The paper concerns composite materi

The paper concerns composite materials made of silicone rubber matrix and ceramic fillers used as flame resistant coverings for electrical cables. Under fire, such materials must be able to form, relatively quickly, compact and stiff protecting coating, strong enough to maintain integrity of electrical circuit, even up to melting temperature of metal core. The residue of fired silicone rubber or silica filled elastomer exhibit a form of white powder. There is no evidence of solidification of silica particles, even after heating at 1100°C. However, the addition of some ceramic phases results in reaction with silica matrix (starting at about 900°C) producing a liquid phase, what facilitates particle binding. At lower firing temperatures (600°C) the problem of binding between the product of pyrolysis (silica) and filler is also present, what results in formation of fragile surface shield.The problem can be overcome by the addition of certain inorganic materials to the silicone rubber matrix. The paper discusses their influence on ability of silicone rubber composites, additionally containing glassy phase, wollastonite, mica, aluminium hydroxide, montmorillonite or calcined caoline, to ceramization.