Effects of Si source and high gravity on combustion synthesis of Ti ₃ SiC ₂ in air

Combustion synthesis of Ti3SiC2 was carried out in air with Si3N4, SiC, and Si as Si sources respectively, and the effect of Si source on the phase composition of the products was investigated. With Si3N4 as Si source, the major product was TiCxN1−x and no Ti3SiC2 was synthesised. When SiC and Si were used, Ti3SiC2 was synthesised. Such effect of Si source is thought to be connected with the formation mechanism of Ti3SiC2, where the presence of a Ti–Si melt is required. The combustion synthesis was also performed under high gravity condition instead of common gravity. The apparent density of the product prepared under high gravity was ∼60% higher than that obtained under normal gravity. It is proposed that, the high gravity can facilitate the permeation of Ti–Si melt and enlarge the interface between the melt and carbide phases, which is helpful for the formation of Ti3SiC2.