Corrosion Behavior of the Electrochemical Couple: Hastelloy/Carbon Material in Zirconium Fluoride - Sodium Fluoride Melts

Time dependencies for the parameters (current, voltage, inner resistance) of short-circuited galvanic cell: Hastelloy-carbon material have been studied in NaF-ZrF4 eutectic melt at 600- 650oC. Analysis of these data, together with the data on polarization of separate electrodes at open circuit conditions, showed that short-circuit current is related to the rate of corrosion of the alloy contacted with carbon. In the presence of zirconium, the short-circuit current corresponds to the rate of zirconium interaction with the fluoride melt and can be used for studies of its dissolution kinetics. It was found that contact of Hastelloy with carbon material results in an increase of corrosion rate both in pure NaF-ZrF4 eutectic melt and with the additives of LaF3. The presence of zirconium in fluoride melt suppresses the corrosion process.