Molten-aluminum corrosion resistance and wear behavior of CrAlN-based coatings

Aluminum die-casting molds operate under severe molten-aluminum corrosion and cyclic friction conditions, requiring advanced surface coatings to extend service life. CrAlN, CrAlYN, and CrAlMoN coatings were deposited by arc ion plating, and the effects of Y and Mo alloying on molten-aluminum corrosion and post-corrosion tribological performance were systematically investigated. A correlation between corrosion resistance and post- corrosion wear behavior was established. CrAlYN maintains superior structural integrity after 6 h of molten-aluminum exposure, exhibits better resistance to molten-aluminum corrosion than CrAlN, and retains the most stable tribological performance. Y alloying promotes grain refinement and grain-boundary stabilization, facilitating the formation of a dense Cr 2 O 3 /Y-Al-O composite oxide layer that suppresses Fe-Al interdiffusion and enhances mechanical stability during sliding. CrAlMoN shows a reduced friction coefficient due to lubricious MoO 3 ; however, its wear resistance is lower than CrAlYN because brittle Mo 2 N phases compromise oxide film stability, leading to localized spallation. These results demonstrate that Y alloying is more effective than Mo in improving the molten-aluminum corrosion-wear resistance of CrAlN-based coatings, providing mechanistic insight for durable coating design in aluminum die-casting applications.