摘要
利用真空原位还原碳化反应合成超细/纳米WC-Co复合粉末,通过添加一定量Cr获得WC-10Co-4Cr复合粉末,经团聚造粒获得喷涂用复合粉末喂料,采用超音速火焰(HVOF)喷涂系统制备出超细/纳米结构的WC-10Co-4Cr涂层。利用X射线衍射仪,扫描电子显微镜和透射电子显微镜对涂层的物相、显微组织结构、元素分布特征等进行了系统表征,并对涂层耐磨性、耐蚀性进行了测试分析。结果表明:基于原位反应合成WC-Co复合粉制备的超细/纳米结构WC-10Co-4Cr涂层具有较好的耐磨性和耐腐蚀性。涂层以WC为主相,含有非晶结构的粘结相Co(Cr),同时存在少量六方晶体结构的W_2C相和非晶复相W_2C+Co(Cr)。对涂层中元素Co和Cr的分布进行了量化分析,得到其从WC晶粒到相界到共晶区再到Co区的变化规律。结合WC-10Co-4Cr复合粉末和超音速火焰喷涂工艺的特点,阐释了Cr在WC-10Co-4Cr涂层分布状态的形成原因,并讨论了对涂层性能的影响。
The ultrafine/nanostructured WC-Co composite powder was synthesized by reduction and carburization reactions, and then Cr was added to the powder to obtain WC-10Co-4Cr composite powder; afterwards, the WC-10Co-4Cr composite powder was agglomerated to prepare the composite powder feeding that was used in spraying; finally the ultrafine/nanostructured WC-10Co-4Cr coating was prepared by high velocity oxygen fuel（HVOF）. The phases, elemental distribution and microstructure of the coating were characterized by X-ray diffraction（XRD） and transmission electron microscope（TEM）, and then the wear resistance and corrosion resistance of the coating were tested. The results show that the main phase of the coating is WC, the binding phase of amorphous structure is Co（Cr）, and there is a little W2C phase of hexagonal crystal structure and W2C＋ Co（Cr） multiphase of amorphous. The change rule of WC grain was obtained from phase boundary to eutectic area to Co area by the quantitative analysis of distribution of Co and Cr element in coating. Combined WC-10Co-4Cr composite powder and the process characteristics of HVOF, we explained the causes of Cr distribution in the WC-10Co-4Cr coating, and discussed its influence on the coating performance.
出处
《稀有金属材料与工程》
SCIE
EI
CAS
CSCD
北大核心
2017年第3期704-710,共7页
Rare Metal Materials and Engineering
基金
国家高技术研究发展计划("863"计划)(2013AA032001)
北京市自然科学基金重点项目(2131001)
北京市自然科学基金项目(2154045)
