Making of sintered silicon carbide bodies

摘要

Pressureless sintering is used to densify silicon carbide based ceramics using a compound comprising transition metal oxides and aluminum oxide at temperatures in excess of 1850 DEG C. The resulting sintered body has a density greater than 95% of its theoretical density, flexural strength in excess of 560 MPa and fracture toughness of 7.2 MPa.m1/2. The method consists of sintering and conversion of transition metal oxides into carbides in one step operation. Practically any transition metal oxide can be used. The sintered ceramic bodies made by the present invention consist of silicon carbide matrix phase and Al2O3 and transition metal carbide phases.