Corrosion Performance of Sn-Doped AlCrFeNiMn High-Entropy Alloy Synthesized via Arc-Melting Technique

Abstract Failure of materials such as steels during engineering applications can result in economic harm; hence, developing new corrosion-resistant materials is critical. In this work, high-grade powders of Al, Cr, Fe, Mn, and Ni were used to synthesize an equimolar AlCrFeNiMn high-entropy alloy (HEA) for potential chemical industry application. The cast alloy's properties were further altered by the addition of 1at%, 3at%, and 5at% tin (Sn) as alloying additives. To assess the impact of Sn on the alloy's resistance to corrosion, potentiodynamic polarization tests were conducted in various acidic and basic environments. Several surface inspection techniques, including scanning electron microscopy (SEM), optical microscopy (OPM), X-ray diffractrometry (XRD), and energy-dispersive X-ray spectroscopy (EDS), were employed to examine the morphological changes and elemental composition of the alloy after it was subjected to corrosive conditions. The nano-indentation machine was used to analyze the materials' nanohardness. TGA analysis was also performed to determine how Sn additions affected the AlCrFeNiMn HEA’s thermal stability. In 0.5 M HCl solution, the Sn-doped alloys demonstrated good corrosion resistance. Their exposure to 0.5 mol/L H 2 SO 4 solution, on the other hand, found to be deleterious to their electrochemical stability. The weight loss of 5 at% Sn-doped samples in 0.5 M H 2 SO 4 solution was found to be substantially reduced. The mass of all the samples stayed constant in 3.5 wt% NaOH solution.