Sintering behavior, microstructure and mechanical properties of silicon carbide ceramics containing different nano-TiN additive

摘要

Silicon carbide ceramics with nano-TiN additive were liquid phase sintered at 1950 °C for 15 min and subsequently sintered at 1850 °C for 1 h. The influence of the additive content on the sintering behaviors of silicon carbide ceramics was investigated by analyzing sintering behaviors, phase compositions, microstructure observation and mechanical properties testing. The results show that the addition of nano-TiN particles restrains the densification of silicon carbide ceramic, inhibits the grain growth of ceramic. And the reactions of TiN with SiC and Al_2O_3 to form new phases of TiC and AlN may benefit the silicon carbide ceramics in a certain range of nano-TiN addition. The silicon carbide ceramic with 5 wt.% of nano-TiN possesses high densification, uniform microstructure and superior mechanical properties. The toughening mechanism of nano-TiN on silicon carbide ceramic mainly comes from thermal residual stresses, crack deflection and crack bridging.