Vinay, B.U.Arya, S.B.2026-02-082025High-Entropy Alloy Coatings: Fundamentals and Applications, 2025, Vol., , p. 344-35297810329075059781040447413https://doi.org/10.1016/j.jcsr.2025.110128https://idr.nitk.ac.in/handle/123456789/33488High-entropy alloy (HEA) coatings have emerged as a potential solution for addressing the combined effects of mechanical wear and electrochemical degradation that lead to aggravated material failure. Currently used coatings, such as hard ceramic coatings (TiN, CrN, DLC) and thermal spray coatings (WC-Co and NiCrAlY), have problems including instable passive film formation, brittleness, and selective element leaching, which limits their effectiveness in harsh tribo-corrosion environments. HEA coatings can overcome these limitations by leveraging factors, such as multi-element synergy, sluggish diffusion, severe lattice distortion, and self-healing passive films, thereby enabling superior hardness, wear resistance, and corrosion stability. These coatings are particularly suitable for marine propellers, drilling tools, biomedical implants, and aerospace bearings, where frictional wear and corrosive attack occur simultaneously. This chapter explores tribo-corrosion mechanisms in HEA coatings, covering topics such as passive film breakdown, wear-assisted electrochemical reactions, and synergistic degradation effects. Additionally, the chapter discusses advanced fabrication techniques, including laser cladding, thermal spraying, and electrochemical deposition, which enhance tribo-corrosion resistance. Furthermore, this work provides a comparative analysis on subjects, including conventional coatings, experimental findings, and emerging advancements in nanostructured, self-healing, and functionally graded HEA coatings. Finally, future research directions are provided that highlight machine learning-assisted alloy design, in-situ wear-corrosion monitoring, and sustainable HEA formulations, which are expected to advance industrial adoption and long-term durability. © 2026 Taylor & Francis Group, LLC.