Development of Large Diameter Carbon Monofilament.
Contract rept. Jun 72-Jan 73,
UNITED AIRCRAFT RESEARCH LABS EAST HARTFORD CT
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The purpose of this work was to develop a process for preparing large-diameter carbon monofilament. The process selected involved chemical vapor deposition using boron trichloride, methane and hydrogen gases and a conventional boron type reaction in which the substrate is resistively heated. Amorphous carbon-boron alloys were formed when gas mixtures containing greater than 20 percent methane 80 percent BCl3 were used. The strongest carbon-boron monofilament was achieved using a CH4BCl3 gas ratio of 0.44. This gas ratio produced a monofilament in which the average composition of the deposit was 75 wo boron and 25 wo carbon. When this high an amount of boron is attained, it is suspected that the deposit reacts more readily with the impurities present on the surface of the carbon substrate. The carbon-substrate fiber was precleaned in chlorine and used as a substrate. With the precleaned substrate, the strength of the carbon-boron alloy monofilament was considerably improved. The experimentation showed that high strength, high modulus carbon-boron alloy monofilament can be produced from a BCl3, CH4, and H2 gas system. The modulus of the monofilament appears to be linearly dependent upon the percent of boron in the monofilament. jg p6
- Inorganic Chemistry
- Physical Chemistry
- Properties of Metals and Alloys