复合添加晶粒长大抑制剂对WC-12Co超细晶硬质合金涂层性能的影响

Effect of Combined Addition of Grain Growth Inhibitors on the WC-12Co Coating

摘要:

本文利用真空原位还原碳化反应合成超细WC-12Co复合粉末,通过复合添加不同含量的晶粒长大抑制剂VC和Cr₃C₂,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WC-12Co涂层。利用X射线衍射和扫描电镜对涂层的物相、显微组织结构等进行了系统表征,并对涂层耐磨性进行了测试分析。结果表明：WC-12Co涂层中WC晶粒的平均尺寸,随着晶粒长大抑制剂的增加而减小,且抑制剂的添加使涂层的摩擦系数降低；当复合添加抑制剂总含量为1.0wt.%时,WC-12Co涂层的显微硬度达到最大值1367 HV_0.3,且涂层的磨损速率最低；随抑制剂含量进一步增加,WC-12Co涂层的显微硬度逐渐降低,磨损速率增加,涂层的耐磨性降低。

Abstract:

_{:The WC-12Co composite powder was synthesized by reduction and carburization reactions. With adding various contents of combined grain growth inhibitors (GGI) VC and Cr3C2 into theWC-12Co compositepowder, the effects of the GGI addition on the phase constitution, microstructure and mechanical properties of the coating havebeen investigated by X-ray diffraction (XRD)and scanning electron microscopy (SEM)respectively. The result shows thatthat with the content of GGI increasing in the composite powder, the abnormal grain growth disappears and homogeneous ultrafine grain structure forms, the coefficient of friction of the coating reduces. When the total amount of inhibitor is added in combination 1.0wt.%, the maximum hardness of WC-12Co coating is 1367 HV0.3, and the wear rate of the coating isthe lowest.Further increasing the content of inhibitor, the wear rate of the coating increases, the hardness and the wear resistanceof the coatingdecreases.}