Sintering of WC-Co powder with nanocrystalline WC by spark plasma sintering

A 92WC-8Co powder mixture with 33 nm WC grains was prepared by strengthening ball milling and was then sintered by spark plasma sintering (SPS) at 1000- 1200 degrees C for 5-18 min under 10-25 kN, respectively. Movement of the position of low punch shown shrinkage of the sintered body began above 800 degrees C. The shrinkage slowly rose as the temperature rose from 800 to 1000 degrees C and then quickly rose at above 1000 degrees C and then gradually rose at above 1150 degrees C. The densities of the samples increased with an increase in sintering temperature, rapidly below 1100 degrees C, and then gradually above 1100 degrees C. WC grains grow gradually with increasing sintering temperature. The powder was sintered to near full density at 1100 degrees C for 5 min under 10 kN. The best result of the sample with 275 = WC grains and no pores was obtained at 1150 degrees C under 10 kN for 5 min. The research found the graphite die had a function of carburization, which could compensate the sintered body for the lack of carbon, and had the normal microstructure.