真空预氧化对冷喷涂NiCoCrAlY涂层氧化行为的影响  

Effect of Vacuum Pre-oxidation on Oxidation Behavior of NiCoCrAlY Coating Prepared by Cold Spray

作　　者：张林伟 王鲁[1] 王全胜[1] 宁先进[1] 

机构地区：[1]北京理工大学材料学院,北京100081

出　　处：《材料工程》2014年第1期1-5,29,共6页Journal of Materials Engineering

基　　金：高等学校博士学科点专项科研基金(20101101120030)

摘　　要：利用冷喷涂技术制备了NiCoCrAlY涂层,并对涂层进行了真空预氧化处理。结合X射线衍射,扫描电镜和能谱分析等方法分析了NiCoCrAlY涂层真空预氧化前后的微观组织结构,并研究了真空预氧化处理对NiCoCrAlY涂层在1050℃下氧化行为的影响。结果表明:冷喷涂NiCoCrAlY涂层含氧量为0.25%(质量分数),孔隙率小于0.36%。真空预氧化处理使涂层由γ-Matrix Ni-Co-Cr单相结构转变为γ-Matrix Ni-Co-Cr固溶体和β-(Ni,Co)Al金属间化合物双相结构,并在涂层表面生成厚约0.47μm连续、致密的α-Al2O3氧化膜。喷涂态涂层和真空预氧化涂层在1050℃氧化200h后表面均生成致密、连续的以α-Al2O3为主的氧化膜。真空预氧化处理在100h内抑制了涂层表面尖晶石氧化物的形成,同时降低了氧化膜生长速率。A NiCoCrAlY coating was prepared by cold spray.After deposition,the pre-oxidation of the coating was performed by vacuum heat treatment.The microstructure and phase structure of the coating were characterized by XRD,SEM and EDS.The effect of vacuum heat treatment on the oxidation behavior of NiCoCrAlY coatings at 1050℃ was also studied.The results show that the as-sprayed coating presents a dense structure with low porosity （less than 0.36％） and low oxygen content （0.25％ mass fraction）.Vacuum heat treatment converts the single-phase （γ） as-sprayed coating to a two-phase γ/β microstructure,and a continuous,uniform and dense α-Al2 O3 layer is formed,with an average thickness of 0.47μm.After oxidation for 200h at 1050℃,a dense and continuous thermally grown oxide（TGO）,mainly composed of α-Al2O3,is formed on the surface of as-sprayed and vacuum heat-treated coating.Vacuum heat treatment can postpone the formation of spinel in a certain time （100h） and decrease the growth rate of TGO.

关 键 词：MCRALY涂层 冷喷涂 氧化行为 真空预氧化 

分 类 号：TG174.422[金属学及工艺—金属表面处理]