Electrochemical Corrosion of Molybdenum Electrodes in an Aluminosilicate Glass Melt Containing Antimony

Abstract

The electrochemical corrosion of molybdenum electrodes in SiO 2-Al2O3-Na2O-K2O-SrO-BaO- ZrO2 glass melts both with and without antimony was investigated at 1350°C and 1450°C. The corrosion degree of the electrodes, i.e., the decrease in the diameter of the electrode, increased with increasing antimony concentration and temperature. When an alternating current (AC) of 50 Hz was applied, the corrosion degree increased with increasing current density. Any corrosion on the electrodes could not be observed up to 1 A/cm2 in the antimony-free glass melt. It was argued that the primary corrosion process is due to the oxidation of the electrodes by antimony ions in the glass melt both with and without AC supply. The AC supply accelerated the corrosion of the electrodes by the formation of molybdenum ions during anodic polarization, followed by the reduction of antimony ions rather than molybdenum ions during cathodic polarization. The increase in AC frequency, i.e., above 500 Hz, was effective in decreasing the corrosion degree of the electrodes.