Microstructure and wear-resistance of AlCoCrFeNi based composite coatings strengthened with ceramic particles: A review

High-entropy alloys (HEAs), exemplified by the AlCoCrFeNi system, have garnered significant interest in materials science owing to their superior mechanical properties, including exceptional strength and hardness, characteristics that render them particularly well suited for wear-resistant applications. Recent developments have demonstrated that the incorporation of ceramic reinforcement phases into AlCoCrFeNi-based matrices represents an effective strategy for enhancing tribological performance via composite coating architectures. This review offers a comprehensive examination of coating systems, including reinforcement phase selection criteria and matrix functionality. A systematic analysis of matrix-strengthening approaches is provided, elucidating fundamental mechanisms and detailing how variations in alloying elements drive microstructural evolution and consequent improvements in wear resistance. Particular attention is devoted to interfacial optimization, offering a detailed discussion of interface characteristics and optimization strategies achieved through adjustments in elemental composition. Finally, the present limitations of AlCoCrFeNi composite coatings are reviewed, and prospective research avenues are suggested.