Microstructure and enhanced high-temperature wear performance of Al2O3 and Mo modified Stellite 12 matrix composite coating prepared by laser cladding

• A self-lubricating Stellite 12 composite coating was fabricated by laser cladding. • Effect of Al 2 O 3 and Mo on tribology of coatings was studied from RT to 1000 °C. • The wear rate of modified coating was reduced by approximately 92%. • The coordination of Al 2 O 3 and Mo was an effective strategy for Stellite 12. . To extend the service life of Stellite 12 coating as high-temperature wear resistant coating of moving parts from room temperature to 1000 °C, the Al 2 O 3 and Mo modified Stellite 12 composite coating was developed, and fabricated by laser cladding. The relationship of the strengthening phases with microhardness, microstructure and wear performance was investigated. The wear performance of coatings was evaluated from room temperature to 1000 °C via ball on disk tribo-meter against Si 3 N 4 ceramic ball. The results indicated that, compared to the Stellite 12 coating, the composite coating exhibited enhanced higher microhardness and a significant reduction in wear rate. Generally, Mo counteracted the friction-increasing effect of Al 2 O 3 within the coating, endowing the modified composite coating with self-lubricating properties. Especially, the wear rate was reduced by approximately 92% as compared with unreinforced coating from room temperature to 1000 °C. This was attributed to the dispersion strengthening and solution strengthening of strengthening phases, the in-situ formed molybdates and the refined microstructure. This research provided a strategy to reinforce the wear performance of Stellite 12 coating within a broad temperature range.