对金属保护的抗刮伤、耐磨损和缓蚀有机、无机混合材料保护层

Scratch,wearandcorrosionresistantorganicinorganichybridmaterialsformetalsprotectionandbarrier,对金属保护的抗刮伤、耐磨损和缓蚀有机、无机混合材料保护层,孙新肖,论文概况,摘要(Abstract)材料与实验(ExperimentalDetails)结果与讨论(Restultsanddiscussion)结论(Conclusions),2,Abstract,Polysiloxanesarewidelyusedasprotectivebarrierstodelayerosion/corrosionandincreasechemicalinertnessofmetalsubstrates.Inthepresentwork,ahighmolecularweightmethylphenylpolysiloxaneresinwasdesignedtomanufactureaprotectivecoatingforFe430Bstructuralsteel.Visualappearanceandmorphologyofthecoatingswerestudiedbyeldemissionscanningelectronmicroscopyandcontactgaugesurfaceprofilometry.Micro-mechanicalresponseofthecoatingswasanalyzedbyinstrumentedprogressiveloadscratch,whilewearresistancebydryslidinglinearreciprocatingtribologicaltests.,3,Abstract,Lastly,chemicalinertnessandcorrosionenduranceofthecoatingswereevaluatedbylinearsweepvoltammetryandchronoamperometryinaggressiveacidenvironment.Theresultingresinsyieldedprotectivematerials,whichfeatureremarkableadhesiontothesubstrate,goodscratchresistanceandhighwearendurance,thuslayingthefoundationstomanufacturelonglastingprotectivebarriersagainstcorrosionand,moreingeneral,againstaggressivechemicals.,4,ExperimentalDetails,Materials：ThesubstratesareflatslabsinstructuralFe430Bsteel40mmlong,30mmwideand5mmthick.Thehybridorganic-inorganicresinisamodiedmethylphenylvinyltriethoxysilane.AlMg(4.5wt.%)powdersmetalpigments.Additiveslikethickeners,flowpromoters,wettingagentsanddefoamers.,5,ExperimentalDetails,Manufacturingprocess:1.Metalsubstratespre-treatedbyalappingmachinewithsandpaper(Al2O3400meshsize)untiltheachievementofafairlysmoothandhomogenousmorphology.2.Pre-treatedsubstrateswerewashedinanultrasonicbathofisopropylalcohol,followedbyanadditionalwashinginasolutionofanalkalinedetergentindemineralizedwater.3.Thesubstrateswererinsedwithbi-distilledwateranddriedovernightat60Cinavacuumoven.4.Pre-treatedsubstratesweresprayed(2barfeedingpressure,nozzle0.8mm,stand-offdistance400mm)withdilutedpolysiloxaneresinswithorwithoutthemetalpigmentsdispersedinsideorwithapre-hydrolyzedsolutionofvinyltriethoxysilane(2wt.%)inethanol(96%)anddemineralizedwater.,6,ExperimentalDetails,Intheformercase,thecoatedsubstrateswerepre-driedforfewminutesatenvironmentalconditions(20Cand40%HR)andsubsequentlybakedinconvectionovenat250Cfor45mintocross-linkthepolysiloxaneresin.Inthelattercase,theorgano-silaneinterlayerswerepre-driedforfewminutesatenvironmentalconditions($20Cand40%HR)andsubsequentlybakedinconvectionovenatapproximately100110Cfor10mintoachievethefullconsolidationoftheprimer.Theorgano-silanecoatedmetalsubstrateswerethenrecoatedwithasecondlayerofthepolysiloxaneresin.Itsdringprocessisthesameastheformercase.,7,ExperimentalDetails,AllthemanufacturedcoatingsaresummarizedinTable1.FourreferencesamplesinFe430B,uncoatedorZncoated(depositedbyhotdipping,coldspraying,electro-galvanizing),withlayersofequivalentthicknesstotheabovementionedhybridorganicinorganiccoatings,wasusedforcomparativepurposes.,8,ExperimentalDetails,Experimentalprocedure:Coatingsthicknessandtheiruniformitywasmeasuredbyamagneticinductivegauge,performingninemeasurementsequallydistributedoverthecoatedsurface.Cross-cuttapetestmethodandpenciltestmethodwereperformedtoevaluatethecoatingsadhesiontothesubstrateandtheirhardness.CoatingsmorphologywasanalyzedbycontactinductivegaugeofaCLIproler.StoredproleswereelaboratedusingtheTalyMap3.1software,andmainroughnessparameterswereevaluated.AFieldEmissionGunScanningElectronMicroscopewasusedtoexaminethevisualappearanceandmorphologyofthecoatings.,9,ExperimentalDetails,Scratchtestswereperformedontheprotectivecoatings,operatingin“progressiveload”mode,usingaRoundedConicalRockwellCdiamondindenter,with200and800umtipradius.Wearenduranceofthecoatingswasassessedbyball-on-flatlinearreciprocatingtribologicaltests,usingsphericalcounterpartElectrochemicaltestswereperformedbydippingthesubstratesinanelectrolyticcellwithanaqueoussolutionofH2SO4(0.5M).Itmainlyconcludslinearsweepvoltammetryandchronoamperometrytoexaminecoatingsperformanceofcorrosionresistant.,10,Resultsanddiscussion,11,Resultsanddiscussion,图2，是金属基质和各涂层表面的粗糙度,涂层R和V/R的平均粗糙度大约在0.16和0.17um，这个数值比经摩擦后金属基质的粗糙度（大约0.45um)还要小。涂层P和V/P的平均粗糙度大约在0.37um。而涂层RP和V/RP的平均粗糙度大约在0.17-0.2之间，和涂层R和V/R的平均粗糙度很接近。,涂层R和V/R与涂层P、V/P、RP和V/RP在外貌和粗糙度的不同主要是因为后者添加了直径大约为10um的Mg-Al粉体的颜料。虽然这个研究中涂层的厚度限制在60-80um，但是一些颜料仍然可从涂层表面凸起，它们增加了表面的粗糙度。,12,Resultsanddiscussion,图3，金属基质和各涂层表面的3D形貌,(a).金属基质(b).涂层R(c).涂层P(d).涂层RP(e).V/REF(f).涂层V/R(g).涂层V/P（h).V/RP,13,Resultsanddiscussion,图4显示的是在干滑动直线往复摩擦磨损实验中过程中，相对滑距，涂层的磨损量的变化。,由图上可看出涂层R和V/R有最大的磨损量，这个变化关系接近于线性且没有任何初始运行的步骤，故磨损率是个常数。没有任何初始运行的步骤可能是因为涂层表面相当的光滑，因此针可以接触到树脂的表面，从摩擦磨损实验开始就进行均匀的摩擦。,涂层P和V/P变化关系中有两个分支，且他们的磨损量分别比涂层R和V/R要低5-10倍。,涂层RP和V/RP有一个中等的摩擦相应。从图上可看出在变化过程中斜率突然降低。,14,Resultsanddiscussion,Fig.5.SEMimagesoftheresidualscratchpatterns,usingan800umtipradiusindenterfor:(a)TypeR;(b)TypeV/R;(c)TypeP;(d)TypeV/P;(e)TypeRP;(f)TypeV/RP.,15,Resultsanddiscussion,Whentheexternalloadovercomestheultimatestrengthofthecoatingmaterial,fracturesaregenerated.,16,Resultsanddiscussion,Fig7.Trendsofthepenetrationandresidualdepthsforaprogressiveloadscratchtestusingan800umtipradiusindenter.,17,Resultsanddiscussion,Fig.7.Trendsofthepenetrationandresidualdepthsforaprogressiveloadscratchtestusingan800lmtipradiusindenter.,18,Resultsanddiscussion,Fig.8.SEMimagesoftheresidualscratchpatterns,usinga200umtipradiusindenterfor:(a)TypeR;(b)TypeV/R;(c)TypeP;(d)TypeV/P;(e)TypeRP;(f)TypeV/RP.,19,Resultsanddiscussion,Fig.9.Trendsofthepenetrationandresidualdepthsforaprogressiveloadscratchtestusinga200lmtipradiusindenter.,20,Resultsanddiscussion,Fig.9.Trendsofthepenetrationandresidualdepthsforaprogressiveloadscratchtestusinga200lmtipradiusindenter.,21,Resultsanddiscussion,Fig.10.Chronoamperometryperformedontheprotectivecoatings.,Fig.10reportstheanodicpolarizationcurvesfortheprotectivecoatingsystemsandtheywerecomparativelyevaluatedwiththecorrespondingcurvesofthebareZncoated(byhotdipping,electro-galvanizing,coldspraying)Fe430Bsubstrates,22,Resultsanddiscussion,Table1.summarizesthecorrosionpotentialsandcurrentsevaluatedaccordingtoTafelsmethod.,23,Resultsanddiscussion,Fig.11.Imagesofthecoatingsafterlinearsweepvoltammetry.,Fig.11summarizestheresultsofthechronoamperometry,24,Resultsanddiscussion,Fig.12.Linearsweepvoltammetryperformedontheprotectivecoatings.,25,Conclusion,Erosion/corrosionenduranceandmechanicalstrengthofthecoatingswerefoundtobestrictlycorrelated.Thecoatingsshoweddifferentresponsesaccordingtotheirarchitecture.Basedontheexperimentalndings,thefollowingconclusionscanbedrawn:themethylphenylpolysiloxaneresincanformsolid,thickandwelladheredcoatingsonthemetalsubstrate;adhesioncanbealsopromotedbycoarseningofthemetalsurface;thevinyltriethoxysilaneintermediatelayercanadditionallyimprovethecoatingadhesiontotheunderlyingmetalsubstrateasitfeatureshighlyreactivealkoxygroupscoupledwithalim-itedsterichindrance,whichfavorstheirreactivity;,26,Conclusion,thecoatings,whichi