Electrochemical Preparation of Fe0.5CoNiCuSnx Medium Entropy Alloys and Their Corrosion Properties

Abstract

The exploration of efficient preparation methods and corrosion-resistant medium entropy alloys (MEAs) has attracted significant attentions in recent years. In this paper, powdery Fe0.5CoNiCuSnx (x = 0, 0.05, 0.08, and 0.1) MEAs were prepared by the one-step electrochemical reduction of metal oxides in molten Na2CO3-K2CO3 using a Ni11Fe10Cu oxygen-evolution inert anode. The effects of Sn on the structures, morphologies, and corrosion behaviors of the prepared MEAs were systematically investigated. The electrolytic MEAs exhibited a single face-centered cubic phase at x≤0.05, and the CuSn-rich phase would be segregated in the alloys at 0.08 ≤ x ≤ 0.1. Moreover, increasing Sn reduced the particles size of MEAs, and Sn improved the corrosion resistance of MEAs in 0.5 M H2SO4, 1 M KOH, and 3.5% NaCl solutions. The electrolytic MEA(Sn0.05) exhibited the best corrosion resistance, which had the corrosion current densities of 3.7 × 10−5 A cm−2 (0.5 M H2SO4), 1.2 × 10−5 A cm−2 (1 M KOH), and 1.6 × 10−5 A cm−2 (3.5 wt% NaCl) at room temperature. Overall, this paper not only provides a green approach to preparing Sn-containing MEAs, but also offers an efficient way to control structures and morphologies, thereby improving the corrosion resistance.