Abstract:
B4C/SiC pellets were prepared by warm pressing of polycarbosilane-coating boron carbide powder at the temperature of 300 ℃ under the pressure of 50 MPa, and cold isostatic pressing under the pressure of 800 MPa, respectively. The samples were then kept warm at 1 200 ℃ for 2 h in flowing Ar, with subsequent sintering for 3 h between 1 800 and 2 000 ℃ in vacuum. Relative densities, phases and microstructures of the multiphase ceramics were investigated. The results show that the multiphase ceramics prepared by warm pressing (WP) had higher density than that by cold isostatic pressing (CIP). The multiphase ceramics with maximum relative density was achieved after the warm pressing green bodies containing 15% SiC sintered for 3 h, and its relative density was more than 93%. The multiphase ceramics consisted of B4C and SiC and SiC phases distributed uniformly on the B4C particles interface.