Low temperature sintering of Si 3 N 4 ceramics by spark plasma sintering technique

Low temperature sintering of α‐Si3N4 matrix ceramics was developed in the present study using 4 wt‐%MgO together with Al2O3 or AlPO4 as the sintering additives and spark plasma sintering technique. The results suggested that α‐Si3N4 ceramics could be densified at low sintering temperature by adjusting both the sintering temperature and sintering additive content. For low temperature sintered α‐Si3N4 ceramics, using MgO and Al2O3 as the sintering additives, the densification is not complete at a temperature lower than 1600°C, and the mechanical strength is <200 MPa. When MgO and AlPO4 were used as the sintering additives, the increase in AlPO4 content not only declines the sintering temperature but also promotes the mechanical property of the sintered Si3N4 ceramics. It was the AlPO4 phosphate binder that played a significant role in low temperature sintering of Si3N4 ceramics.