The effect of Ta on oxidation resistance of in-situ TiC/Ni composites

In-situ TiC/Ni composite with Ta element was fabricated by reactive sintering. Ta element solid solubilizes in TiC particles and Ni matrix. The addition of Ta reduces the oxidation rate of TiC at initial stage of oxidation, and suppresses the outward diffusion of Ti atom and inward diffusion of O atom after the formation of oxide scale, leading to the decrease of TiO2 and NiTiO3 content in oxide scale. The oxidation resistance of composites is optimized. Ta element improves the electrical conductivity of composites at 800 degrees C by increasing electron concentration in oxide scale and reducing the thickness of oxide scale.