Preparation, properties and microstructure of Si3N4/TiC nanocomposite ceramics

By adding Si3N4 and TiC nanoparticles, the Si3N4/TiC nanocomposite ceramics were fabricated with Al2O3 and Y2O3 as additives. The results show that well dispersed composite powder was obtained by adding dispersant and adjusting pH values of suspensions. The nano-sized particles refined the matrix grains and promoted the forming of duplex microstructure. As a result, the density and mechanical properties were improved also. With 10% mass fraction Of Si3N4 and 15% of TiC, the nanocomposite ceramics show the best mechanical properties. The flexural strength, fracture toughness and Vicker's hardness were 1 088 MPa, 7.5 MPa(.)m(1/2) and 16.95 GPa, respectively. SEM and TEM analyzed the microstructures of materials.