Boron carbide fibres films, coatings etc - by heating mixts of boron-hydrogen cpds with organic polymers

摘要

Prods of boron carbide, or mixts with carbon, are made by processing into required form a soln. or melt of a boron-hydrogen cpd. (A) and an organic polymer, (B) which thermally decomposes to give carbon, opt. with addition of co-agents, (C) and subsequently heating to 800 degrees -2350 degrees C. (A) is pref. a boranate esp. diammonium- deca- or dodecaboranates, or their alkyl-, aryl- and allyl-ammonium cpds. (B) is pref. a cpd. contg. no oxygen, esp. polyacrylonitirle or its copolymers, (C) is pref. polyethylene oxide, polypropylene oxide, polyacrylamide, acrylamide-acrylic acid co-polymers, polyisobutylene, PMMA, polyisoprene a polystyrene, in a conc. of 0.01-2 wt.%. The mixts. can be spun dry or in soln into continuous fibres, which are converted into boron carbides at lower temps. than those based on boron-oxygen cpds. and polymers. The products are more oxidation resistant than carbon fibres.