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

Abstract

Abstract (Ti1-xNbx)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\xa0°C in air. The niobium content was found to exhibit a remarkable influence on the oxidation resistance of (Ti1-xNbx)C solid solutions. An optimization of oxidation resistance was achieved in (Ti0.8Nb0.2)C. After oxidation at 1000\xa0°C for 4\xa0h, the oxidation layer thickness of (Ti0.8Nb0.2)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 TiO2 phase in the oxidation layer of (Ti0.8Nb0.2)C. The (Ti,Nb)O2 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.