Effects of surface-deposited WS₂ and Ag on the tribological properties and corrosion behavior of AlSn25Cu-based composite coatings

To enhance the self-lubrication and corrosion resistance of the traditional Al-Sn-Cu bearing bush coating, novel AlSn25Cu-WS₂ and AlSn25Cu-Ag composite coatings are prepared by magnetron sputtering. The introduction of WS₂ and Ag layers was found to have a significant effect on the friction and corrosion properties of the composite coatings. Scratch tests demonstrated that the AlSn25Cu-WS₂ coating suffered severe brittle delamination, while the AlSn25Cu and the AlSn25Cu-Ag coating showed plastic delamination. The friction and wear tests indicated that AlSn25Cu-Ag coatings have the best wear resistance under both dry and oil friction conditions, significantly improving the wear resistance of the AlSn25Cu coating. This can be attributed to the lubricating action of the soft Ag combined with the load-bearing capability of the AlSn25Cu layer. The AlSn25Cu-WS 2 coating indicated the lowest average friction coefficient under dry friction conditions, but failed prematurely due to interface incompatibility. However, when subjected to oil friction, it can reduce friction at a load of 2 N. Finally, the electrochemical corrosion tests showed that the AlSn25Cu-Ag coating has better corrosion resistance than the other coatings.