EIS Study of Doped High-Entropy Alloy

Abstract

The promising results obtained in the research of high-entropy alloys are increasingly encouraging new configurations of these alloys. Our research was conducted on the high-entropy CoCrFeMoNi alloy and the Ti-doped CoCrFeMoNi alloy. Electrochemical impedance spectroscopy (EIS) measurements were performed on samples with and without Ti-doped CoCrFeMoNi high-entropy alloys in order to evaluate the influence of voltage on their behavior in a simulated aggressive environment. The impedance spectra were measured between −1.0 and +0.8 V vs. SCE at various potential levels. Using an electrical equivalent circuit to match the experimental data, the impedance spectra were analyzed. The corresponding circuit that successfully fits the spectra has two time constants: the first one is for the attributes of the compact passive layer and the second one is for the features of the porous passive layer. The results show that doping CoCrFeMoNi alloy with 0.36 at.% Ti reduces the alloy’s ability to resist corrosion, as the alloy can react more quickly to the surrounding environment and cause a decrease in the corrosion resistance of the alloy.

Keywords

• high-entropy alloys
• Ti doping
• EIS
• equivalent circuit
• corrosion resistance