INSULATING COATING FOR CERAMIC FIBROUS MATERIAL AND COATING PROCEDURE METHOD Russian patent published in 2001 - IPC

FIELD: inorganic coatings. SUBSTANCE: ceramic fibers designed for fiber-reinforced ceramic composites are coated by boron nitride with amorphous structure having general formula BSi_xN_1+1,33x with 2 to 42 wt % of silicon, which is completely in bound state. Coating is characterized by coefficient of thermal expansion from 0.25 to 0.35% at heating to 1500 C, which imparts low adhesiveness with regard to fibrous material. Coating is applied on the latter by placing it into reactor furnace operated at uniformly distributed temperature from 1300 to 1750 C, into which gaseous nitrogen, boron, and silicon sources, in particular boron trichloride as boron source and trichlorosilane as silicon source, are introduced. Low adhesiveness allows coating to be easily detached from ceramic material. EFFECT: prevented high-temperature (up to 1500 C) oxidation and hydrolysis. 9 cl, 1 dwg, 4 tbl, 5 ex