High-entropy ceramic coatings

High-entropy ceramics are the novel ceramic materials containing no less than four different cations or anions in a single phase. Due to the superior properties of hardness and strength, corrosion and high-temperature oxidation resistance, thermal conductivity and stability, biocompatibility, and so forth, they have rapidly attracted extensive attention for the development of next-generation coating materials. This chapter intends to provide a general up-to-date overview of four typical high-entropy alloy ceramic coatings (nitrides, oxides, carbides, and borides), including their development history, fabrication principles and methods, specific composition, structures, and application potential. Emphasis is placed on deciphering how the high-entropy-induced disordered structure contributes to the unexpected properties and utilizing these attractive properties for future applications.