超细粉末低温超音速火焰喷涂WC-10Co-4Cr涂层及其干摩擦磨损性能

发布时间：2019-03-15 13:40

【摘要】：为了进一步提高超细粉末WC喷涂层的性能,以5~15μm的超细WC-10Co-4Cr粉末为材料,分别采用低温超音速火焰喷涂(LT-HVOF)和超音速火焰喷涂(HVOF)技术在316L不锈钢表面制备WC涂层。通过聚焦离子束(Focused ion beam,FIB)对WC-10Co-4Cr粒子剖面形貌进行了原位切割并分析,利用SEM形貌、EDS谱和摩擦磨损试验对涂层的显微结构和干摩擦磨损性能进行了表征。结果表明:HVOF的高焰流温度使超细WC-10Co-4Cr粉末的粘结相充分熔融,WC硬质相溶于粘结相或发生脱碳,形成Cox(WC)y脆性相和W2C相,另外因Cr较低的表面张力使涂层内界面存在富Cr带,而LT-HVOF涂层没有富Cr带;LT-HVOF涂层的摩擦系数和磨损率分别为0.632 2,1.560×10-5mm3/(N·m),均低于HVOF涂层;2种WC涂层的磨损形式均以磨粒磨损为主,HVOF涂层中的富Cr带在载荷作用下形成裂纹并易于沿其扩展,造成涂层较大块剥落,降低了WC涂层的耐磨性能。
[Abstract]:In order to further improve the properties of ultra-fine powder WC spray coating, the ultra-fine WC-10Co-4Cr powder of 5 ~ 15 渭 m was used as the material. WC coatings were prepared on 316L stainless steel by low temperature supersonic flame spraying (LT-HVOF) and supersonic flame spraying (HVOF). The profile of WC-10Co-4Cr particles was in situ cut and analyzed by focused ion beam (Focused ion beam,FIB). The microstructure and dry friction and wear properties of the coatings were characterized by SEM morphology, EDS spectra and friction and wear tests. The results show that the bonding phase of ultra-fine WC-10Co-4Cr powder is fully melted by the high flame temperature of HVOF, and the hard phase of WC is dissolved in the bonding phase or decarburized, resulting in the formation of Cox (WC) y brittle phase and W2C phase. In addition, because of the low surface tension of Cr, there are Cr-rich bands in the inner interface of the coatings, but there is no Cr-rich bands in the LT-HVOF coatings. The friction coefficient and wear rate of LT-HVOF coating were 0.632 2,1.560 脳 10-5mm3/ (N 路m),) lower than that of HVOF coating, respectively. The wear forms of the two kinds of WC coatings are mainly abrasive wear. The Cr-rich bands in the HVOF coatings form cracks under loading and easily propagate along them, which results in the large spalling of the coatings and decreases the wear resistance of the WC coatings.
【作者单位】：广东省新材料研究所现代材料表面工程技术国家工程实验室广东省现代表面工程技术重点实验室;华南理工大学材料科学与工程学院;
【基金】：国家科技支撑项目(2014BAF08B03) 广东省科技计划项目(2015B070701024) 科技部科研院所项目(2014EG115005) 广东省省院平台建设项目(2016GDASPT-0206和2016GDASPT-0317)资助
【分类号】：TG174.4

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