EXPERIMENTAL APPLICATIONS OF SODIUM-CONTAINING ALLOYS IN MOLTEN ALKALI-HALIDES

Sodium-bismuth alloys were used as reference electrodes in contact wit h molten alkali halides to establish sodium activities. Electronic con ductivity versus sodium activity was obtained for molten sodium halide s using such alloys (similar to 5 mol% Na) in polarization experiments . Results are presented for molten NaI. Also concentration versus acti vity data for Na in Na-Bi alloys were determined as a function of comp osition (x(Na),: 0.01-0.15) and temperature (700-900 degrees C) by usi ng a simple coulometric titration technique. Sodium-lead alloys (simil ar to 8 mol% Na) were used to study the kinetics of the sodium electro de in molten NaCl using ac impedance spectroscopy combined with galvan ostatic perturbation. Results from potential measurements between alum inium and a sodium alloy electrode performed in cryolite-alumina melts to study the effects of electrolyte composition are also presented.