Mechanical, thermal, and high-temperature tribological properties of Ti–Al–C reinforced NiCrAlY coatings for boiler applications

Severe wear from continuous ash erosion and thermal cycling presents a critical threat to the operational safety and service life of coal-fired boilers, leading to frequent maintenance and substantial economic losses. Applying protective coatings has become a convenient and efficient strategy to improve their high-temperature wear resistance. This paper investigates the high-temperature friction and wear performance of Ti-Al-C reinforced NiCrAlY composite coatings at 600 °C, specifically for boiler applications. The coatings were prepared using plasma spraying, with Ti powder, Al powder, and graphite as raw materials. We systematically studied the effects of varying Ti-Al-C phase ratios (0∼60 wt.%) on microstructure, mechanical properties, and high-temperature tribological behavior of the coatings. The addition of Ti-Al-C to NiCrAlY resulted in a typical layered structure with a uniform and dense microstructure. Notably, the NiCrAlY coating with an optimal 20 wt.% Ti-Al-C content demonstrated superior comprehensive performance. This optimized coating exhibited a microhardness of 624.02 HV 0.2 , representing a 45.86 % increase compared to the pure NiCrAlY coating. Furthermore, it showed significantly improved high-temperature wear resistance, with its wear rate substantially decreased to 11.92×10 -15 m 3 /(N·m), (an 85.75 % decrease), and its thermal conductivity improved by 30.35 %. This study, thus, aims to provide a cost-effective strategy to extend the service life of boiler components operating under extreme thermal conditions.