Corrosion behavior and mechanism of GH3535 alloy in NaOH, HF and H2O2 solution

Corrosion behaviors of GH3535 immersed in NaOH, HF and H2O2 solutions were investigated at RT for 600 h. The micro-morphology of surface and cross section was systematically characterized by SEM, EDS, EPMA, XRD and Nano Indenter. GH3535 showed excellent corrosion resistance in NaOH solution, but suffered serious pitting corrosion and slight grain boundary corrosion in HF solution, whereas only distinct hole corrosion in H2O2 solution due to the depletion of carbides. Element depletion, fall-off of carbides, decrease of hardness and Young's modulus of GH3535 were detected in HF and H2O2 solution. However, NaOH solution is chemically inert towards GH3535. Corrosion mechanism was also explored based on the experimental measurement and thermodynamic calculation. Results not only provide the theoretical guidance for understanding the anticorrosion mechanism of GH3535 and purifying the molten salt, also expand the application of GH3535. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

GH3535 exhibits excellent corrosion resistance in NaOH solution, but experiences serious pitting and grain boundary corrosion in HF solution, as well as distinct hole corrosion in H2O2 solution due to carbide depletion. Element depletion, carbide fall-off, and decrease in hardness and Young's modulus were observed in HF and H2O2 solutions for GH3535. NaOH solution, on the other hand, is chemically inert towards GH3535. The corrosion mechanism was explored based on experimental measurements and thermodynamic calculations, providing theoretical guidance and expanding the application of GH3535.