Preparation of superfine WC-Co cemented carbides by spark plasma sintering process

Spark plasma sintering (SPS) process was used to prepare superfine WC-10Co cemented carbides. The effects of sintering temperature and sintering atmosphere on the microstructure and properties of WC-Co cemented carbides were investigated. The results show that the density of the compacts increases with increasing sintering temperature. However the composition of the compacts is different from that of the starting powders because of the evaporation of Co, and the evaporation rate of Co increases with the increase in sintering temperature and the decrease in atmosphere pressure. It is found that the composition of the compacts can be very close to that of the starting powders by increasing the atmosphere pressure. The mass fraction of Co in the compacts sintered at 1 250℃ for 5min under 30MPa in the argon atmosphere of 200Pa is 10.02%, and the density and hardness are 14.62g·cm^-3 and HRA 92.4, respectively.