METHOD OF SURFACE AND VOLUME PROTECTION OF CERAMIC MATRIX C/SiC AND SiC/SiC-TYPE COMPOSITES Russian patent published in 2008 - IPC C04B41/87 

FIELD: composite materials.

SUBSTANCE: invention relates to technology of applying coatings to provide surface and volume protection of ceramic matrix C/SiC and SiC/SiC-type composites against oxidation at elevated operation temperatures of articles. Method comprises saturation of composite material with oxides of refractory group IV elements (Ti, Zr, Hf, Th, U), drying, and subsequent treatment of composite with aqueous or organic solutions or sols of group III metals followed by heat treatment. Refractory group IV oxides and actinide oxides are deposited onto composite from 30-50 wt % water-organic suspension of fractioned nanocrystalline micropowders having spherical particle size 0.8-1.5 μm and composed of nanoparticles 20-150 nm in size. Drying is performed at 150-300°C. Aqueous and organic solutions and sols are prepared from group III metal (Al, Sc, Y, all lanthanides) salts or complex compounds. Final heat treatment is performed at 900-1000°C, after which protective glassy layer is deposited.

EFFECT: achieved surface and volume protection of composite against high-temperature oxidation, enabled preparation of high-temperature crystalline phases at low synthesis temperatures, and enabled modifying coating composition in deposition step.

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