Ballistic Properties of Pressureless Sintered SiC/TiB2 Composites

Abstract

Pressureless sintering of ceramics for armor applications offers the potential of greatly reduced cost and increased production volume. Previously it was shown that pure SiC could be made by pressureless sintering while achieving a ballistic performance slightly less than commercial SiC made by pressure-assisted densification (PAD). Additions of titanium diboride were made to pin the SiC grain size during pressureless sintering to achieve a final grain size closer to that found in PAD SiC and achieve improved ballistic performance. Silicon carbide/titanium diboride composites of various compositions were blended by various means, consolidated and pressureless sintered to near theoretical density. Additions of TiB 2 were ≤10% by volume and increased the density of the material by less than 3% over that of pure SiC. Variations in the mixing techniques yielded composites with a range of TiB 2 particle sizes. TiB 2 additions hindered SiC grain growth and the formation of elongated grains during high temperature pressureless sintering. The microstructure of the composites is documented and compared to commercially available SiC material. The SiC/TiB 2 composites demonstrated improved ballistic properties in Depth-of-Penetration (DOP) tests over pure, pressureless-sintered SiC material and approach that of SiC made by hot pressing.