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The AlCrN and AlCrON coatings were deposited on plasma nitrided H13 steels through ion-source-enhanced arc ion plating, and their structures, mechanical properties, thermal stabilities, and tribological properties were investigated. Structural analysis showed that the monolayer AlCrN and AlCrON bilayered coatings were mainly composed of fcc-AlCrN and fcc-AlCrON solid solution phases respectively. Upon the addition of thin AlCrON layer, the hardness of AlCrN/AlCrON coating slightly decreased from about 30.5 GPa to 28.6 GPa, and the thermal stability was improved after annealing at 700 °C. Both coatings exhibited excellent wear resistance at room temperature, while all wear process involved a combination of wear mechanisms, including severe abrasion and oxidation at an evaluated temperature. The AlCrON bilayered coating showed better wear resistance than that of AlCrN coating due to a dense anti-oxidation layer and better adhesion at a high temperature, making it suitable for die tool protection coatings.

AlCrN/AlCrMoN multilayer coatings with various bilayer numbers (1, 2, 4, and 6) were deposited on high speed steel (HSS) via arc ion plating technology. The effects of bilayer numbers on the microstructure, mechanical and tribological properties were investigated. XRD and TEM results showed that the solid solution (Al, Cr, Mo) N was the main phase in the AlCrN/AlCrMoN multilayer coatings. As compared with the AlCrN/AlCrMoN-1 coating, the AlCrN/AlCrMoN multilayer coatings showed the improved adhesion, hardness and tribology performance. The AlCrN/AlCrMoN-4 coating showed the highest adhesion (Lc2 = 52 N) and micro-hardness (3500 HK 0.05 ). The AlCrN/AlCrMoN-4 coating also exhibited the lowest friction coefficient and wear rate both at room temperature and high temperature due to the optimal structure and good overall performance.