Effect of Mo Content on the Microstructure, Tribological Properties, and Corrosion Behavior of FeCoCrNiMo x High‐Entropy Alloy Coatings

To enhance the surface properties of H13 steel, FeCoCrNiMo x ( x = 0.3, 0.6, 0.9) high‐entropy alloy (HEA) coatings are fabricated on an H13 substrate via laser cladding. This study systematically investigates the influence of Mo content on the coating's microstructure, hardness, and electrochemical behavior of the coating at room temperature. All coatings exhibit a single face‐centered cubic structure, with Mo incorporation inducing lattice distortion. The microstructure is significantly regulated by the Mo content. When x = 0.3, the HEA coating exhibits optimal performance, with a microhardness of 437.85 HV 0.2 , approximately twice that of the substrate. However, a significant decrease in hardness is observed when x ≥ 0.6. In a 5% NaCl solution, all coatings exhibit superior corrosion resistance compared to the substrate, with the resistance initially increasing and then decreasing as the Mo content rose. These findings provide critical insights for developing high‐performance surface coatings for hot‐work molds.