Investigating corrosion behavior of Ni and Ni-20Cr in molten ZnCl2

Corrosion of Ni and Ni-20Cr in molten ZnCl2 under argon atmosphere at 593 K was investigated using cyclic polarization in combination with various electron microscopy techniques. Cyclic polarization measurements yielded significantly lower corrosion rates for pure Ni than for Ni-20Cr. Corrosion of the Ni-20Cr alloy is attributed to selective anodic dissolution of Cr, which forms a chromium chloride film at the metal-salt interface. The corrosion in Ni and Ni-20Cr is accelerated by grain boundary attack through intergranular corrosion, followed by the formation of pore-salt network regions. The related corrosion mechanisms and dissolution kinetics are discussed.

Automated summary

The corrosion of Ni and Ni-20Cr in molten ZnCl2 at 593 K under argon atmosphere was investigated using cyclic polarization and electron microscopy techniques. It was found that the corrosion rates for Ni-20Cr were significantly higher than for pure Ni, attributed to selective anodic dissolution of Cr. The mechanisms of corrosion and dissolution kinetics were discussed, with grain boundary attack and formation of pore-salt network regions identified as acceleration factors.