Preparation and thermal shock property of Si3N4 ceramic reinforced by orientation SiC whiskersL

A highly orientation SiC whisker reinforced Si_3N_4 composite was fabricated by fiber extrusion and hot-pressing technique, which SiC whiskers were unidirectional oriented in the ex- truded carrier fiber. Microstructure of the composites was observed by SEM. Whisker directions were image-processed to quantify SiC whisker orientation in the extruded fibers and the compos- ites. Effects of sintering temperature and SiC whisker content on the flexural strength and fracture toughness of the composites were investigated. The experimental results show that the flexural strength and fracture toughness of the orientation SiC whisker toughened Si_3N_4 composites are higher than that of the random SiC whisker toughened Si_3N_4 composites after thermal shock experiment, in temperature difference of 1000℃ and 500℃.