Fabrication of highly dense Ti₃SiC₂ ceramics by pressureless sintering of mechanically alloyed elemental powders

Abstract

Pressureless sintering of Ti₃SiC₂ ceramics has been investigated by using mechanically alloyed elemental Ti, Si and C powder mixture as the starting materials. It has been found that mechanical alloying enhanced both the formation of Ti₃SiC₂ phase and the densification during sintering process. Highly dense Ti₃SiC₂ ceramics with a relative density up to 99% and a phase purity of ∼80% Ti₃SiC₂ (TiC_x as the secondary phase) were obtained by sintering the mechanically alloyed powders at relatively low temperatures near 1773 K in an argon atmosphere of 0.1 MPa. The physical properties of the present pressureless-sintered Ti₃SiC₂-based ceramics are comparable to those of nearly single phase Ti₃SiC₂ ceramics fabricated by the reactive hot-isostatic pressing (HIP) that had been used so far.