COMPOSITE MATERIAL (VARIANTS) AND METHOD OR PREPARING THEREOF, METHOD OF TREATING FIBROUS SEMI-FINISHED PRODUCT (VARIANTS) Russian patent published in 2001 - IPC

FIELD: preparation of ceramic composite materials. SUBSTANCE: described are composite materials (variants), method of preparing thereof and method of treating fibrous semifinished product. Composite material includes fibrous semi-finished product comprising non oxide ceramic fiber having at least one coating comprising element selected from group formed by carbon, nitrogen, aluminium and titanium, and matrix silicon-based alloy which contains carbon dissolved therein. Described in other embodiment is composite material made of silicon carbide reinforced by silicon carbide fiber which has heat conduction of at least about 9.5 W/h m K at 2200 F, ultimate rupture strength of at least 20 ksi: at 2200 F as determined by ASTM C 1275-94. Method comprises using fibrous semi-finished product with fibers comprising silicon carbide, infiltrating fibrous semi-finished product with suspension containing from 97 to 99.0 wt.% of silicon and from 0.1 to 3 wt.% of added carbon, and impregnating semi- finished product with melted silicon-containing alloy at temperatures from 1410 to 1450 C. Claimed method comprises using semi-finished product which has from 20 to 80 vol % of coated fiber, said fiber containing from 20 to 80 vol % of porosity, adding suspension which contains ceramic particles into pores of said semi-finished product to form semi-finished product with porosity which is less than original porosity of fibrous semi-finished product and applying ceramic particles onto external surface of semi-finished product to form monolithic layer thereof on surface of semi-finished product. Described in other embodiments is method which comprises using fibrous semi-finished product comprising silicon carbide, impregnating semi-finished product with suspension which comprises diffractive mixture of silicon carbide particle, and infiltrating semi-finished with matrix alloy comprising silicon, and also method comprising use of fibrous semi-finished product comprising nonoxide ceramic fiber having at least one coating, said coating containing element selected from group formed by carbon, nitrogen, aluminium and titanium, fiber having destruction temperature ranging from 1410 to 1450, impregnating said semi-finished product with suspension containing silicon carbide particles and from 0.1 to 3 wt.% of carbon, preparing coating mixture which comprises alloy containing impregnating metallic material and said element which is present in composition, and polymer, applying coating mixture onto at least one of sections of surface impregnated in stage for preparing semi-finished product, heating coating mixture to temperature within 1410 to 1450 C to melt alloy and infiltrating fibrous semi-finished product with melted alloy for period from 15 to 240 min to prepare ceramic fiber reinforced ceramic composite material. Said inventions make it possible to prepare constructional ceramic materials having high aerodynamic and physico-chemical characteristics. EFFECT: improved properties of the composite material. 30 cl, 3 ex, 8 dwg, 1 tbl