Abstract This investigation studies the microstructures of FeCoNi and CrFeCoNi alloys, and their polarization behaviors in 1 M deaerated H2SO4 and NaCl solutions. The results revealed that both FeCoNi and CrFeCoNi… Click to show full abstract
Abstract This investigation studies the microstructures of FeCoNi and CrFeCoNi alloys, and their polarization behaviors in 1 M deaerated H2SO4 and NaCl solutions. The results revealed that both FeCoNi and CrFeCoNi alloys had an FCC granular structure, and their lattice constants were approximately 0.357 nm in as-cast and as-annealed states. However, many HCP precipitates were observed in the matrix of CrFeCoNi alloy in both as-cast and as-annealed states. The corrosion resistance of FeCoNi alloy in 1 M H2SO4 solution was better than that of CrFeCoNi alloy. The corrosion resistances of both FeCoNi and CrFeCoNi alloys in 1 M H2SO4 solution were better than that of 304 stainless steel. The corrosion resistance of FeCoNi alloy in 1 M NaCl solution was better than that of CrFeCoNi alloy. The activation energies of FeCoNi and CrFeCoNi alloys were calculated using the Arrhenius equation; in 1 M H2SO4 solution, they were 28.5 and 20.8 kJ/mol, respectively; and in 1 M NaCl solution, they were 24.6 and 89.1 kJ/mol, respectively.
               
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