(W,Mo)C粉末及(W,Mo)C-Co基硬质合金制备及性能

以WC-M02C-C粉末混合物为原料,通过热压反应的方法在2000℃的烧结温度下成功制备得到了“MoC”质量分数为5%和15%的(Mo,W)C粉末.并利用这些粉末分别在Ar和N2气氛中烧结制备了(Mo,W)C-10%Co-VC-Cr3C2硬质合金.检测分析了合金的硬度HV30、断裂韧性Kc、密度和磁性;并通过DTA分析测定了硬质合金的液相形成温度.结果表明,使用热压法获得的(Mo,W)C粉末制备(Mo,W)C-10%Co-VC-Cr3C2硬质合金,可以获得“MoC”质量分数为15%的具有低孔隙率的合金产品.当“MoC”质量分数为5%时,可以制备得到完全致密的硬质合金,其硬度HV30和断裂韧性K1c均优于同粘结相含量的WC-Co硬质合金.在(Mo,W)C基硬质合金的微观结构中,发现了类似于金属陶瓷中的芯-环结构的硬质相颗粒.根据DTA曲线可以发现,与WC-Co硬质合金相比,(Mo,W)C基硬质合金具有较低的液相形成温度.

Preparation and properties of(Mo,W)C powders and(Mo,W)C-Co cemented carbides

(Mo,W)C powders and hardmetals with(Mo,W)C as the hard phase were prepared and their microstructure as well as properties were studied.(W,Mo)C powders with 5wt%and 15wt%"MoC”used in this work were obtained by reaction sintering WC-Mo2C-C powder mixtures at 2000℃using hot-pressing.(Mo,W)C-10%Co-VC-Cr3C2 hardmetals were then fabricated by sintering in Ar and N2 atmosphere,separately.Some typical characteristics of the hardmetals,such as hardness HV30,Palmqvist-Shetty density and magnetic properties were recorded.The liquid phase formation temperatures of(Mo,W)C-10%Co-VC-Cr3C2 hardmetals were also determined by means of DTA analysis.The results show that upon use of(Mo,W)C powders obtained by hot-pressing method,even hardmetals with 15%"MoC"could be prepared with low porosity."MoC"additions of up to 5wt%yielded completely dense hardmetals with high HV30 and Klc.In the microstructure of doped(Mo,W)C based hardmetals rounded grains with core-rim structure were found similar to that of cermets.According to DTA curves,it can be found that compare to WC-Co hardmetals,(Mo,W)C based hardmetals have lower liquid phase formation temperatures.