Industrial experience with a cathodic electrochemical method to reduce the molybdenum electrode corrosion

Abstract

In an industrial all-electric glass tank a cathodic dc voltage was superimposed on the ac heating voltage at two molybdenum electrodes for about 8 months to reduce the corrosion through the formation of a protective layer. One starting electrode could be used as counter electrode for the cathodic protection of the molybdenum heating electrodes. A platinum electrode was installed as reference electrode to carry out electrochemical measurements (impedance measurements, current-potential curves). After an 8 months' running time a reduction of molybdenum corrosion of about 25 % could be proved due to the cathodic protection in comparison with unprotected heating electrodes. The results of the electro chemical investigations on the industrial glass tank showed to a certain extent deviations from the former laboratory tests.