METHOD OF PROCESSING ARTICLES OF SILICON CARBIDE AND/OR CARBON-BASED CERAMIC MATERIALS Russian patent published in 2006 - IPC C04B41/84 

FIELD: ceramics.

SUBSTANCE: invention relates to technology of producing articles from structural materials based on silicon carbide and/or carbon, e.g., from caked carbon carbide, and can be utilized to manufacture articles operated under high thermocyclic loading conditions at temperatures up to 1650-1750°C in air and in fuel combustion products as well as in heat-insulation elements. Invention consists in formation of Si₃N₄ and SiO₂ layers in ceramics surface in order to improve heat resistance of ceramics, resistance to high-temperature oxidation, and high-temperature mechanical properties. Formation of said Si₃N₄ and SiO₂ layers also leads to reduced thermal expansion factor compared to materials not processed according to the method proposed. Method consists in impregnation of silicon carbide and/or carbon-based articles with organosilicon compounds followed by heat treatment under a nitrogen atmosphere and protection against oxidation achieved by additional impregnation with organosilicon compounds followed by two-step heat treatment in air: first at 700-800°C with ageing for 1.5-2.5 h and then at 1250-1350°C with ageing for 0.25-1 h. As organosilicon compound, ethyl silicate can be utilized. It would be appreciated when temperature of heat treatment under a nitrogen atmosphere is selected within a range of 1350-1450°C.

EFFECT: increased permissible operation temperature for articles manufactured according to invention.

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