Effects of chloride ions on electrochemical reaction of 316 stainless steel in mixtures of molten nitrate salts. Issue 8 (18th August 2020) - Zhu, M.
Abstract: Effects of chloride ion on decomposition of ternary nitrate and corrosion behaviors of 316 stainless steel (316 SS) were studied by electrochemical corrosion tests in molten salt. Chemical composition and morphology of the corrosion products were analyzed using x‐ray diffraction and scanning electron microscopy equipped with energy disperse spectroscopy. Composition analysis for molten salt combined with morphology analyses of corrosion layer showed that presence of chlorine ions slowed down decomposition of ternary nitrate and increased corrosion rate of stainless steel markedly. The polarization curve obtained indicated that the corrosion current density increased from 3.02 mA ⋅ cm −2 to 8.76 mA ⋅ cm −2 with the addition of 10 % NaCl. Electrochemical impedance spectroscopy indicated a decrease in charge‐transfer resistance of the double layer between 316 SS and ternary Nitrate containing 10 % NaCl, resulting in a decreased corrosion resistance of 316 SS. Abstract : Corrosion behaviors of 316 stainless steel in HITEC molten salt with and without Cl − at 450 °C are studied by electrochemical methods. Addition of Cl − increases the corrosion current density and decreases the transfer resistance of 316 stainless steel. However, presence of Cl − slowed down the decomposition of HITEC salt.