The effect of aluminum additive on pressureless sintering of SiC

This study was carried out to investigate the effect of Al additive amount on the microstructure development and room temperature mechanical properties of pressureless sintered silicon carbide. Different amounts of Al containing of 1, 2.5, 5, 10, and 15 wt% were added to the base material and pressureless sintering was conducted at 1950 °C for 1 h under argon atmosphere. The formation of the Al4SiC4 phase during conventional sintering was confirmed by X-ray diffraction (XRD) analysis. Microstructure, crystal phases, and density evolution were studied and correlated to Al additions and pre-sintered proceedings. The obtained results show that the addition of Al not only improves sinterability at lower temperature, but also enhances densification and hardness of SiC samples (3.05 g/cm3 and 26.9 GPa respectively).