Electrochemical Surface Modification of Al<sub>8</sub>Co<sub>19</sub>Cr<sub>23</sub>Fe<sub>32</sub>Ni<sub>18</sub> in H<sub>2</sub>SO<sub>4</sub>: A High-Entropy Alloy with High Pitting Corrosion Resistance and High Oxidation Resistance
Li Pao, Masashi Nishimoto, Izumi Muto, Yu Sugawara
Abstract
An Al8Co19Cr23Fe32Ni18 high-entropy alloy with a solid solution of Al was prepared, and its pitting corrosion resistance in 0.1 M NaCl and high-temperature oxidation resistance at 1273 K were assessed. The pitting potential of this alloy is lower than that of the Al-free Co19Cr23Fe40Ni18 alloy, although its oxidation resistance is higher. The decrease in the pitting potential owing to Al addition was attributed to Al in the surface oxide film and Al nitride inclusions in the metal matrix. For the Al8Co19Cr23Fe32Ni18 alloy, potentiodynamic polarization in 1 M H2SO4 improved the pitting corrosion resistance without decreasing the high-temperature oxidation resistance.
Topics & Concepts
Materials scienceAlloyPitting corrosionCorrosionMetallurgyOxideElectrochemistryMetalNitridePolarization (electrochemistry)Nuclear chemistryElectrodeChemistryComposite materialLayer (electronics)Physical chemistryHigh Entropy Alloys StudiesHigh-Temperature Coating BehaviorsChalcogenide Semiconductor Thin Films