On the study of thermal-sprayed Ni0.2Co0.6Fe0.2CrSi0.2AlTi0.2 HEA overlay coating

The present works investigated the microstructure, mechanical properties and oxidation behavior of the Ni0.2Co0.6Fe0.2CrSi0.2AlTi0.2 high-entropy alloy (HEA) coating fabricated by atmospheric plasma spraying (APS) and high-velocity oxygen-fuel spraying (HVOF) process. The hardness of HEA coating is about 800 HV and its wear resistance (20 m/mm3) is nearly twice higher than that of the SUJ2 bearing steel (12 m/mm3). The isothermal oxidation weight gain test demonstrates that the HEA coating exhibits good oxidation resistance similar to MCrAlY coating at 1100 °C due to the formation of a protective α-Al2O3 scale. The thermal-sprayed HEA coating is thus promising as an overlay coating for high-temperature applications.