Effect of plasma carbonitriding on the high-temperature tribological properties of a TiAlCrN coating on 300M steel by multi-arc ion plating

A duplex treatment, namely, plasma carbonitriding followed by multi-arc ion plating, was used to improve the high-temperature tribological properties of TiAlCrN coatings on 300M steel in this research. The carbonitriding layer was first prepared on 300M steel substrates by the double glow plasma metallization technique. A corresponding heat treatment was performed, and then the TiAlCrN coating was synthesised on the surface of the carbonitriding layer and 300M steel substrates by multiarc ion plating. The microstructure, element composition and structural variations of the TiAlCrN coating were characterised using XRD, SEM and EDS. Moreover, the adhesion and high-temperature tribological behaviours of TiAlCrN coatings were studied by scratch tests and ball-on-disk wear tests, respectively. It was observed that the PCN + TiAlCrN coating showed gradient hardness support, a good chemical composition gradient and a diffusion effect in the carbonitriding process, which could significantly enhance the adhesion and tribological performance of the composite coating.