Development of a Nonchromate Structural Adhesive Bond … · Cr2O3 Cr(+2a) CrCl2(+a) CrO4(-2a)...
Transcript of Development of a Nonchromate Structural Adhesive Bond … · Cr2O3 Cr(+2a) CrCl2(+a) CrO4(-2a)...
Development of a Nonchromate
Structural Adhesive Bond
Primer
Mark Jaworowski
UTRC
2014 AsetsDefense meeting
Report Documentation Page Form ApprovedOMB No. 0704-0188
Public reporting burden for the collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering andmaintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information,including suggestions for reducing this burden, to Washington Headquarters Services, Directorate for Information Operations and Reports, 1215 Jefferson Davis Highway, Suite 1204, ArlingtonVA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to a penalty for failing to comply with a collection of information if itdoes not display a currently valid OMB control number.
1. REPORT DATE NOV 2014 2. REPORT TYPE
3. DATES COVERED 00-00-2014 to 00-00-2014
4. TITLE AND SUBTITLE Development of a Nonchromate Structural Adhesive Bond Primer
5a. CONTRACT NUMBER
5b. GRANT NUMBER
5c. PROGRAM ELEMENT NUMBER
6. AUTHOR(S) 5d. PROJECT NUMBER
5e. TASK NUMBER
5f. WORK UNIT NUMBER
7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) United Technologies Research Center (UTRC),411 Silver Lane,East Hartford,CT,06108
8. PERFORMING ORGANIZATIONREPORT NUMBER
9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES) 10. SPONSOR/MONITOR’S ACRONYM(S)
11. SPONSOR/MONITOR’S REPORT NUMBER(S)
12. DISTRIBUTION/AVAILABILITY STATEMENT Approved for public release; distribution unlimited
13. SUPPLEMENTARY NOTES ASETSDefense 2014: Sustainable Surface Engineering for Aerospace and Defense, 18-20 Nov 2014, FortMyer, VA.
14. ABSTRACT
15. SUBJECT TERMS
16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT Same as
Report (SAR)
18. NUMBEROF PAGES
9
19a. NAME OFRESPONSIBLE PERSON
a. REPORT unclassified
b. ABSTRACT unclassified
c. THIS PAGE unclassified
Standard Form 298 (Rev. 8-98) Prescribed by ANSI Std Z39-18
2
Overview: Chromated Structural Adhesive Bond Primers
• Nominally 5 microns thick
• Prevent corrosion of base metal
• Applied to porous anodized surface
• Overcoated with non-inhibited epoxy adhesive
• High adhesive bond strength required for life of product
• Used in load bearing applications in flight-critical
hardware
• Anodized surface / primer interface stability is critical
• Typically 5% or less SrCrO4 by weight as sprayed
Fan Case Internal Bonding
Helicopter main rotor,
blade pockets, swashplate
Adhesive bond primer / anodize interface
All-composite propellers
Engine nacelles
Aerostructures
3
Previous testing of chromate free adhesive bond primers
Chromate inhibited Non chromate inhibited
168 hours ASTM B117 •Three companies (3M,
Cytec, Henkel) produce
aerospace structural
adhesive bond primers
•Long-running surveillance
of chromate-free alternatives
by UTC companies shows
weak corrosion inhibition
• (A) strontium
chromate- inhibited
bond primer, 2024 Al,
336 hours
• (B) Cytec BR6700-1,
2024 Al, 168 hours
• Inhibition technology
appears “low tech”: alkali
silicate, zinc phosphate
SEM: Cytec BR6700-1 (As-rec’d)
EDX: Cytec BR6700-1 (As-rec’d)
C
O
Al
Zn Al
CaSi
ClP
Element At% Atomic
ratio
Possbile
component
AlK 3.92 43.56
SiK 1.09 12.11
PK 0.09 1.00
ClK 0.17 1.89
CaK 0.79 8.78
ZnK 0.19 2.11
Cytec BR 6700-1 (As-rec'd)
Ca2SiO4,
CaAlSiO3,
ZnO
SEM: Cytec BR6700-1 (As-rec’d)SEM: Cytec BR6700-1 (As-rec’d)
EDX: Cytec BR6700-1 (As-rec’d)
C
O
Al
Zn Al
CaSi
ClP
EDX: Cytec BR6700-1 (As-rec’d)EDX: Cytec BR6700-1 (As-rec’d)
C
O
Al
Zn Al
CaSi
ClP
Element At% Atomic
ratio
Possbile
component
AlK 3.92 43.56
SiK 1.09 12.11
PK 0.09 1.00
ClK 0.17 1.89
CaK 0.79 8.78
ZnK 0.19 2.11
Cytec BR 6700-1 (As-rec'd)
Ca2SiO4,
CaAlSiO3,
ZnO
SEM: Cytec BR 6700-1 (post-test
scribe region) EDX: Cytec BR 6700-1
(post-test scribe region)Al
ZnZn CaPSi
Element At% Atomic ratio Comment
AlK 33.14 552.33
SiK 0.2 3.33
PK 0.17 2.83
CaK 0.09 1.50
MnK 0.06 1.00
CuK 0.24 4.00
ZnK 0.21 3.50
Zn, P,
Ca, and
Si
migrated
Cytec BR 6700-1 (post-test
scribe region)
SEM: Cytec BR 6700-1 (post-test
scribe region)
SEM: Cytec BR 6700-1 (post-test
scribe region) EDX: Cytec BR 6700-1
(post-test scribe region)Al
ZnZn CaPSi
EDX: Cytec BR 6700-1
(post-test scribe region)Al
ZnZn CaPSi
Element At% Atomic ratio Comment
AlK 33.14 552.33
SiK 0.2 3.33
PK 0.17 2.83
CaK 0.09 1.50
MnK 0.06 1.00
CuK 0.24 4.00
ZnK 0.21 3.50
Zn, P,
Ca, and
Si
migrated
Cytec BR 6700-1 (post-test
scribe region)
Development timeline for UTC Chromate-Free Adhesive Bond Primer
4
1999 -2000: UTRC / P&W Development of Concept
2001-2002 – UTRC / P&W
Joint Program Solubility
Regulation
2006 UTRC Capability
Project 7000-series Al
Performance Improvement
2009-2014 UTRC /
P&W/ 3M Product
Development and
Qualification
14121086420
2.0
1.5
1.0
0.5
0.0
-0.5
-1.0
-1.5
-2.0
Mo - Cl - H2O - System at 25.00 C
pH
Eh (Volts)
Mo
MoCl2OMoO2
MoO4(-2a)
14121086420
2.0
1.5
1.0
0.5
0.0
-0.5
-1.0
-1.5
-2.0
Ce - Cl - H2O - System at 25.00 C
pH
Eh (Volts)
CeClO
CeH2
CeO1.81
CeO2
Ce(+3a)
14121086420
2.0
1.5
1.0
0.5
0.0
-0.5
-1.0
-1.5
-2.0
Mn - Cl - H2O - System at 25.00 C
pH
Eh (Volts)
Mn
MnO2
Mn2O3Mn3O4
Mn(OH)2Mn(+2a)
MnO4(-a)
14121086420
2.0
1.5
1.0
0.5
0.0
-0.5
-1.0
-1.5
-2.0
Cr - Cl - H2O - System at 25.00 C
pH
Eh (Volts)
Cr
CrO2
Cr2O3
Cr(+2a)
CrCl2(+a)
CrO4(-2a)
Cr2O7(-2a)
Cr(OH)4(-a)
Nothing as good as Cr 6+…
14121086420
2.0
1.5
1.0
0.5
0.0
-0.5
-1.0
-1.5
-2.0
Ce - Mo - W - H2O - System at 25.00 C
C:\HSC5\EpH\CeMoW25.iep pH
Eh (Volts)
CeH2
Ce2(WO4)3
CeO2
Ce(+3a)
CeO(+a)
ELEMENTS Molality Pressure
Ce 1.000E+00 1.000E+00
Mo 1.000E+00 1.000E+00
W 1.000E+00 1.000E+00
Except multiple inhibitors?
Cerous citrate complex
regulates solubility of
multiple inhibitors
7705 Al / EcoTuff™
After corrosion test
Bright deposits:
50 wt% W + Zn
mixed oxide
3M Commercial
EW5000AS(P)3M Lab Batch
EW5000AS(L)
UTC EcoTuff®
Inhibitor
EW5000ET 3M Alt 1 3M Alt 2
EC3917
chromated
control
AS
TM
B117 e
xposu
re tim
e, hours
2000
1
500 1000 5
00
Optimized for multiple alloys Extensive corrosion and
mechanical property testing
Specification for engine use (EW-5000ET), testing of
developmental sol gel compatible primer (EW-5005)
5
Corrosion Science Model used to Develop Non Chromate Inhibitor
Corrosion involves at least two electrochemical reactions:Anodic (metal oxidation) and cathodic
(i. e., oxygen reduction)
!cathodic sites ~ 0 2+ 2H20 + 4e-~ 40H- _j
nodic sites: AI -7 AI3++Je-
' I
I
, " , ' ' ' ' \ I
AI-Cu-Fe-Mn
.... ~-- ..............
AI 2024-T3 (AI- 4%Cu-1 . 5%Mg)
' ' ' \ I
Anodic~ Cathodic?
/ A/20 3 passive film
An efTective coJTO ion inhibitor J ten1 11111 t den1on trate both anodic and cathodic inhibition in order to efTectivel; prevent corro ion o_f A! a1loJ
C Unltld Technolagles Research Center
Thermochemical Strategy for Multimode Inhibitor
6
109876543
1.0
0.8
0.6
0.4
0.2
0.0
Initial pH
Co
nce
ntr
ati
on
, m
mo
l/lit
er
Zn 0.0 0
Zn 0.0 1
Zn 0.2 0
Zn 0.2 1
Species PO2 mol/liter
[NaCl],
Zn 2+
109876543
0.5
0.4
0.3
0.2
0.1
0.0
Initial pH
Co
nce
ntr
ati
on
, m
mo
l/lit
er
Mo 0.0 0
Mo 0.0 1
Mo 0.2 0
Mo 0.2 1
Species PO2 mol/liter
[NaCl],
MoO4 2-
109876543
0.30
0.25
0.20
0.15
0.10
0.05
0.00
Initial pH
Co
nce
ntr
ati
on
, m
mo
l/lit
er
Ce 0.0 0
Ce 0.0 1
Ce 0.2 0
Ce 0.2 1
Species PO2 mol/liter
[NaCl],
Ce 3+
Solubility test set-up
Syringe for in-
situ sampling
manifold
Test
flaskWater bath for
temperature
control
Thermocouple
Thermochemical identification
of inhibition systemCerous citrate chelation
complex regulates solubility
14121086420
1.8
1.3
0.8
0.3
-0.2
-0.7
-1.2
-1.7
-2.2
Ce - Al - Mo - W - H2O - System at 25.00 C
C:\HSC4\AlCeMoW2.iep pH
E(Ag/AgCl) (Volts)
CeH2
Ce2(WO4)3
CeO2
Ce(+3a)
CeO(+a)
ELEMENTS Molality Pressure
Al 1.000E+00 1.000E+00
Ce 1.000E-02 1.000E+00
Mo 1.000E-02 1.000E+00
W 1.000E-02 1.000E+00
Ce2(MoO4)3
Target solubilities of separate corrosion inhibiter achieved
Electrokinetic Confirmation of Active Inhibition in Coatings
7
Schematic of defect production and samples for salt spray (a) and EIS test (b).
Al2023-T3
Conversion coating
Primer
Top view
(b)
WC tip0.1-0.2 mm
Top view
(a)
WC tip0.1-0.2 mm
Dynamic damage testing of trial primers Static DC Testing on Bare Al
10 -9
10 -8
10 -7
10 -6
10 -5
10 -4
10 -3
10 -2
-1.00
-0.75
-0.50
-0.25
I (Amps/cm 2 )
E (
Volts)
EcoTuff® Ce 3+ /MoO 4
2 - /WO 4 2 - (I)
CrO 4 2 -
NaCl
Pitting potential improved
0.1m M
10 m M
- 0.35
AA2024 - T3 exposed to Ar - deaerated solutions
10-9 10-8 10-7 10-6 10-5 10-4 10-3 10-2-1.8
-1.6
-1.4
-1.2
-1.0
-0.8
-0.6
I (Amps/cm2)
E (
Volts)
EcoTuff®
CrO42-
Ce3+
Ce3+/MoO42-/WO4
2-(I)
Al2024-T3 exposed O2 saturated solutions
Cathodic inhibition comparable to Cr 6+
3M / P&W / UTRC Corrosion Test Results PAA treated 2024-T3 Al
8
3M Commercial
EW5000AS(P) 3M Lab Batch
EW5000AS(L)
UTC EcoTuff®
Inhibitor
EW-5000ET 3M Alt 1 3M Alt 2
EC3917
chromated
control
AS
TM
B11
7 e
xp
osu
re tim
e, h
ou
rs
20
00
1
50
0 1
00
0 5
00
2014 R&D 100 Award to UTRC / P&W / 3M Team
9
Back row (L to R):
Mark Jaworowski, UTRC, Michael Kryzman, UTRC
Front row (L to R):
Xiaomei Yu, Sikorsky Aircraft Corporation, Weilong Zhang, UTRC
Promila Bhatia,, Pratt & Whitney
Other UTRC Team members:
Sara Arsenault
Tom Garosshen
Steve Gore
Foster Lamm
Vince Nardone
Xia Tang
Other P&W team Members:
Thomas Hanlon
Camelia Galos
Alex Korzh
Nathalie Laurent
Ray Martina
John Putnam
Charlie Watson
3M Team Members:
Lance Chen
Eric Forbes
Michael S. Newman (Primary Contact)
Dmitriy Salinkov
Pete Steinhagen