CARBON COMPOSITE FOR THICK-WALL OBJECTS AND A METHOD FOR PREPARATION THEREOF Russian patent published in 2003 - IPC

FIELD: composite materials. SUBSTANCE: invention is designed for chemical industry and can be used when manufacturing articles operated in high-speed gas and liquid streams and chemically hostile media. For that, framework of three-dimensional structure is first formed from carbon fibers with different center-to- center distances between them. Into framework containing carbon fibers in amount 10-29% based on the volume of composite material, fine carbon filler is introduced in amount 96 to 360% of the volume of carbon fibers. Filler can be introduced either by pouring powders or by impregnation with suspensions of powders in volatile liquid under pressure and/or applying ultrasound. Framework is then saturated by pyrocarbon using thermogradient technique under excessive methane pressure 0.025-0.03 kg/sq.cm involving displacement of pyrolysis zone at velocity 0.1-0.5 mm/h over the thickness of framework at temperature in pyrolysis zone 840- 950 C. Final composite contains 24- 36 vol % of fine carbon filler and at least 19 vol % of pyrocarbon matrix, summary volume of carbon fibers and fine carbon filler constituting at least 46% and volume of pores being no higher than 19 vol %. Density of material ranges from 1.50 to 1.82 g/sq.cm. EFFECT: improved reliability of composite articles under various unfriendly conditions. 3 cl, 3 tbl