PREPARATION AND MECHANICAL-PROPERTIES OF SIC-AIN CERAMIC ALLOY

Fine-grained SiC-AlN ceramic alloys were synthesized by the reaction of silicon nitride and aluminium nitride powders with additions of carbon and CaO. X-ray diffraction and STEM-EDX analysis showed that they are single phase solid solutions. The SiC-AlN alloys were sintered without additives to full density by hot isostatic pressing at 2173 K and 200 MPa for 2 h. The flexural strength, microhardness and fracture toughness were measured and it was found that SiC-AlN alloys have double the strength and slightly higher fracture toughnesses than conventional monolithic SiC.