HIGH-TEMPERATURE CYCLIC VOLTAMMETRY ON METAL METAL-OXIDE SYSTEMS

Cyclic voltammetry was used to obtain information on the thermodynamics of the oxidation of several metals at high temperatures (700-900-degrees-C). The electrochemical cell was composed of a yttria stabilized zirconia tablet as a solid oxygen-ion conducting electrolyte and tablets of metal/metal-oxide mixtures used as reference, working, and counterelectrodes. The peaks in the cyclic voltammograms could be attributed to oxidation and reduction reactions of the working electrode. From the potential midway between the oxidation and reduction peaks, the Gibbs reaction energy of the oxidation reactions and the oxygen equilibrium pressure could be calculated. The voltammograms show great possibilities for observing the different oxidation states of the metals.