THE FORMATION AND OXIDATION OF BC3, A NEW GRAPHITE-LIKE MATERIAL

A study was performed to investigate improved oxidation resistance in a graphitic material containing high concentrations of substitutional boron. The method of producing such samples was the chemical vapor dep osition (CVD) reaction between boron trichloride and benzene at temper atures near 973 K. This reaction is known to produce a novel material containing about 25% boron, and having the chemical formula BC3. The m aterial was produced and examined for chemical composition, crystal st ructure, and microstructure. The compound BC3 has a hexagonal crystal structure similar to that of graphite. Maximum deposition rates were b etween 0.01 and 0.05 mum/day. Annealing the product of this reaction a t 1173 K for 72 hours results in a crystalline material having a layer ed structure with an interlayer spacing slightly larger than that of g raphite. Thermal analysis of the BC3 as a coating on T-300 carbon fibe rs was conducted. Thermal analysis data suggest that this novel compou nd has a much greater resistance to oxidation than T-300 carbon fibers in the temperature range 673 to 1073 K.