High-entropy alloys (HEAs) can address the $1 trillion corrosion problem in the USA due to their ability to form stable, protective passive films. In this exploratory study, non-equimolar Ni35(TiAl)60-xFexCu5 HEAs with x = 0, 15, and 40 were synthesized and processed into powders through controlled ball-milling to serve as functional fillers in commercial epoxy-based coatings. CALPHAD-based thermodynamic phase verification and XRD analysis confirmed the presence of corrosion-resistant FCC phases in the 15% and 40% Fe-rich compositions, while EDS analysis verified compositional homogeneity. Epoxy coatings with different HEA fillers—0%, 1%, 2%, 5%, and 10% by weight—were applied on mechanically polished 1008-1010 grade low-carbon steel substrates to ensure consistent coating thickness. Electrochemical analyses evaluated the effects of coating thickness, which could mask the influence of HEA loadings. Processing, environmental, and electrochemical parameters were carefully controlled to ensure excellent repeatability. Coatings in the 30–50 µm range showed the lowest corrosion current, highest low-frequency impedance, and greatest polarization resistance, while thicker films had notably reduced barrier performance. Coatings with HEA fillers demonstrated better corrosion resistance compared to bare substrates and epoxy-only controls, with the 10% loading providing the highest polarization resistance, lowest corrosion current, and best EIS performance. This study establishes a comprehensive and reproducible materials-to-coating workflow for developing next-generation, corrosion-resistant HEA coatings suitable for marine and offshore applications.
