Electrochemical Corrosion Performance of FeCoNiCr Medium-Entropy Alloy in Neutral, Acidic, and Saline Solutions

Hedayati, Niloofar; Heidari, Yousef; Gheisari, Khalil; Yeganeh, Mahdi

doi:10.22055/jomi.2025.49568.1029

Electrochemical Corrosion Performance of FeCoNiCr Medium-Entropy Alloy in Neutral, Acidic, and Saline Solutions

Document Type : Research Article

Authors

Niloofar Hedayati

Yousef Heidari

Khalil Gheisari

Mahdi Yeganeh

Department of Materials Science and Engineering, Faculty of Engineering, Shahid Chamran University of Ahvaz, Ahvaz, Iran

10.22055/jomi.2025.49568.1029

Abstract

This study investigates the microstructure and corrosion behavior of a vacuum arc melted FeCoNiCr medium-entropy alloy in various aqueous environments, including deionized water, 1 M sulfuric acid, and 4 wt.% sodium chloride solutions. Microstructural analysis revealed a hierarchical architecture composed of large equiaxed grains (approximately 100–400 µm) featuring a cellular substructure. Potentiodynamic polarization tests demonstrated that the alloy exhibited significantly lower corrosion resistance in the sulfuric acid environment, with a corrosion current density of 39.81 μA·cm⁻², compared to much lower values in deionized water (0.07 μA·cm⁻²) and sodium chloride solution (0.08 μA·cm⁻²). Notably, in the NaCl solution, the alloy displayed strong passivation behavior, characterized by a broad passivation range of 1146 mV and a low passive current density, closely matching its performance in deionized water. These results highlight the alloy’s excellent corrosion resistance in chloride-containing environments.

Keywords

Medium-entropy alloy

FeCoNiCr

Potentiodynamic polarization

Passivity

Sulfuric acid

Sodium chloride

Subjects