Electrochemical corrosion behavior of ferritic steels in molten (Li,Na,K)F

Abstract

The corrosion of ferritic steels in fluoride salts limits the development of advanced molten salt reactors. In-situ electrochemical measurements for B409M and B439 were performed at 700 °C in molten (Li,Na,K)F by potentiodynamic polarization and electrochemical impedance spectroscopy. The experimental results indicate that the current densities for B409M and B439 are approximately 631 and 738 μA·cm-2, respectively. The impedance spectra plots for B409M and B439 are both composed of two capacitance loops for the duration of a 100 h experimental test. Cr-depleted corrosion layers are formed on the surface of B409M and B439 through fluoridation processes. And the corrosion mechanism is also discussed.