Preparation and Properties of (MgCoNiCuZn)O High Entropy Oxide Ceramic Coating

High entropy oxide (MgCoNiCuZn)O ceramic powders were prepared by high temperature solid state reaction sintering at different temperatures (700-1 000 ℃). The ceramic coating was prepared on the surface of Inconel 718 alloy substrate by atmospheric plasma spraying technique, and the microstructure and properties of ceramic coatings were studied. The results show that (MgCoNiCuZn)O high entropy oxide ceramic powders with a single rock salt phase structure were synthesized at sintering temperatures of 900, 1 000 ℃. The ceramic coatings prepared with the ceraimic powders sintered at the two temperatures had hardness of 5.42-5.94 GPa and bonding strength of 45.4-48.5 MPa. The bonding strength and hardness of the ceramic coating prepared with powders sintered at 1 000 ℃ were relatively high. The friction coefficient of ceramic coating abrasing against alumina balls was 0.59-0.69, and the wear rate was 2.59×10^-5-4.13×10^-5 mm³·N^-1·m^-1; the main wear mechanism was abrasive wear and fatigue spalling. The friction coefficient and wear rate of the ceramic coating prepared with powders sintered at 1 000 ℃ were relatively low, and the worn surface had thin and shallow ploughing and small and few spalling pits.