Abstract
Porous carbon materials have been sealed perfectly with a molten silicate glass, where the wettability of the carbon to the molten glass was improved by infiltration and pyrolysis of perhydropolysilazane. The interfacial structure between the carbon and glass depended on the N2 partial pressure during sealing. Cristobalite was produced at the interface under lower N2 partial pressures. Transformation of cristobalite during cooling after sealing led to formation of many cracks at the interface. Therefore, the transformation is though to decrease adhesion of the glass layer to the carbon substrate. Coating of the glass at higher N2 partial pressures did not followed by the cristobalite production. The structural changes occurring as a result of variation in N2 partial pressures related to thermodynamic calculations. The coating remarkably improved the oxidation resistance of the carbon.
