Effects of microstructure evolution on the oxidation behavior and high-temperature tribological properties of AlCrN/TiAlSiN multilayer coatings

AlCrN/TiAlSiN multilayer coatings have drown great attentions due to they combine both high hardness of TiAlSiN coating and outstanding oxidation resistance of AlCrN coating. In this study, AlCrN, TiAlSiN, and AlCrN/TiAlSiN multilayered coatings with two different multilayer designs: AlCrN/TiAlSiN-1 coating with fixed modulation period and ratio and AlCrN/TiAlSiN-2 coating with gradient increased AlCrN sub-layer thickness, were synthesized. The microstructure, mechanical property, thermal stability, oxidation behavior, and tribological performance of these coatings were comparably investigated. The variation of structure effects on the properties of the coatings were also discussed. The results indicated that the AlCrN/TiAlSiN multilayered coatings had superior performance than the monolayer AlCrN and TiAlSiN coatings. The AlCrN/TiAlSiN-2 coating also showed better thermal stability, oxidation resistance and high-temperature tribological properties compared to AlCrN/TiAlSiN-1 coatings, which can be attributed to the formation of a denser Al2O3 oxide layer on the surface of the coating.