Preparation of Ti2AlN by reactive sintering

Resumo

Reactive sintering of 2Ti–AlN mixtures at T = 1300°C for τ = 2 h in an argon atmosphere was used to prepare Ti₂AlN containing below 1 wt % TiN and exhibiting a laminate structure typical of MAX compounds. At lower values of T and τ, the TiN content of products increased. Sintering in vacuum yielded a material containing up to 20 wt % TiN. Contrary to our expectations, mechanical activation of green blends was found to increase the TiN content of sintered materials, due to intensification of thermal dissociation of AlN and elimination of Al, which shifts equilibrium toward two-phase Ti₂AlN–TiN composite. Relative density of green compacts was found to produce little or no influence on phase composition of products.