Mechanical properties and thermal shock resistance of Si2BC3N ceramics with ternary Al4SiC4 additive

Dense Si2BC3N ceramics were prepared through SPS sintering the amorphous Si2BC3N and Al4SiC4 powders obtained from mechanical alloying. The phase compositions, microstructures, and mechanical properties, as well as the thermal shock resistance were investigated. In addition, evaluations of oxidation and the ablation resistance were also preceded. The results show that Al4SiC4 phase can be detected at 1200 and 1400 °C under pressureless sintering. However, Al4SiC4 can be decomposed to AlN and SiC phases under higher temperatures. As for the bulk Si2BC3N ceramics, the Al4SiC4 additive induce the development of turbostratic BN(C) plates and improve the relative density consequently. Besides, the Al4SiC4 plates are embedded in the matrix of ceramics. Therefore, the mechanical properties and thermal shock resistance are improved apparently with the addition of additive. Meanwhile, the additive containing composites have superior ablation resistance than the pristine Si2BC3N ceramics due to their higher relative density.