Effect of sintering atmosphere on the densification behavior of hot pressed TiN ceramics

Using nano-sized starting powders, TiN ceramics were hot pressed under different sintering atmospheres, which were nitrogen, argon and vacuum (5 Pa). The effects of sintering atmosphere on the densification process and microstructures of TiN ceramics were investigated. At 1500 °C, ceramics densified under vacuum demonstrated higher density compared with nitrogen and argon, owing to the high nitrogen vacancy concentration which came from the dissociation of TiN under vacuum circumstance. At 1600 °C, however, the densification process under vacuum will be hindered because of the decomposition of TiN. Combining a lower sintering temperature, smaller grain size and higher grain boundary concentration, the argon atmosphere is more suitable for fabrication of TiN ceramics as nuclear materials.