Obtaining the Ni-TiC Composite Powder by the Carbidization of Titanium Nickelide

The goal of this study is to investigate the mechanism and kinetics of carbidization of the titanium nickelide powder, which allows one to obtain the Ni-TiC composite powder. It is established by experimental methods and theoretical analysis that, in the temperature range 1000–1200°C, this process proceeds in the internal mode with the decomposition of NiTi and with the formation of a nickel-based solid solution with dispersed titanium carbide particles distributed in it. It is shown that, with the carbon excess in the starting charge, the final product consists of a nickel matrix, including ∼3 at % carbon and traces of titanium, and particles of almost stoichiometric titanium carbide. With the deficiency of carbon in the starting charge, the Ni matrix contains ∼1.1 × 10−2 at % carbon and >0.65 at % titanium, while the particles of titanium carbide have the composition TiC0.5-TiC0.8. The suggested model of this process allows one to evaluate the time that the NiTi particles completely decompose and qualitatively describe the time dependence of the particle size of titanium carbide.