Study on the Thermal Shock Resistance of Si_3N_4/TiC Nanocomposite Ceramic Tool Materials

摘要

By adding nano Si_3N_4 and nano TiC particles into the micro Si_3N_4 matrix, the Si_3N_4/TiC nanocomposite ceramics were fabricated via hot pressing technique with Al_2O_3 and Y_2O_3 as sintering additives. The thermal shock resistance of Si_3N_4/TiC nanocomposites were investigated by means of indentation-quenching and quenching-retained strength testing methods. The results revealed that the composite containing 10 wt.% nano Si_3N_4 particles and 15 wt.% nano TiC nano particles was possessed of the highest thermal shock resistance, with its critical temperature difference being 700～750℃. The toughening and strengthening mechanisms by the nano particles addition are deem to be the essential course for the improved thermal shock resistance.