Characterization of Liquid Phase Sintered SiC Ceramics with Oxide Additive Materials

摘要

This paper dealt with the fabricating process of liquid phase sintered (LPS) SiC ceramics containing the oxide additives of Al_2O_3 and Y_2O_3, in conjunction with the evaluation of their mechanical properties. LPS-SiC ceramics was sintered at the temperature of 1820 ℃ under an applied pressure of 20 MPa and a pressure holding time of 2 hour. A commercial SiC powder with an average size of about 0.3 urn was used as a starting powder. LPS-SiC ceramics with additive composition ratios of 1.5 and 2.3 (Al_2O_3/Y_2O_3) represented an excellent density of about 3.2 Mg/m~3. LPS-SiC ceramics had a flexural strength of about 800 MPa and a fracture toughness of about 8.0 MPa·m~(0.5) at an additive composition ratio (Al_2O_3/Y_2O_3) of 1.5.