Improvement of high temperature oxidation resistance of micro arc oxidation coated AlTiNbMo0.5Ta0.5Zr high entropy alloy

The present work is focused on forming micro arc oxidation (MAO) coating on AlTiNbMo0.5Ta0.5Zr refractory high-entropy alloys (RHEAs). The high temperature oxidation resistance of MAO coated RHEAs was researched by dynamic temperature oxidation and isothermal oxidation reflect, and the microstructure of MAO coating was investigated before and after oxidation. The results revealed that a protective oxide layer was formed to prevent the volatilization of Mo during the dynamic heating oxidation experiment, and the high temperature oxidation resistance of AlTiNbMo0.5Ta0.5Zr after MAO treatment could be significantly improved. The mass gain of MAO coated RHEAs is 8.67 mg/cm(2), which was lower than that of RHEAs without MAO coating (12.91 mg/cm(2)). (C) 2019 Elsevier B.V. All rights reserved.