Redox Potential of Novel Electrochemical Buffers Useful for Corrosion Prevention in Molten Fluorides

Abstract

Cyclic voltarnmetry was used to evaluate the standard electrode potential of potential buffers such as Sm(ID/II), Yb(III/II), U(IV)/U(III),V(IIUII), and Eu(IWII) dissolved in FliNaK. (LiF-NaF-KF [46.5-11.5-42.0 mo1%]) at 610°C. These varied from -1.45V for Yb to -0.64V for Eu, respectively. The value for Sm could not be measured because the reduction potential was below that for the reduction of FLiNaK.. A reversible behavior was found for Eu and Yb, while U and V showed a more complex behavior that needs to be further evaluated. The results have shown to be invaluable in selecting a redox buffer for corrosion prevention of structural materials in contact with a molten salt at very high tem,peratures.