There exist large potential differences among pure Ni, Fe and Cr
in molten (Li,Na,K)F at 700 8C, with the largest value observed
between Ni and Cr. Dramatic galvanic corrosion occurs, with a
galvanic corrosion effect of 55.94 for the couple Ni/Fe, 70.65 for the
couple Fe/Cr and 80.97 for the couple Ni/Cr. Cr for the couples Ni/Cr
and Fe/Cr, and Fe for the couple Ni/Fe are the anode during the
galvanic corrosion process, and their dissolution is accelerated
greatly. Small amounts of anodic metals-containing products were
formed on the surface of cathodic metals after galvanic corrosion
measurements, probably due to the fact that the dissolved Cr or Fe
ions can diffuse toward the cathode to be reduced partly. This
deposition reaction may reduce the potential difference between
two metals, and thus weaken the galvanic process to a certain
extent. However, the galvanic corrosion process can also be
facilitated by the dissolved Cr or Fe ions which could be
multivalent (Cr2+/Cr3+, Fe2+/Fe3+) and be involved in the oxidation