Preparation and characterization of Cr/CrC multilayer on γ-TiAl alloy by the double glow plasma surface alloying technology

Hard ceramic and ductile metal materials combined in multilayered structures provide superior wear and oxidation resistance to the single layer, which has been applied extensively to components subjected to high-temperature oxidation and wear. In this paper, the oxidation and wear properties of Cr/CrC multilayer coating obtained on γ-TiAl alloy by an emerging technology, that is double glow plasma surface alloying technology, were reported. Sliding wear and oxidation tests were performed on Cr/CrC multilayer as well as on chromising reference coating. The friction coefficients of Cr/CrC multilayer at room and high temperature were 0.2 and 0.175 respectively, about only 22.2% and 35% of the γ-TiAl substrate. The Cr/CrC multilayer oxidized approximately parabolically, with lower oxidation rate than the chromising coating. The oxidation mechanism of the Cr/CrC multilayer was mainly dominated by carbide oxidation and dense Cr2O3 scale oxide development.