化学包裹粉工艺制备粗晶粒WC-Co硬质合金

WC-Co cemented carbide from porous spumous cobalt enwrapped WC powders by chemical route

以费氏粒度为8.06μm的WC粉与Co(NO3)2·6H2O为原料,采用N(CH2CH2OH)3(TEA)为还原剂制备WC-12%Co(质量分数)包裹粉,以包裹粉为原料制备WC-12%Co硬质合金。采用扫描电镜观察包裹粉与合金中WC晶粒的立体形貌,采用X射线衍射仪分析粉末的物相组成,采用比表面积分析仪分析TEA还原产物多孔泡沫Co的比表面积,采用金相显微镜观察合金的组织结构。结果表明:包裹粉中Co为纯fcc高温相结构,呈多孔泡沫状纳米组装结构形式包裹在WC粉末表面;WC-12%Co合金组织结构均匀,平均晶粒度为4.8μm,WC晶粒结晶完整、呈规则多面体形状。

The WC-12%Co（mass fraction） cemented carbide with an average grain size of 4.8 μm and homogeneous microstructure was prepared from porous spumous cobalt enwrapped tungsten carbide powders produced by a novel chemical route.The tungsten carbide powder with Fisher sub-sieve sizer granularity of 8.06 μm and cobaltous nitrate hexahydrate were used as the starting materials,and the triethanolamine（TEA） was used as the reducer.The phase constitutes and morphology of the powders were investigated by X-ray diffractometry and scanning electron microscopy,respectively.BET specific surface area analyzer was used to analyze the porous spumous cobalt reduced with TEA.The microstructure of WC-Co cemented carbide was observed by metallographic microscopy.The results show that,in the cobalt enwrapped WC powders,cobalt exists in pure face centered cubic structure in the form of nano particles assembly.The tungsten carbide grains in the alloy are characterized by regular polyhedron morphology and high degree of crystalline perfection.