Corrosion Properties of Cr(27)Fe(24)Co(18)Ni(26)Nb(5) Alloy in 1 N Sulfuric Acid and 1 N Hydrochloric Acid Solutions

The composition of the Cr(27)Fe(24)Co(18)Ni(26)Nb(5) high-entropy alloy was selected from the FCC phase in a CrFeCoNiNb alloy. The alloy was melted in an argon atmosphere arc-furnace, followed by annealing in an air furnace. The dendrites of the alloy were in the FCC phase, and the eutectic interdendrites of the alloy comprised HCP and FCC phases. The microstructures and hardness of this alloy were examined; the results indicated that this alloy was very stable. This microstructure and hardness of the alloy almost remained the same after annealing at 1000 °C for 24 h. The polarization behaviors of Cr(27)Fe(24)Co(18)Ni(26)Nb(5) alloy in 1 N sulfuric acid and 1 N hydrochloric acid solutions were measured. Both the corrosion potential and the corrosion current density of the Cr(27)Fe(24)Co(18)Ni(26)Nb(5) alloy increased with increasing test temperatures. The activation energies of the Cr(27)Fe(24)Co(18)Ni(26)Nb(5) alloy in these two solutions were also calculated.