资源描述：
《Porosity in plasma electrolytic oxide coatings》由会员上传分享，免费在线阅读，更多相关内容在学术论文-天天文库。
1、ActaMaterialia54(2006)1985–1993www.actamat-journals.comPorosityinplasmaelectrolyticoxidecoatingsJ.A.Curran,T.W.Clyne*DepartmentofMaterialsScienceandMetallurgy,CambridgeUniversity,PembrokeStreet,CambridgeCB23QZ,UKReceived9August2005;receivedinrevisedform27November2005;accepted16Decem
2、ber2005Availableonline28February2006AbstractPlasmaelectrolyticoxidecoatingsaregenerallyassumedtobealmostfullydense.However,evidenceispresentedhereforthepresenceofsub-micrometre,surface-connectedporosityinsuchcoatings,onaluminiumalloys,atlevelsoftheorderof20%.Thisevidencecomesfromden
3、sitometry,mercuryporosimetry,heliumpycnometry,BETadsorptionmeasurementsandhigh-resolutionscanningelectronmicroscopy.Theveryfinescaleoftheporosity(porediameter10to100nm),coupledwithseveredifficultiesinmakingunambiguousmicrostructuralobservations,mayaccountforthefailuretodetectthisfeatu
4、repreviously.Itispointedoutthatvariousmeasuredprop-erties,suchasYoung’smodulusandthermalconductivity,areconsistentwiththepresenceoftheserelativelyhighporositylevels.Var-iousotherobservedcharacteristicscanalsobeexplainedonthisbasis.Finally,apossiblemechanisticoriginfortheporosityispr
5、oposed.Ó2006PublishedbyElsevierLtdonbehalfofActaMaterialiaInc.Keywords:Coating;Crystallineoxides1.Introductionmechanismofcoatinggrowthremainssomewhatunclear,particularlyintermsofthelocalphysicalprocessesoccur-Plasmaelectrolyticoxide(PEO)coatings[1–4](some-ringduringgrowth.Thecoating
6、structurealsoremainstimesreferredtoasmicro-arcoxidecoatings,orspark/ratherpoorlycharacterised.dischargeanodiccoatings)areformedbysubstrateoxida-Thepresentpaperisfocusedontheporosityandporetioninanaqueouselectrolyteviaaseriesoflocalisedelectri-architectureexhibitedbyPEOcoatings.There
7、hasbeencaldischargeevents.Thesedischargesallowoxidegrowthverylittlepreviousworkaimedspecificallyatthisarea,toproceedsoastoproducefilmswiththicknessesofthealthoughithasgenerallybeenstatedandassumedthatorderof100lm.Theyarebeingexploredanddevelopedtheporositylevelislow.Figuresoftheordero
8、fafewforvariousappl
