Phase Relation in SiC-Al₄C₃-B₄C System at 1800°C

Abstract

The phase relation in SiC-Al₄C₃-B₄C system at 1800°C was studied experimentally. Three complex carbides, Al₄SiC₄, Al₄Si₂C₅ and Al₈B₄C₇ were found in the system and liquid phase was formed around Al₈B₄C₇ at that temperature. The aluminum silicon carbide, Al₄Si₂C₅ showed a tendency to appear clearly in a boron containing pseudo-ternary system, SiC-Al₄SiC₄-Al₈B₄C₇, rather than SiC-Al₄C₃ binary system, and the compound is considered to be unstable in the binary system at 1800°C. Compatible triangles are supposed to be SiC-B₄C-Liq., SiC-Al₄SiC₄-Liq. and Al₄SiC₄-Al₄C₃-Liq. The stability of Al₄Si₂C₅ in the system leaves some uncertainty.