Development of New Processing Technology which Realizes in-situ Dispersion of Nano-Particles and Whiskers in Ceramic Matrix

摘要

Development of new Complex Precipitation Reaction(CPR); i.e., positive use of gas phase and/or liquid phase in solid-solid reaction, realizes in-situ dispersion of nano-sized particles and whiskers in ceramic matrix. The application of the CPR process in Si-TiC-TiO_2 system has proved to be suitable for dispersing finer particles in Si_3N_4 matrix more homogeneously than the Conventional Reaction Bonding(CRB) process in Si-TiN system. For high temperature applications, further investigation was made on the precipitation of SiC particles and whiskers in Si-SiO-C and Si_3N_4-C systems by the CPR process and successfully dispersion of SiC particles and whiskers in Si_3N_4 matrix was obtained. Nano-sized particles of less than 200nm and whiskers of around 5 μm were homogeneously dispersed in Si_3N_4 matrix. Bending strength of 700MPa and fracture toughness of 8.6MPa·m~(1/2) were achieved. These results indicate that the CPR process is effective for dispersing nano-particles and whiskers in ceramic matrix, resulting in compatibility of high strength and high toughness.