激光熔覆抗氧化涂层及其性能的研究

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1、摘要本文采用激光熔覆的方法谯T1A1金属间化合物基体ii沉积耐商潞涂层，分别选取NiCoClAIY、NiCoCrA]Y+5％Al，毡阻及NiCoCrAIY+20％AI进行熔覆。并鼠甩金相、曼微硬度、X～射线衍射(XRD)、摆捕电镜(SEM)和能谴(EDX)等分析手段，分副研究了滁层的组织结构及高溢氧化行为。工艺实验结果袭明，用一定爨的硝酸纤维素和MCrAIY台金粉术潺合后，用丽酮调成糊状。涂覆于基材表面的方法，在后续的激光熔覆中能形成高旗量的McrAIY抗氧化涂层。激光熔覆工艺参数为900W的输出动率和350ra

2、m／rain的扫描述度是实验优选的嚣健工芜参数。氧化蜜验结果蓑明，在1000℃条件下氧化100小时意，NiCoCrAiY葺[1NiCoCrAIY+5％hl。0。滁层表面形成了Ti0。、A1：0，等的复合氧化膜，主要是Tio^。而NiCoCrhlY+20％Al涂层表面的氧纯腾剐主要是A1。0，膜。氧化动力学曲线表喇，抗氧化性从优到劣的次序是HiCoCrhIY+20％AI、NiCoCrAIY}_5％A1—0NiCoCrAIY。分析囊明，Al的添匀珏一方顽使得晶粒细化，舅～方面阻碍其它离子扩数。同时增加了涂屡中对抗氧化

3、起作用的Al离子储备。有利于形成比较致密的Aj，砚骥，增强涂屎抗氧化性。美键诵TiA!垒篇蛹化台物：硝酸纤维素；激光烙覆；NiCoCrMY涂层高温氧化!!塞i!些奎篓三茎竺：圭耋篁些兰AbstractALasercladdingdcpositiontcchniqucwasperformedtomake(NiCoCrAIY)coatingThiscoatisexpectedtoworkasaHigh—temperatureresistforTiAlintermetallicsubstrate．Metallograp

4、hicanalysis，microhardness，SEM，XRDwereusedtofindtheappropriateLasercladdingparameters(powerandscanvelocity)，thedepositmorphologyandtheoxidationbehaviorofthecoatStudyshowedthatamixtureofPyroxylinandalloypowderandacetone-whichwasdepositedonthesubstrate，canhelpto

5、formahi出performancecoating．AboutLasercladdingparameters，900Winpowerand350mm／mininvelocityarerelativelygoodAfter100hoursoxidationexperimentat1000。CamixedTi02、A1203layerwasformedatthetopof(NiCoCrAIY)coatingand(NiCoCrAIY+5％AIaOs)coating．Howeverthelayerontopof(Ni

6、CoCrAIY+20％AI)coatingwasmainlyA1203Theresultsofhi曲temperatureoxidationtestsinairat1000"Cshowedthattheoxidationresistanceofthelasercladding(NiCoCrAIY+20％AI)wassignificantlyhigherthanthatof(NiCoCrAlY+5％A1203)and(NiCoCrAlY)coatings．AnalysistellsthattoaddAluminum

7、inthepowdercanhelptoformahighqualitycoatingThemechanismsofAItoimproveoxidationresistancewereDiscussed．AicanfinethegrainsizeofcladdingcoatingsandhinderthediffusionofotherionsItcarlalsoincreasethecontentofA13+inthecoatingWhichallensBretoformahiglldensityA1203la

8、yeronthesubstrateandtoproranteitsoxidationresistanceKeywords7fiAlintcrmctallicsubstrate；lasercladding；NiCoCrAIYcoating；Pyroxylin；high--temperatureoxidation．111．独创性声明本人声明所呈交的论文是我个人在导师指导下进行