Wear Mitigation by the Use of Surface Coatings
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Wear Mitigation by the Use of Surface Coatings by Stephen Huse
description
Wear Mitigation by the Use of Surface Coatings. by Stephen Huse. Outline. Abrasion and adhesion description Variables that change the wear rate Variables changed by coatings Surface coating processes Physical Vapor Deposition (PVD) Chemical Vapor Deposition (CVD) Electrodeposition - PowerPoint PPT Presentation
Transcript of Wear Mitigation by the Use of Surface Coatings
Wear Mitigation by the Use of Surface Coatings
by Stephen Huse
OutlineAbrasion and adhesion description
Variables that change the wear rateVariables changed by coatings
Surface coating processesPhysical Vapor Deposition (PVD)Chemical Vapor Deposition (CVD)ElectrodepositionThermal Spray
AbrasionPhysical interference of
surface asperitiesTypes:
CuttingCracking (brittle fracture)Ploughing
AdhesionCold weld of surface
asperitiesSimilar materials such as
steel on steel Wear removes oxide layer
Variables That Change the Wear RateFriction
Surface roughnessNormal Forces
Temperature Surface hardness Surface materials Environmental
considerationsHKN
LV
NF ksf ,
Variables Changed by CoatingsSurface Hardness
Reduces abrasive wearMay increase brittleness
FrictionReduces force for toolingReduce heat generated
Surface MaterialsReduces adhesive bondingExample: steel - steel
becomes steel - ceramic coating - steel
Physical Vapor Deposition ProcessVacuum environmentcoating powder is melted and
transported to substrateCathodic arcElectron beamPlasma torchMagnetic
Coating condenses on substrateNASA plasma spray PVDAdvantages
High HardnessLow friction
Disadvantage: requires line-of-sight
Chemical Vapor Deposition ProcessChemically controlled atmospheric
environment. Substrate heated to 2000°FAtmosphere chemically reacts at surfaceExamples:
Titanium cloride (gas), nitrogen, and hydrogen → titanium nitride coating
Titanium chloride (gas), methane, and hydrogen → titanium carbide coating
Superior adhesion of the coating to the substrate
Used for synthetic diamond growth
ElectrodepositionExample: Chrome platingResists corrosive wearIncreased hardnessReduced friction
Thermal SprayExample: Plasma spraySimilar to PVD, but no vacuumSubstrate is preheated to
remove impurities
Referenceshttp://
www.diamondtc.com/diatiger/about.htmlhttp://www.Gordonengland.co.ukhttp://www.signalplating.comhttp://www.sulzer.comhttp://www.surface.mat.ethz.chhttp://www.pall.comhttp://www.manmadediamondinfo.comhttp://www.ptli.comhttp://www.directindustry.com
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