抄録
WC and WC-4.31wt%Co powders were sintered in graphite capsule under conditions of 5.8 GPa and 1300-1800°C. WC powder was compacted at 0.4 and 5.5 GPa and then sintered at 3×10-5 Torr and 1500-1700°C. The maximum hardness and relative density of WC obtained by high pressure and high temperature sintering at 1400-1500°C were 2550 kg/mm2 and 96%, respectively. A remarkable grain growth with its own habit was observed above 1600°C. It is suggested that CO or CO2 gas is captured in the sintered body and these gases are closely related to the grain growth. It is also shown in vacuum sintering that the WC powder compacted at 5.5 GPa is improved in its sinterability compared with that compacted at 0.4 GPa. This is due to the increase in the initial density and the strain introduced to the WC particles.
