Ballistic performance of liquid-phase sintered silicon carbide

The ballistic performances of liquid-phase sintered silicon carbide (SiC) specimens prepared by pressureless sintering were evaluated. Solid-state sintering additives were also used in preparation of additional SiC specimens for comparison purposes. SiC specimens prepared by adding solid-state sintering additives were also prepared for the purpose of comparison. With the addition of 10–15 wt% of Al2O3 and Y2O3, the strength and toughness of the liquid-phase sintered SiC (LSC) were higher than those of solid-state sintered SiC (SSC). Nevertheless, the hardness of LSC specimen tended to be lower. However, LSC specimens sintered at 1875 °C can pass the NIJ Level IV test. The microstructure observation provides direct evidence of the importance of hardness and toughness regarding ballistic performance. A performance index, the hardness/density ratio, is proposed to rank the ballistic performance on ceramics used for personnel armor applications.