... purity 4.Surface chemical 5.hydrophobic Sealed fumed silica Sealed fumed silica has size small, super specific surface area, ... , thickening sex, thixotropy, electrical insulation, etc. Sealed fumed silica is mainly used for Silicone Rubber ,Adhesives, Sealants,Coatings, ... is generallyregarded as unique in industry because of its unusual particle characteristics. white carbon black SiO2 silica sand