Effects of Microwave Sintering Temperature and Holding Time on Mechanical Properties and Microstructure of Si(3)N(4)/n-SiC ceramics

The n-SiC (nanometer SiC) is added to be the additive in order to improve the mechanical performance of Si(3)N(4) ceramics. A microwave sintered the ceramics at different temperature and holding times. The results shows that the Si(3)N(4)/n-SiC ceramics (85 wt% Si(3)N(4) + 5 wt% n-SiC + 5 wt% Al(2)O(3) + 5 wt% Y(2)O(3)) have the best mechanical properties at 1600 °C, which is beneficial to the densification and β-Si(3)N(4) phase formation for 10 min: the density, hardness, and fracture toughness were 97.1%, 14.44 GPa, and 7.77 MPa·m(1/2), which increased by 2.8%, 7.0%, and 13.1%, respectively, when compared with the ceramics (90 wt% Si(3)N(4) + 5 wt% Al(2)O(3) + 5 wt% Y(2)O(3)).