Oxidation behaviors of (Ti1-xNbx)C ceramic solid solutions

(Ti 1-x Nb x )C (x=0, 0.2, 0.5 and 0.8) ceramic solid solutions were prepared by spark plasma sintering and their oxidation behaviours were investigated at 1000 °C in air. The niobium content was found to exhibit a remarkable influence on the oxidation resistance of (Ti 1-x Nb x )C solid solutions. An optimization of oxidation resistance was achieved in (Ti 0.8 Nb 0.2 )C. After oxidation at 1000 °C for 4 h, the oxidation layer thickness of (Ti 0.8 Nb 0.2 )C is less than 1/4 of the oxidation layer thickness of monolithic TiC. The higher oxidation resistance can be ascribed to the presence of Nb-doped rutile TiO 2 phase in the oxidation layer of (Ti 0.8 Nb 0.2 )C. The (Ti,Nb)O 2 phase suppressed the abnormal grain growth and the formation of cracks in the oxide layer, more importantly, it could effectively sluggish the outward diffusion of titanium during oxidation.