Abstract
High-entropy alloys (HEAs) can be deposited on substrates as thick or thin alloy films for protection against wear, corrosion, and heat, and for function enhancement and decorative purposes. In addition, various HEA nitride coatings based on HEAs can be easily deposited using reactive coating technology by allowing the atoms or ions from the targets to react with N 2 -containing Ar flow during deposition. Similarly, HEA carbides, oxides, and carbonitrides could be deposited under CH 4 -containing, O 2 -containing, and CH 4 + N 2 -containing Ar flow, respectively. Such HEA ceramic coatings also show the four core effects observed in HEAs: high-entropy, sluggish diffusion, severe lattice distortion, and cocktail effects. The structure is, in general, much simpler than expected. Amorphous, nanocrystalline, and nanocomposite films are often obtained. The properties of HEA coatings or HEA ceramic coatings can be outstanding, and these coatings have great potential for various applications if proper compositions and deposition parameters are used.