Electrospark‐Deposited AlCrFeCoNi High‐Entropy Alloy Coatings on Steel: Microstructure Evolution, Mechanical Properties, and Corrosion Response

Recent advancements in high entropy alloys have garnered considerable attention due to their exceptional properties, especially for applications in extreme environments, where coating materials are critical to performance and cost‐effectiveness. This study investigates the microstructure, mechanical properties, and corrosion behavior of AlCrFeCoNi high entropy alloys (HEA) coatings deposited on medium carbon steel using electrospark deposition. The as‐deposited coatings exhibit a body‐centered cubic phase with cellular grains and a uniform elemental distribution. Postdeposition heat treatment induces elemental diffusion, leading to phase segregation, elemental clustering, and a noticeable reduction in microhardness from 730 to 540 HV, and yield strength from 1036 to 761 MPa. Both as‐deposited and heat‐treated coatings demonstrate enhanced corrosion resistance, with the latter showing corrosion rates in both NaCl solution of 5.31 μA cm −2 lower, and acidic environments of 6.17 μA cm −2 lower. These findings highlight the potential of AlCrFeCoNi HEA coatings for extending the service life of components operating under harsh conditions.