Corrosion behavior of CuCrFeNiMn high entropy alloy system in 1 M sulfuric acid solution

Abstract

The high pressure torsion (HPT) process was used to process the FeNiCoMoV high-entropy alloy. The open-circuit potential test, the potentiostatic polarization curve test and the electrochemical impedance spectroscopy were used to study the effect of corrosion behavior of FeNiCoMoV High Entropy Alloy in 1M NaOH Solution. The results show that the grain refinement of FeNiCoMoV alloy is significant after 6 cycles of high pressure torsion, the phase structure has not changed and the electrochemical impedance of HPT has a significant increase in 1M NaOH solution. The potential is 11.97% higher than the initial state, the corrosion current density is 93.77% lower than the initial state, and the corrosion resistance is improved obviously.

Corrosion of high entropy alloys

“…Several researchers have explored the influence the effect of copper (Cu) on the corrosion and electrochemical response of CCAs. [58][59][60] Hsu et al 58 investigated the corrosion behaviour of the FeCoNiCrCu x system (with x taken as 0, 0.5 and 1) in 0.6 M NaCl and observed that increasing Cu content resulted in a higher i corr , lower E corr and lower E pit values for this system (Fig. 8c).…”

“…The effect of Cu on the corrosion of the CuCrFeNiMn system was also investigated by Ren et al 59 using immersion tests and potentiodynamic polarisation tests in 1 M H 2 SO 4 . The CuCr 2 Fe 2 -Ni 2 Mn 2 alloy with a low Cu content and minimal elemental segregation had the highest corrosion resistance, whereas the Cu 2 CrFe 2 Ni 2 Mn 2 alloy with the higher Cu content and more substantial elemental segregation had the poorest corrosion resistance.…”

“…59 However, no elaboration on the nature of the phase (s) present at the grain boundaries-which preferentially corroded -was provided. It was proposed that the addition of Cu favours elemental segregation, thus increasing the corrosion rate of Curich CCAs.…”

Corrosion-Resistant High-Entropy Alloys: A Review

“…Signs of corrosion can be observed in the Al-Ni-rich BCC phase, according to the surface morphology of the alloys after the immersion tests. Ren et al studied the influence of the Cu addition on the corrosion behavior of the CoCrFeNiCux alloy in the 1 M H2SO4 [48]. Similar to the case in the NaCl solution, due to the segregation of Cu, the interaction between the Cu-rich, Cr-depleted inter-dendrite and the Cr-rich, Cu-depleted dendrite led to galvanic corrosion.…”

“…The addition of Mo improved the corrosion resistance in the NaCl solution (as mentioned above) but impacted the corrosion behavior in the H2SO4 solution. The reason is that according to the Pourbaix diagram [49], the formation of the protective molybdenum species on the surface is impossible when considering the 0.5 M H2SO4 acid Ren et al studied the influence of the Cu addition on the corrosion behavior of the CoCrFeNiCu x alloy in the 1 M H 2 SO 4 [48]. Similar to the case in the NaCl solution, due to the segregation of Cu, the interaction between the Cu-rich, Cr-depleted inter-dendrite and the Cr-rich, Cu-depleted dendrite led to galvanic corrosion.…”