Corrosion Behavior of High-Entropy AlNiCoCuZr Equiatomic Alloy in an NaCl Solution

Abstract—The functional characteristics of high-entropy alloys, in particular, their corrosion properties, are the subject of active study by many scientific groups. The interest in high–entropy alloys is due to their relative ease of production (most often by electric arc melting at low cooling rates), corrosion resistance, and high values of mechanical properties (hardness, strength). A special place among high-entropy alloys is occupied by compositions based on aluminum and transition metals (nickel, iron, cobalt) due to their functional characteristics commensurate with some bulk amorphous compositions. Information on the features of corrosion processes in them is required for a wider industrial application of such alloys. In this work, the corrosion behavior of Al₂₀Ni₂₀Co₂₀Cu₂₀Zr₂₀ alloy is studied in an aqueous 5 wt % NaCl solution at a temperature of 25°C during 1500 h. The alloy is found to be subjected to minimum corrosion due to the dissolution of nickel and cobalt at a corrosion rate of 2.98 ± 0.01 mg/(m² h). Electrochemical measurements demonstrate that the corrosion potential is –0.19 V relative to the Ag/AgCl reference electrode, and polarization into the anode region leads to selective dissolution of nickel and cobalt.