METHOD OF MAKING AIRTIGHT ARTICLES FROM CARBON-SILICON CARBIDE MATERIAL Russian patent published in 2015 - IPC C04B35/577 C04B35/573 B82Y30/00 

FIELD: chemistry.

SUBSTANCE: invention relates to carbon-silicon carbide composite materials, designed to operate under high thermal load and in an oxidative environment, and can be used in making space-rocket equipment, which requires air-tightness of articles under excess pressure. The method of making airtight articles from carbon-silicon carbide composite materials includes making a workpiece from porous carbonaceous material, components of which have a near linear coefficient of thermal expansion, and siliconisation of the workpiece using a vapour-liquid phase method at 1700-1850°C. Siliconisation is carried out using a workpiece made of carbon-silicon carbide composite material based on a carbon fibre frame and a carbon matrix, having density of 75-80% of the maximum possible density for said type of material, and siliconisation is carried out in two steps while alternating with feeding carbon into the pores. At the first siliconisation step, silicon is fed into the pores of the workpiece material in amount of 50-70% of the content of the carbon material in the temperature range of 1300-1500°C with temperature of silicon vapour higher than the temperature of the workpiece being siliconised, followed by heating the workpiece to 1750-1800°C and cooling at a temperature higher than the temperature of silicon vapour. After completing step 1, carbon is formed in the pores of the formed carbon-silicon carbide composite material in the form of ultra- and/or nano-dispersed particles, followed by final siliconisation, while performing initial mass-transfer of silicon into the pores of the workpiece material similar to the first step.

EFFECT: obtaining an airtight article made of carbon-silicon carbide composite material with high content of oxidation-resistant silicon carbide matrix, which is reinforced only slightly with carbonised carbon fibres.

3 cl, 1 tbl, 17 ex