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1、上海交通大学硕士学位论文冷气动力喷涂铬锆铜涂层制备及组织性能研究姓名：张田宇申请学位级别：硕士专业：材料学指导教师：宋洪伟;张俊宝20081201摘要金材料不同的是，冷喷涂材料在退火过程中具有第三个能量转变锋，即870℃粒子界面的愈合。由于粒子界面的消失需要的激活能最大，能量释放也更为显著。退火后涂层各项性能可由以上涂层退火特征温度的晶体结构演变解释。随退火温度的升高，涂层孔隙率增大。500℃退火后，涂层开始出现塑性屈服，抗拉强度达到最大值140MPa。随退火温度的升高，尽管涂层塑性进一步得到改善，但涂层内部孔隙的增多导致
2、涂层抗拉强度下降。综合各项性能指标，500℃退火使涂层性能达到最优，此时涂层具有与基体材料较为相近的硬度，最高的抗拉强度和相对较高的延伸率和导热率。关键词：冷气动力喷涂，铬锆铜涂层，喷涂气体参数，退火处理，组织性能IIABSTRACTABSTRACTColdsprayisanemergingcoatingtechnology.Inthisprocess,acoatingisdepositedthroughplasticdeformationofmetallicsprayparticlesinacompletelysolid
3、stateviahighvelocityimpact.Comparewithtraditionalthermalspraytechnology,thismethodhastheadvantageofdepositionofchemicalactivelyelementcoatingsaswellasminimizingoreveneliminatingthedeleteriouseffectsinherenttotheconventionalthermalspray.Itcanbeusedinrepairingthecry
4、stallizerinordertoprolongitsservicelife,whichisparticularlyimportantbothinengineeringandacademicfield.Inordertoimprovethecoating,responsesurfacemethodologyexperimentalapproachwasemployedtooptimizethecarriergasparametersincoldsprayprocess.Withintheinvestigationofde
5、positionefficiency,density,micro-hardnessandfrictioncoefficient,thebestcoupleofgastemperatureandpressureisselectedbyMinitabanalyzingsoftware.WiththeaidofOM,SEM,EPMA,micro-hardnessandtensiletester,micro-frictiontester,laserthermalconductivityinstrument,microstructu
6、reandmechanicalpropertiesofas-sprayedCrZrCualloycoatingwerestudied.Thebondingmechanismofthecold-sprayedmetalliccoatingsandtheinfluenceofalloyingelementswerealsodiscussed.Theinfluenceofcoatingthicknesswasalsoinvestigated.Byusingdifferentialscanningcalorimetryanalyz
7、erandhigh-temperaturelaserscanningmicroscope(confocal),theinsituobservationofmicrostructureevolutionandthermalchangesinannealingprocesswascarriedout.Theeffectsofannealingheattreatmentwerealsodiscussed.Experimentalresultsshowedthatthecarriergastemperatureandpressur
8、ehavegreatinfluenceondepositionefficiency,densityandotherpropertiesofCrZrCualloycoating,affecttheperformancesignificantly.Althoughtheseparametersmainlyc
