Corrosion of molybdenum electrodes was investigated in alkali-alkaline earth-silica glass melts containing antimony oxide. Corrosion was performed under ac and superimposed dc conditions as protection in cathodic or anodic mode. The extent of corrosion was assessed by SEMIEDX and by ICP analysis of residual glass. Under simple ac conditions the molybdenum electrodes exhibited severe corrosion, namely active diffusion of Mo into the glass. But there was no evidence for the formation of an alloy between molybdenum and antimony. Under anodic protection the corrosion seems to decrease to some extent by formation of a molybdenum oxide layer on the surface. Under cathodic protection, the amount of molybdenum ions diffused into the glass melts was reduced to one fourth of that diffusing under anodic protection and the surface state of electrodes was very clean. However the formation of protective layers was not found. The results showed that the cathodic protection is the most effective method to reduce the corrosion of molybdenum electrodes in alkali-alkaline earth-silica glass melts doped with antimony.
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