Preparation and Oxidation Resistance of the Borate Glass Coating on Graphite Anode

The protection coating, which was used on graphite anode, was developed. The materials were SiO2, B2O3 and soluble glass as binder. The micrographic pattern, the phase composition and the components of borate glass coating were analyzed. The results indicated that the coating was morphology of borate glass at 700~850°C, the components were SiO2, and B2O3 from XRD analysis, the coating could permeate into the pores of the graphite anode and seal the cracks developed by the coating, and it was adhesive strongly to the graphite anode from SEM analysis. The effects of the temperature and time on oxidation weight loss ratio and oxidation rate of graphite anode coating were observed and analyzed. The mechanism of oxidation resistance of the coating layer was explained. In addition, the thermal cycle experiments with the borate glass coating were done at 800°C and 850°C, and the results demonstrated the sample had good ability of resistance to thermal shock.