一种超细无粘结相WC硬质合金的制备

以粒度0.2μm纯WC粉末为原料,经球磨处理在1230°C烧结,890MPa热压制备高硬度、高致密度的超细无粘结相WC硬质合金.对合金的相组成、致密度、显微硬度及微观形貌进行了分析.结果表明:未经球磨处理的WC粉末烧结后样品的硬度低、致密度差,有缺碳相W相产生；经过球磨处理的WC粉末在烧结热压后样品硬度为2157HV,是未球磨样品硬度的15倍,致密度达到95.1％；断口可观察到明显的解理断裂特征；为抑制脱碳相的产生,对纯WC粉末加入单质碳,当配碳量为0.35％时,XRD结果显示样品全部为WC相,硬度与致密度分别提高至2480 HV和98％.

Preparation of a Ultra-Fine Binderless WC Cemented Carbide

Pure WC powder with an average diameter of 0.2 μm was used to prepare ultra-fine binderless WC cemented carbide by sintering at 1230℃ followed by hot pressing at 890 MPa,and the phase composition, density,Vickers hardness and microstructure of the WC cemented carbide were studied.The results show that the WC cemented carbide made of WC powder without ball milling exhibits lower hardness and density compared with that made of milled powder.The hardness of the latter is HV 2157,15 times of that of the former, and its density is 95.1%.The morphology of fracture surface is characterized by cleavage fracture.In order to inhibit the decarburizing reaction,carbon element was added in WC powder,and XRD analysis reveals that pure WC is obtained with a 0.35% carbon addition resulted in the hardness of HV 2480 and density of 98% for the sintered WC cemented carbide.