . . . . . . . . 467Calculation of Corrosion Rate .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 468Reporting the Data .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 468

Cabinet Testing .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 470Applications and Use of Salt Spray (Fog) Testing .. . . . . . . . . 470Static Atmosphere Condition Salt Spray (Fog) Tests .. . . . . . 473Cyclic and Other Atmosphere Condition Salt Spray

(Fog) Tests .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 474Combining Weathering (Light Exposure Apparatus)

and Salt Spray (Fog) Type Corrosion Tests .. . . . . . . . . . . . . . 474Test Specimen Procedures for Salt Spray (Fog)

Corrosion Tests .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 474Pretest Specimen Preparation for Salt Spray

Corrosion Tests .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 474Salt Spray Test Chamber Apparatus .. . . . . . . . . . . . . . . . . . . . . . . . . 475

Microbiologically Influenced Corrosion Testing .. . . . . . . . . . . . . . . . . . . . . . . . 478Biofilm Formation .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 478Mechanisms ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 479Electrochemical Techniques .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 480

Simulated Service Corrosion TestingSimulated Service Testing in the Atmosphere .. . . . . . . . . . . . . . . . . . . . . . . . . . . 487

Atmospheric Corrosion .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 487Types of Atmospheres .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 487Relative Corrosivity .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 488Environmental Factors .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 488Conducting Atmospheric Corrosion Tests .. . . . . . . . . . . . . . . . . . . 488Analyzing Atmospheric-Corrosion Tests .. . . . . . . . . . . . . . . . . . . . 491

xv



Simulated Service Testing in Water .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 495Test Method Selection and Precautions .. . . . . . . . . . . . . . . . . . . . . . 496Test Specimens .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 496Effect of Water Variables .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 496

Simulated Service Testing in Soil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 497Soil Characteristics .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 497Test Approach ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 498Specimen Preparation .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 498Specimen Burial . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 498Corrosion Measurements .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 499Specimen Retrieval . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 500Conclusions .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 500

In-Service Techniques for Damage Detection and MonitoringIn-Service Techniques—Damage Detection and Monitoring .. . . . . . . . . . 501

Electrochemical Methods .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 501Electromagnetic and Sonic Methods .. . . . . . . . . . . . . . . . . . . . . . . . . 503Optical and Fiber-Optic Sensing .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 504Fluorescence Methods .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 504Other Corrosion-Detection Methods .. . . . . . . . . . . . . . . . . . . . . . . . . 505Data Management and Expert System ... . . . . . . . . . . . . . . . . . . . . . 506Simulation and Modeling .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 506

Electrochemical Techniques for In-Service Corrosion Monitoring .. . . 509Direct Current Electrochemical Techniques .. . . . . . . . . . . . . . . . . 509Electrochemical Impedance Spectroscopy ... . . . . . . . . . . . . . . . . . 510

Corrosion Monitoring Techniques .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 514On-Line Corrosion Monitoring Techniques .. . . . . . . . . . . . . . . . . 514Direct Techniques .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 514Indirect Techniques .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 515System Considerations .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 516Examples of On-Line Corrosion Monitoring .. . . . . . . . . . . . . . . 517

Monitoring of Localized Corrosion .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 519Initiation of Localized Corrosion .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 519Electrochemical Noise Method ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 519Galvanically Coupled Differential Flow Cell . . . . . . . . . . . . . . . . 519Galvanically Coupled Crevice Cell . . . . . . . . . . . . . . . . . . . . . . . . . . . . 520Coupled Multielectrode Sensors .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 521Electrochemical Biofilm Activity Sensor .. . . . . . . . . . . . . . . . . . . . 522Nonelectrochemical Methods .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 523Conclusions .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 523

Infrared Imaging for Corrosion, Disbondments, and Cracks .. . . . . . . . . . 525Infrared Thermography Equipment .. . . . . . . . . . . . . . . . . . . . . . . . . . . 525Thermographic Process .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 526Imaging Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 527Sonic Thermography for Crack Detection .. . . . . . . . . . . . . . . . . . . 527

Corrosion Monitoring Using Microwave and Guided WaveNondestructive Evaluation .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 529

Microwave NDE Devices .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 529Guided Wave Ultrasonic Devices .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 530

Corrosion Monitoring for Industrial Processes .. . . . . . . . . . . . . . . . . . . . . . . . . . 533Selecting a Corrosion-Monitoring Method ... . . . . . . . . . . . . . . . . 533Direct Testing of Coupons .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 533Electrical-Resistance Probes .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 536Ultrasonic Thickness Measurements .. . . . . . . . . . . . . . . . . . . . . . . . . 536Polarization-Resistance Measurement .. . . . . . . . . . . . . . . . . . . . . . . . 537Measurement of Corrosion Potentials . . . . . . . . . . . . . . . . . . . . . . . . . 537Alternating Current Impedance Measurements .. . . . . . . . . . . . . 537Electrochemical Noise .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 538Hydrogen Probe .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 538Analysis of Process Streams ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 538Sentry Holes .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 539Side-Stream (Bypass) Loops .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 539

Strategies in Corrosion Monitoring .. . . . . . . . . . . . . . . . . . . . . . . . . . 539Interpretation and Reporting .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 540

Evaluating Forms of CorrosionEvaluating Uniform Corrosion .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 542

Mass-Loss Tests .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 542Other Test and Evaluation Methods .. . . . . . . . . . . . . . . . . . . . . . . . . . 544

Evaluating Pitting Corrosion .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 545Test Methods .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 545Examination of Pits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 546Evaluation of Pitting .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 546

Evaluating Crevice Corrosion .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 549Aspects of Crevice Corrosion Testing .. . . . . . . . . . . . . . . . . . . . . . . 549Guidelines for Crevice Corrosion Testing .. . . . . . . . . . . . . . . . . . . 549General Considerations .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 549Specific Crevice Corrosion Tests .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 550Multiple-Crevice Assembly Testing .. . . . . . . . . . . . . . . . . . . . . . . . . . 551Continuous Crevice Formers .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 552Evaluating Cylindrical Materials and Products .. . . . . . . . . . . . . 554Component Testing .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 556Electrochemical Tests .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 557Mathematical Modeling .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 559

Evaluating Galvanic Corrosion .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 562Component Testing .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 562Modeling .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 562Laboratory Testing .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 563

Evaluating Intergranular Corrosion .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 568The Purpose of Testing .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 568Tests for Stainless Steels and Nickel-Base Alloys .. . . . . . . . . 568Tests for Aluminum Alloys .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 569Tests for Other Alloys .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 570

Evaluating Exfoliation Corrosion .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 572Spray Tests .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 572Immersion Tests .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 573Visual Assessment of Exfoliation .. . . . . . . . . . . . . . . . . . . . . . . . . . . . 574

Evaluating Stress-Corrosion Cracking .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 575General State-of-the-Art . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 575Static Loading of Smooth Specimens .. . . . . . . . . . . . . . . . . . . . . . . . 576Static Loading of Precracked (Fracture Mechanics)

Specimens .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 583Dynamic Loading: Slow-Strain-Rate Testing .. . . . . . . . . . . . . . . 591Selection of Test Environments .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 592Testing of Aluminum Alloys .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 596Testing of Copper Alloys (Smooth Specimens) .. . . . . . . . . . . . 599Testing of Carbon and Low-Alloy Steels .. . . . . . . . . . . . . . . . . . . . 601Testing of High-Strength Steels .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 602Testing of Non-Heat-Treatable Stainless Steels .. . . . . . . . . . . . 603Testing of Magnesium Alloys .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 605Testing of Nickel Alloys .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 605Testing of Titanium Alloys .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 605Special Considerations for Testing of Weldments .. . . . . . . . . . 607Surface Preparation of Smooth Specimens .. . . . . . . . . . . . . . . . . . 607Interpretation of Test Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 608Selection of Test Method ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 611

Evaluating Hydrogen Embrittlement .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 617Toward a Definition .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 617Sources of Hydrogen ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 618Source of Stress .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 618Testing .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 618Interpretation of Test Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 622Prevention and Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 623

xvi



Evaluating Corrosion Fatigue .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 625Relationship between Corrosion-Fatigue Cracking,

Stress-Corrosion Cracking, and HydrogenEmbrittlement Cracking .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 625

Prediction of Corrosion-Fatigue Life .. . . . . . . . . . . . . . . . . . . . . . . . . 625Types of Corrosion-Fatigue Tests .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 625Standards and Recommended Practices for Fatigue

Testing .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 625Cycles-to-Failure Tests .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 626Environmental Effects and Fatigue .. . . . . . . . . . . . . . . . . . . . . . . . . . . 630Crack Propagation Tests .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 631

Evaluating Erosion Corrosion, Cavitation, and Impingement .. . . . . . . . . 639Standard Test Methods .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 639Other Tests .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 642Effects of Test Parameters .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 642Data Correlations .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 643

Evaluating Microbiologically Influenced Corrosion .. . . . . . . . . . . . . . . . . . . . 644Attack by Sulfate-Reducing Bacteria .. . . . . . . . . . . . . . . . . . . . . . . . 644Attack by Organisms Other Than SRB ... . . . . . . . . . . . . . . . . . . . . 645Testing for Microbiological Activity .. . . . . . . . . . . . . . . . . . . . . . . . . 647Risk Assessment Based on Operating Conditions .. . . . . . . . . 648

High-Temperature Gaseous Corrosion Testing .. . . . . . . . . . . . . . . . . . . . . . . . . . 650Factors Affecting High-Temperature Corrosion

and Materials Properties .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 650Measurement of High-Temperature Degradation .. . . . . . . . . . . 657High-Temperature Corrosion and Degradation

Processes .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 659High-Temperature Materials .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 663Testing Methods Used for Materials at High

Temperatures .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 665

Methods of Corrosion Protection ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 683

Introduction to Methods of Corrosion Protection .. . . . . . . . . . . . . . . . . . . . . . . 685Factors Affecting Corrosion Behavior .. . . . . . . . . . . . . . . . . . . . . . . 685Galvanic Couples .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 685Coatings .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 685Inhibitors .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 686

Corrosion Resistance of Bulk MaterialsIntroduction to Corrosion Resistance of Bulk Materials .. . . . . . . . . . . . . . . 687

Alloying .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 687Metallurgical Factors .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 687Mechanical Treatments .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 688

Corrosion Resistance of Aluminum Alloys .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 689Alloying to Improve Corrosion Resistance .. . . . . . . . . . . . . . . . . 689Mechanical Treatments to Improve Corrosion

Resistance .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 690Surface Treatment to Improve Corrosion Resistance .. . . . . . 690Processing to Improve Corrosion Resistance .. . . . . . . . . . . . . . . 691Selection of Fabrication Operations .. . . . . . . . . . . . . . . . . . . . . . . . . . 691

Corrosion Resistance of Magnesium Alloys .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 692Metallurgical Factors .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 693Causes of Corrosion Failures in Magnesium Alloys .. . . . . . 695

Corrosion Resistance of Stainless Steels and Nickel Alloys .. . . . . . . . . . 697Stainless Steels .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 697Nickel-Base Alloys .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 700

Corrosion Resistance of Titanium Alloys .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 703Corrosion Resistance of Titanium and Titanium-Base

Alloys in Aqueous Environments .. . . . . . . . . . . . . . . . . . . . . . . . . 703Passivating Titanium Oxides .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 703Corrosion Vulnerability of Titanium and Titanium

Oxides .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 703

xvii

Effects of Alloying on Active Anodic Corrosion ofTitanium ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 706

Effects of Alloying Additions on Titanium Passivity .. . . . . 707Formation of Amorphous or Vitreous Oxide .. . . . . . . . . . . . . . . 707Reduction of the Potential Gradient across Surface Film .. 708Enhancement of Atomic Bond Strength .. . . . . . . . . . . . . . . . . . . . . 708Lowering of the pH of Zero Charge .. . . . . . . . . . . . . . . . . . . . . . . . . 709Repassivation Behavior of Titanium and Titanium-Base

Alloys .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 709

Surface Treatments and Conversion CoatingsPhosphate Conversion Coatings .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 712

Structure and Function of the Phosphate Film ... . . . . . . . . . . . 712Phosphating Steps .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 714Physical and Chemical Properties .. . . . . . . . . . . . . . . . . . . . . . . . . . . . 717Processing Equipment and Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . 718

Chromate and Chromate-Free Conversion Coatings .. . . . . . . . . . . . . . . . . . . . 720Historical Perspective .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 720Chromate Conversion Coating Formation .. . . . . . . . . . . . . . . . . . . 720Morphology, Structure, and Composition .. . . . . . . . . . . . . . . . . . . 722Coating Properties .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 723Chromate-Free Conversion Coatings .. . . . . . . . . . . . . . . . . . . . . . . . . 727Chromate-Free Processes .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 727

Aluminum Anodizing .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 736Structure of Anodic Oxide Films ... . . . . . . . . . . . . . . . . . . . . . . . . . . . 736Anodizing .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 738Testing of Film Properties .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 740

Surface Modification Using Energy Beams ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . 741Ion Implantation .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 741Laser Surface Processing .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 744

Ceramic, Glass, and Oxide CoatingsPorcelain Enamels .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 750

Types of Porcelain Enamels .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 750Frits for Porcelain Enameling .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 750Properties of Porcelain Enamels .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 751Corrosion Resistance of Porcelain Enamels .. . . . . . . . . . . . . . . . 752Evaluation of Porcelain-Enameled Surfaces .. . . . . . . . . . . . . . . . 752

Chemical-Setting Ceramic Linings .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 755History of Chemical-Setting Silicates .. . . . . . . . . . . . . . . . . . . . . . . . 755Advantages and Disadvantages .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 755Current Technologies .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 756Corrosion Resistance .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 757

CVD and PVD Coatings .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 759Deposition Processes .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 759Coating Materials and Applications .. . . . . . . . . . . . . . . . . . . . . . . . . . 761

Pack Cementation Coatings .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 763Halide-Activated Pack Cementation .. . . . . . . . . . . . . . . . . . . . . . . . . 763Types of Pack Cementation Processes .. . . . . . . . . . . . . . . . . . . . . . . 763

Metal CoatingsElectroplated Coatings .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 772

Idealized Coating .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 772Substrates .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 773Design for Plating .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 775Advantages and Disadvantages of Electroplated

Coatings .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 777Effects of Deposition Parameters .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 778Mechanisms of Corrosion Prevention of Plated Coatings 778Applications for Electrodeposited Coatings .. . . . . . . . . . . . . . . . . 780Selection of Coatings .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 781Plating of Mill Products .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 782Electrochemical Predictions of Corrosion Performance .. . . 783Future Trends .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 784



xviii

Continuous Hot Dip Coatings .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 786Basic Principles .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 786Hot-Dip Coatings .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 788

Batch Process Hot Dip Galvanizing .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 794Surface Preparation .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 794Galvanizing .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 794Coating Weight and Thickness .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 795Factors Affecting Coating Thickness and Structure .. . . . . . . 795Mechanical Properties of the Coating and Steel

Substrate .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 796Fabrication Details for Galvanizing .. . . . . . . . . . . . . . . . . . . . . . . . . . 796Galvanized Coatings in Corrosion Service .. . . . . . . . . . . . . . . . . . 797Joining of Galvanized Structural Members .. . . . . . . . . . . . . . . . . 799Painting Galvanized Steel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 800Economics of Hot-Dip Galvanizing .. . . . . . . . . . . . . . . . . . . . . . . . . . 801Selected Applications of Hot Dip Galvanized Steel . . . . . . . . 801Galvanizing Specifications .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 801

Thermal Spray Coatings .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 803Thermal Spray Processes .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 803Controlling the Structure, Properties, and Performance

of Coatings .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 804Criteria for Coating Selection .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 804Costs of Thermal Spray Coatings .. . . . . . . . . . . . . . . . . . . . . . . . . . . . 807Case Studies .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 808Specification and Quality Control for Coatings .. . . . . . . . . . . . 809Summary ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 811Further Literature Sources for Thermal Spray .. . . . . . . . . . . . . . 811

Coatings and LiningsIntroduction to Coatings and Linings .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 814

The Effect of Legislation on the Coatings Industry .. . . . . . . . 814Coating Industry Response to Legislative Pressure .. . . . . . . . 814

Organic Coatings and Linings .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 817Autooxidative Cross-Linked Resins .. . . . . . . . . . . . . . . . . . . . . . . . . . 817Thermoplastic Resins .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 820Cross-Linked Thermosetting Coatings .. . . . . . . . . . . . . . . . . . . . . . . 825

Zinc-Rich Coatings .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 834Characteristics of Zinc-Rich Coatings .. . . . . . . . . . . . . . . . . . . . . . . 834Zinc-Rich Coatings with Organic Binders .. . . . . . . . . . . . . . . . . . 835Zinc-Rich Coatings with Inorganic Binders .. . . . . . . . . . . . . . . . . 835Comparisons of Inorganic and Organic Zinc-Rich

Coatings .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 836Paint Systems ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 837

Coating System Selection .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 837Surface Preparation .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 837Coating Application .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 840Quality Assurance .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 842

Rubber Coatings and Linings .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 845Rubber as a Protective Lining .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 845Commercial Lining Products .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 845Types of Rubbers .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 845Vulcanization .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 848Rubber Lining Application .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 848Inspecting Rubber Lining Work ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . 849Material and Installation Costs .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 850

Electrochemical and Corrosion Control MethodsAnodic Protection .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 851

History .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 851Anodic Protection Uses .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 851Comparison of Anodic and Cathodic Protection .. . . . . . . . . . . 851

Background and Theory .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 851Equipment Required for Anodic Protection .. . . . . . . . . . . . . . . . . 852Design Concerns .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 853Applications .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 853Economics .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 853

Cathodic Protection .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 855Fundamentals of Cathodic Protection .. . . . . . . . . . . . . . . . . . . . . . . . 855Types of Cathodic Protection .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 857Cathodic Protection Criteria .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 858Anode Materials .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 859Power Sources .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 861Design .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 861Case Histories .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 861

Corrosion InhibitorsVapor Phase Corrosion Inhibitors .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 871

Definition and Classification .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 871VCI Action Mechanism ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 871Structure of VCIs .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 872Vapor Pressure of VCIs .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 873VCI Evaluation Methods .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 873VCI Applications .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 874Protection of Aluminum ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 874Protection of Ferrous and Nonferrous Metals .. . . . . . . . . . . . . . 874

Corrosion Inhibitors for Oil and Gas Production .. . . . . . . . . . . . . . . . . . . . . . . 878Inhibitor Formulations .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 878Varying Characteristics of Oil and Gas Wells .. . . . . . . . . . . . . . 879Influence of Well Depth and Completion Method ... . . . . . . . 879Factors Influencing Corrosivity of Produced Fluids .. . . . . . . 880Methods of Inhibitor Application .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 880Corrosion Problems and Inhibition in Waterfloods .. . . . . . . . 882Bacteria-Induced Corrosion .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 883Laboratory Testing of Corrosion Inhibitors .. . . . . . . . . . . . . . . . . 883Monitoring Results of Inhibition in the Field .. . . . . . . . . . . . . . . 884Quality Control of Inhibitors .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 884Computerization of Inhibitor Treatment Programs ... . . . . . . . 884

Corrosion Inhibitors for Crude Oil Refineries .. . . . . . . . . . . . . . . . . . . . . . . . . . . 887Areas of Corrosion in the Refinery .. . . . . . . . . . . . . . . . . . . . . . . . . . . 887Types of Inhibitors .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 888Application of Inhibitors .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 889Corrosion Monitoring .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 889

Corrosion Inhibitors in the Water Treatment Industry .. . . . . . . . . . . . . . . . . . 891Boiler Systems ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 891Cooling Systems ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 893Corrosion Processes in Water-Recirculating Systems ... . . . 894Influence of Water Quality .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 895Corrosion Control in Municipal Water Systems ... . . . . . . . . . . 904

Designing for Corrosion Control and Prevention ... . . . . . . . . . . . . . . . . . . 907

Materials Selection for Corrosion Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 909The Materials Selection Process .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 909Selecting Materials to Prevent or Control Corrosion .. . . . . . 911Economics .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 925

Designing to Minimize Corrosion .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 929Design Considerations .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 929Corrosion Awareness .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 929Why Failures Occur .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 930Design and Materials Selection .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 930Design Factors That Influence Corrosion .. . . . . . . . . . . . . . . . . . . 932

Corrosion Economic Calculations .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 940Money and Time ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 940Notation and Terminology ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 940



xix

Methods of Economic Analysis .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 941Annual versus Continuous Compounding ... . . . . . . . . . . . . . . . . . 941Depreciation .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 942Generalized Equations .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 943Examples and Applications .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 944

Predictive Modeling of Structure Service Life .. . . . . . . . . . . . . . . . . . . . . . . . . . 946Design Philosophies .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 946Conceptual Framework ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 947Corrosion Fatigue Model Applications .. . . . . . . . . . . . . . . . . . . . . . 949Application of Models during Their Development .. . . . . . . . 954Conclusions .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 957

Direct Costs of Corrosion in the United States .. . . . . . . . . . . . . . . . . . . . . . . . . . 959Methodology ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 959Definitions .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 960Costs of Corrosion Control Methods and Services .. . . . . . . . 960Costs of Corrosion Estimated by Industry Sector

Analysis .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 962Conclusions Based on 1998 U.S. Study ... . . . . . . . . . . . . . . . . . . . 967Corrosion Prevention Strategies .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 967

Tools for the Corrosionist . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 969

Introduction to Tools for the Corrosionist . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 971Statistics .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 971Materials .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 971Instruments .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 971Additional Help .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 971Terminology and Presentation of Data .. . . . . . . . . . . . . . . . . . . . . . . 971

Statistics for the Corrosionist . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 972Definitions and Expressions .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 972Measurement .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 973Statistical Hypothesis Testing .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 973Simple Statistical Tests .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 975

Confidence Limits .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 975Sampling Issues .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 976Analysis of Variance .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 976Correlation and Regression .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 977

Materials Science for the Corrosionist . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 980Classification of Materials .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 980Properties .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 982Processing .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 987

Applications of Modern Analytical Instruments in Corrosion .. . . . . . . . 992Strategy for Selecting Analytical Approaches .. . . . . . . . . . . . . . 992Surface Structure Analysis .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 992Determination of Chemical Composition .. . . . . . . . . . . . . . . . . . . 992Analytical Methods .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 993

Information Sources and Databases for the Corrosionist . . . . . . . . . . . . . . . 999Societies and Associations .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 999Corrosion Standards, Specifications, Recommended

Practices, and Related Topics .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 999Sources of Corrosion Information .. . . . . . . . . . . . . . . . . . . . . . . . . . .1000Corrosion Databases and Data Compilations .. . . . . . . . . . . . . .1000Other Web Resources .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1000

Conventions and Definitions in Corrosion and Oxidation .. . . . . . . . . . . .1002Corrosion and Electrochemical Cells . . . . . . . . . . . . . . . . . . . . . . . .1002Cathodic Protection .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1004Electricity .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1006Oxidation .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1007

Reference Information ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1009

Glossary of Terms ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1011Corrosion Rate Conversion .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1028Metric Conversion Guide .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1029Abbreviations and Symbols .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1032Index ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1034



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Publication title Product code ASM Handbook, Volume 13A Corrosion: Fundamentals, Testing, and Protection

#06494G

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