Tape Casting, Pressureless Sintering, and Grain Growth in Ti3SiC2 Compacts

In this work we demonstrate that fine Ti₃SiC₂ powders can be tape-cast and/or cold-pressed and pressureless-sintered in Ar- or Si-rich atmospheres to produce fully dense, oriented microstructures in which the basal planes are parallel to the surfaces. Carbon- and/or Si-rich environments suppress grain growth. In the case of the tape casting, the C-residue from binder burnout results in small core grains relative to the surface grains that can grow significantly. When sintering in high Si activities, titanium silicide phases form at the grain boundaries that slow grain growth. Annealing the latter in Ar at 1600°C, for extended periods (30 h), rids the samples of these grain-boundary phases, which in turn results in grain growth. The advantage of the latter process is that the final grain size distribution is more uniform from surface to bulk.