Preparation of Directionally Solidified B₄C–TiB₂–SiC Ternary Eutectic Composites by a Floating Zone Method and Their Properties

Abstract

Directionally solidified B₄C–TiB₂–SiC composites were prepared by a floating zone method using B₄C, TiB₂ and SiC as starting materials. The B₄C–TiB₂–SiC system was ternary eutectic whose eutectic composition was 51.2B₄C–8.1TiB₂–40.7SiC (mol%). The ternary eutectic composite showed a lamellar microstructure where B₄C(104), TiB₂(100) and SiC(111) planes were perpendicular to the growth direction. The Vickers hardness of the B₄C–TiB₂–SiC ternary eutectic composite was 28 to 32 GPa. The electrical conductivity was 6 to 9×10⁴ Sm⁻¹, and the thermal conductivity was 35 to 45 WK⁻¹m⁻¹ in the temperature range from 298 to 1100 K.