本文采用亚微米WC粉和纳米Co粉、亚微米WC粉和高能球磨后具有纳米晶组织的微米级Co粉这两种具有不同粒径匹配的混合粉末作为原料粉末，利用放电等离子烧结（SPS）技术制备超细晶WC-10Co硬质合金。对不同原料粉末的SPS过程及烧结试样的显微组织和性能进行了系统的对比分析。实验结果表明，以两种混合粉末为原料均获得了平均晶粒尺寸在200nm以下的超细硬质合金材料，其中，采用亚微米WC粉和高能球磨的微米级Co粉利用SPS技术制备的材料相对密度达到98%以上，硬度达到HRA94.5，断裂韧性达到13.50MPa•m1/2，表明具有优良的综合性能。而采用亚微米WC粉和纳米Co粉利用SPS技术制备出的超细晶硬质合金的组织均匀性和性能较差。根据SPS技术的特殊烧结机理，对采用不同粒径匹配和结合状态的WC和Co混合粉末的SPS致密化机制进行了分析。
The ultrafine WC-10Co cemented carbides were prepared by spark plasma sintering (SPS) using sub-micron WC/nano Co and sub-micron WC/micron Co with nanocrystalline structures as the raw powders in this paper. The SPS process, microstructure and properties of the sintered samples were investigated. The ultrafine cemented carbides with mean grain size of less than 200nm were prepared using the two kinds of raw powders. The sintered sample using sub-micron WC/micron Co powders as raw materials has a relative density of 98%, hardness of HRA94.5 and fracture toughness of 13.50MPa•m1/2, which indicate an very good combination of mechanical properties. While the sample sintered using the sub-micron WC/nano Co powders as raw materials has lower properties. The densification mechanisms of sintering the two kinds of WC/Co mixed powders were analyzed based on the special SPS mechanism.
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