Microstructure formation, corrosion properties, and tribological properties of laser-cladded CrCoNi medium-entropy alloy coatings

In this study, near-fully dense CrCoNi medium-entropy alloy coatings were deposited on an AISI 1045 steel substrate via laser cladding. Afterwards, we investigated the microstructure formation, corrosion properties, and tribological properties. Microstructural observations revealed that the CrCoNi coating has a single-phase face-centered-cubic structure and exhibits columnar grains. Furthermore, cellular substructures and elemental segregation were achieved and discussed. Potentiodynamic polarization tests in 0.1 mol/L HCl solution revealed that as compared with the AISI 1045 steel substrate, the CrCoNi coating exhibits enhanced corrosion resistance owing to a multi-stage potentiodynamic polarization behavior. Also, the dry sliding tribological tests revealed that the CrCoNi coating exhibits enhanced tribological properties due to the ultrafine microstructures and high hardness.