放电等离子烧结CoCrW合金的高温摩擦学行为  

High-temperature Tribological Behavior of Spark Plasma Sintered CoCrW Alloy

作　　者：唐晨 于成涛 王群昌 陈明辉 王福会 TANG Chen;YU Chengtao;WANG Qunchang;CHEN Minghui;WANG Fuhui(School of Materials Science and Engineering,Northeastern University,Shenyang 110819,China)

机构地区：[1]东北大学材料科学与工程学院,沈阳110819

出　　处：《表面技术》2025年第3期80-89,共10页Surface Technology

基　　金：国家自然科学基金(51871051);第四批宁夏青年科技人才托举工程项目(TJGC2019028);兴辽英才计划(XLYC2203133);教育部中央高校基本业务费(N2302018);宁波余姚市科技创新项目(2023J03010010)。

摘　　要：目的阐明CoCrW合金在400~800℃下的高温摩擦学行为和釉质层的生成及演变机制。方法通过放电等离子烧结(SPS)工艺制备CoCrW合金,利用往复式摩擦磨损试验机和白光干涉仪测试并表征合金在400~800℃下的高温摩擦学性能。采用SEM、EDS、EBSD、EPMA及拉曼光谱等手段表征合金与磨损表面的显微组织、物相组成及元素成分。结果采用SPS烧结的CoCrW合金的成分、组织均匀,弥散分布的Cr7C3起到了抑制晶粒长大的作用。在温度为400℃时,由于无足够的氧化物磨屑在其表面压实及摩擦烧结进而生成釉质层,因此合金表面发生了严重的磨粒磨损,磨损率为2.55×10-4 mm^(3)/(N·m)。在600℃下,合金磨损表面局部生成了具有保护性的岛状氧化膜,减弱了硬磨粒的犁削作用,磨损率为4.03×10^(-5) mm^(3)/(N·m)。在800℃下,合金磨损表面生成了由Cr_(2)O_(3)、CoCr_(2)O_(4)及Co_(3)O_(4)组成的稳定釉质层,磨损率较400℃下降低了91%,为2.36×10^(-5)mm^(3)/(N·m)。结论温度的提升,加速了离子的扩散及磨屑的细化,促进了氧化物颗粒在磨损表面的烧结。在800℃下的磨损初期,保护性釉质层的生成阻碍了亚表面的塑性变形,避免了在600℃下的磨损初期时变形区的整体断裂。金属离子与氧离子的快速扩散促成了内部富Cr氧化层及表面混合氧化层的形成,在800℃下使得合金表面生成了稳定的釉质层。CoCrW alloy(Stellite alloy),as a kind of Co-based wear-resistant alloy,is widely used in turbine engines and other high temperature sliding contact parts due to its low friction coefficient and good wear resistance at high temperature.The high temperature tribological behavior of CoCrW alloy determines the service life,safety and stability of high temperature sliding contact parts.According to the Fe-based,Co-based and Ni-based superalloy,a hard and smooth compacted oxide layer,called glaze layer,is formed on the alloy surface by the synergistic effect of the high-temperature oxidation and tribological behavior,which improves the tribological properties of alloy at high temperature during the wear process.Many studies have indicated that the ambient temperature has a significant impact on the tribological properties of Co-based alloy.As a new powder metallurgy technology,spark plasma sintering(SPS)has the advantages of a fast heating rate,low sintering temperature,and short sintering time.However,there are few studies on the high temperature tribological properties of Co-based alloy prepared by SPS.This work aims to investigate the microstructure and high temperature(400-800℃)tribological properties of CoCrW alloy prepared by spark plasma sintering(SPS).The high temperature tribological properties of SPSed CoCrW alloy at 400-800℃ was tested by reciprocating friction and wear machine and the wear rates were measured by white-light interferometer.The microstructure,phase constitution and element distribution of the CoCrW alloy,wear scars and debris,were investigated by SEM,EDS,EBSD,Raman spectra and EPMA.Meanwhile,the formation and evolution mechanism of the glaze layer were clarified.The results indicated that the SPSed CoCrW alloy had uniform microstructure,which consisted ofγCo,εCo and Cr7C3.At the same time,Cr_(7)C_(3) dispersed uniformly inside the matrix of the alloy,played an important role in inhibiting grain growth during sintering.Serious abrasive wear occurred at 400℃ on account of insufficient o

关 键 词：CoCrW合金 显微组织 高温摩擦学 高温氧化 釉质层 放电等离子烧结 

分 类 号：TH117[机械工程—机械设计及理论]