Microstructures and Properties of FeCoNiCr High-Entropy Alloy Coatings Prepared by Electrodeposition

Abstract

High-entropy alloys (HEAs) have attracted increasing attention owing to their multicomponent characteristics with notable high-entropy effects. However, obtaining HEAs with improved properties is still challenging. The properties of HEAs can be modulated by the fabrication technique. Electrodeposition could achieve the desired performance characteristics of HEA coatings while operating at reduced processing temperatures and energy consumption levels. Herein, novel FeCoNiCr HEA coatings were electrodeposited on copper substrates under various current densities. The microstructure, coating thickness, hardness, wear resistance, and corrosion properties of the FeCoNiCr HEA coatings prepared at different current densities were all examined. X-ray diffraction revealed HEA coatings with a single disordered face-centered cubic solid solution phase. Scanning electron microscopy indicated uniform and dense surfaces of FeCoNiCr HEA coatings fabricated under a current density of 25 A/dm2, with significantly reduced coating cracking and improved structural integrity. The coatings prepared at 25 A/dm2 also exhibited maximum thickness and favorable bonding with the substrate, as well as notably enhanced wear resistance. As the preparation current density increases, the hardness of the coating increases. The hardness of the coating reaches its maximum at 30 A/dm2. FeCoNiCr HEA coatings fabricated under a current density of 25 A/dm2 in a 3.5 wt% NaCl solution simulated seawater conditions demonstrated improved electrochemical resistance to corrosion. By comparing the microstructure, elemental content, and properties of coatings prepared at various current densities, it was found that the FeCoNiCr HEA coating prepared at 25 A/dm2 showed the best performance.