Microstructure and wear properties of TiN-Al2O3-Cr2B multiphase ceramics in-situ reinforced CoCrFeMnNi high-entropy alloy coating

In order to improve the hardness and wear resistance of high entropy alloy (HEA) coating, the TiN-Al2O3-Cr2B multiphase ceramics reinforced CoCrFeMnNi high-entropy alloy coating was prepared by the plasma cladding. The composite coating was composed of face-centered-cubic (FCC) structure alloy phase and the in-situ synthesized TiN-Al2O3-Cr2B multiphase ceramics, and exhibited the good bonding in interface. Compared with the pure CoCrFeMnNi coating, the hardness of the composite coating (320 HV0.3) increased by 71.90%, owing to the dispersion distribution of TiN-Al2O3-Cr2B multiphase ceramics and the solid solution of Al/Ti in the HEA matrix. The wear rate of reinforced HEA composite coating were 0.51 x 10(-5), 0.98 x 10(-5), 0.30 x 10(-5) and 0.25 x 10(-5) mm(3) N-1 m(-1), which were 20.48% (25 degrees C), 34.75% (200 degrees C), 16.13% (400 degrees C) and 10.12% (600 degrees C) of pure HEA coating, respectively. The wear mechanisms of the cladded coatings were adhesive wear, abrasive wear, oxidation wear. The strengthening of TiN-Al2O3-Cr2B multiphase ceramics acted as a disincentive to the adhesive wear of the composite coating during high temperature sliding progress. Besides, the multiphase ceramics played the load-bearing and load transfer role to improve the wear resistance of the composite coating.