Study on the corrosion behavior of 316H stainless steel in molten NaCl-KCl-MgCl2 salts with and without purification

The corrosion behavior of 316H stainless steel (SS) in the impure and purified NaCl-KCl-MgCl2 salt was investigated at 700 degrees C. Results indicate that the main deleterious impurity induced corrosion in the impure salt was the absorbed moisture, present in the form of MgCl26H(2)O. 316H SS occurred severe intergranular corrosion with a corrosion depth of 130 mu m for 1000 h in the impure NaCl-KCl-MgCl2 salt. In contrast, the purification treatment of molten chloride salt by the dissolved Mg metal can remove the absorbed moisture, and the corresponding reactions were also discussed. As a result, the corrosiveness of NaCl-KCl-MgCl2 salt is reduced significantly. 316H SS occurred slight uniform corrosion with a depth of less than 5 mu m for 3000 h in the purified NaCl-KCl-MgCl2 salt.

Automated summary

This study investigates the corrosion behavior of 316H stainless steel in impure and purified NaCl-KCl-MgCl2 salt. The absorbed moisture, present as MgCl26H(2)O, is found to be the main deleterious impurity in the impure salt. Purification treatment using dissolved Mg metal effectively reduces the corrosiveness of the salt.