Mechanical, oxidation, and cutting properties of AlCrN/AlTiSiN nano-multilayer coatings

The design of multilayered structure is a promising way to tailor the microstructure and properties of the hard coatings. In this study, AlCrN, AlTiSiN and nano-multilayer AlCrN/AlTiSiN coatings were deposited and their microstructure, mechanical, oxidation and cutting properties were comparatively investigated. The results showed that the AlCrN/AlTiSiN coating, possessing two phase and denser microstructure, showed improved hardness (39.4 GPa) and adhesion strength, as compared with the AlCrN and AlTiSiN coatings. The AlCrN/AlTiSiN coating also exhibited excellent oxidation resistance up to 1000 °C and its oxidation scale was composed of a thin and dense Al-rich oxide, due to the multilayer structure acted as an effective barrier to block elemental diffusion to retard the oxidation process. In the turning tests for SKD11, the AlCrN/AlTiSiN coating demonstrated good tool life (~800 m), which should be attributed to its higher hardness, good adhesion strength and oxidation resistance, as compared with the monolithic AlCrN and AlTiSiN coatings.