Preparation of compact and ultra-thin Si-Al-C anti-oxidation film on fibers of carbon felt

Modified sol-gel method in concocting precursory liquid of silica and alumina sol that contained egg white was adopted to immerse Polyacrylonitrile(PAN) based carbon felt, and through sintering in vacuum, the compact and ultra-thin Si-Al-C anti-oxidation film on the carbon fibers was obtained. XRD, SEM, EDAX, TEM and DSC-TGA analyses for the sintered carbon felt were carried out. The film contains both amorphous and crystal substances. Sizes of those crystals are about 50 nm-70 nm. Egg white used here acts both as excellent natural agglomerant and as active carbon source in sintering the carbides film. Beginning oxidation temperature of the coated carbon fibers in air is about 730°C, which is improved for more than 300°C as compared with that of untreated carbon fibers. This technology costs less with good results.