Sintering behavior and mechanical and thermal shock properties of silicon nitride-boron nitride composites

Si3N4/BN composites were formulated and prepared by pressureless sintering of mixed and granulated Si3N4 and BN powders using TiB2, Al2O3, Y2O3 and SiO4Zr as sintering aids. Compositions ranged from 5 to 30% BN. Several dispersant agents were also employed. Sintering was performed using a high temperature dilatometer equipped with a graphite furnace. Materials obtained were characterized mechanically through Vickers microhardness, mechanical strength, fracture toughness, thermal shock measurements and creep behavior. (orig.)