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This work aimed to explore the effect of cBN (cubic boron nitride) content on the microstructures and wear-corrosion resistance of the CoCrFeNiTi0.8-xcBN (x = 0, 2, 4, 6 wt.%) particle-reinforced high-entropy alloy coatings. Laser cladding technology was used to prepare the coatings on TC18 substrate. The microstructures, volume wear rates and polarization curves were characterized. The results showed that the CoCrFeNiTi0.8-xcBN coatings had an optimal forming quality under the process parameters: laser power of 1500 W, scanning rate of 12 mm/s and overlapping rate of 60%. As the cBN content increased, plenty of TiN and TiB2 hard particles formed in situ in the coatings, significantly improved the wear resistance. As a result, the volume wear rate of CoCrFeNiTi0.8-6cBN was only 4.0% and 16.5% of that of TC18 substrate and CoCrFeNiTi0.8 coating, respectively; the wear mechanism changed from adhesive wear + oxidative wear to abrasive wear + oxidative wear gradually. Moreover, CoCrFeNiTi0.8-xcBN coatings can effectively inhibit the infiltration of corrosive media by dense organizational characteristics and the physical barrier effect of oxidation-protective films. After 480 h of neutral salt spray (NSS) test, the CoCrFeNiTi0.8-xcBN coatings exhibited excellent corrosion resistance, both of the appearance and protection rating reached level 10. Therefore, it can be used as the wear-corrosion-resistant coating for the TC18 substrate in a NSS environment. [ABSTRACT FROM AUTHOR]

Hard films play essential roles in the wear protection of metal moving components. In this study, the TiCN/Cr 3 C 2 -NiCr and TiCN/WC-CoCr duplex coatings were designed and fabricated by utilizing the high-velocity oxygen fuel and the high-temperature chemical vapor deposition processes. The effects of two cermet interlayers on the microstructure, mechanical characteristics, stress distribution, and sliding wear behavior of the top TiCN films were thoroughly explored. Results evidenced that the TiCN/WC-CoCr duplex coating had a smoother surface than the TiCN/Cr 3 C 2 -NiCr duplex coating. The load-bearing capacity and fracture toughness of TiCN/WC-CoCr duplex coating were superior to TiCN/Cr 3 C 2 -NiCr duplex coating due to WC-CoCr coating possessing higher hardness, elastic modulus and high-temperature stability. The TiCN/WC-CoCr duplex coating also exhibited lower Von Mises stress compared to TiCN/Cr 3 C 2 -NiCr duplex coating, and the stress concentration zone was further away from the interface between the TiCN film and the cermet interlayer. The wear resistance of TiCN/WC-CoCr duplex coating was approximately 2 and 1.5 times that of the single TiCN film and TiCN/Cr 3 C 2 -NiCr duplex coating under 20 N load. Moreover, the wear mechanisms of the duplex coatings involved abrasive wear, adhesive wear and oxidative wear. This work significantly enhanced the wear resistance of TiCN films, which will broaden the application of TiCN film in non-load-bearing metal moving components. • The Cr 3 C 2 -NiCr and WC-CoCr interlayers were able to modify the nucleation and growth mechanisms of the top TiCN film. • The TiCN/WC-CoCr duplex coating had stronger wear resistance than the single TiCN film and TiCN/Cr 3 C 2 -NiCr duplex coating. • The wear mechanisms of the single TiCN film and duplex coatings involved abrasive wear, adhesive wear and oxidative wear. [ABSTRACT FROM AUTHOR]