Preparation of FeCoNiCrMn High Entropy Alloy by Electrochemical Reduction of Solid Oxides in Molten Salt and Its Corrosion Behavior in Aqueous Solution

Abstract

For the first time, powdery FeCoNiCrMn high entropy alloy (HEA) with homogeneous grain size was prepared by one-step electrolysis of solid oxides in molten CaCl2 at 850°C. The HEA with FCC structure and uniform distribution of components was formed during the electrochemical reduction of the oxides, no melting step was needed. In addition, a certain amount of carbon was introduced to the alloy during the electrolysis in a form of chromium carbide due to the dissolution of the carbon anode. The HEA powders were then made into a bulk material and its corrosion behaviors in different aqueous solution were investigated by polarization curve tests. The HEA exhibits a very low corrosion rate, 0.778 μA cm−2 in 1M KOH, 0.879 μA cm−2 in 3.5 wt% NaCl, 32.9 μA cm−2 in 1M HCl solution, respectively. The robust precursors and relatively simple process suggest an economical and environmentally friendly method for preparing HEA powders.