High-temperature wear behaviour of AlCoCrFeNiTi0.5 coatings produced by HVOF

The multi-principal material concept of high-entropy alloys (HEA) is receiving increasing attention as a new approach for surface engineering. Especially their high-temperature wear resistance offers various application possibilities. In this study, the wear behaviour of AlCoCrFeNiTi0.5 HEA coatings is investigated at elevated temperatures. High-velocity-oxygen-fuel thermal spraying of inert gas atomised feedstock enables a dense coating structure and low oxidation. Microstructural analyses reveal the formation of body centred cubic phases with B2 and A2 structure for the powder and the coating. The wear resistance of the coatings was investigated in a wide temperature range under atmospheric conditions in reciprocating wear test. A strong dependence of the wear behaviour on the test temperature has been observed. With increasing temperature, the wear resistance increases due to the formation of a protective oxide film. The high wear resistance under harsh environmental conditions makes AlCoCrFeNiTi0.5 a conceivable option for the application of HEA coatings.