Degradation of insulating materials including SiO2 due to SF6 gas dissociation products

Materials including silicon dioxide (SiO₂) are degraded by SF₆ gas dissociation products. In Toshiba Laboratory changes in surface resistivity and volume resistivity of insulating materials including SiO₂, for instance porcelain, due to SF₆ dissociation products were investigated. It was found that surface resistance and volume resistance of these materials decreased with the existence of SF₆ gas dissociation products and moisture. And it was found too that chemical products that lessened the surface and volume resistivity is some acids and some salts of these acids. By chemical analysis almost of these acids are assumed to be H₂SiF₆.