Branched polycarbosilanes and their use in the production of silicon carbide

Claim 1

A process for producing silicon carbide which comprises pyrolyzing in an inert atmosphere a branched polycarbosilane which has been produced by reacting, with an active metal in an inert solvent at an elevated temperature, a compound system having at least two different monomers of the formula (I) (CH.sub.2 ═CH).sub.a R.sub.b SiX.sub.c (CH.sub.2 X)d (I) wherein R is lower alkyl, X is halo, a is 0 or 1, b is 0-3, c is 0-4, d is 0-4, a+b+c+d totals 4, a+d totals at least 1, and where at least said one said monomers is characterized by a+c+d totals 3 or 4, said compound system being selected such that its average molar functionality is at least 2.3, a plurality of silyl units are branching sites in the polymer backbone, and the formation of silicon-carbon bonds is favored, said branched polycarbosilane comprising more than one unit of the formula ##STR5## where R is a lower alkyl, a is 0 or 1, b is 0-3, C is 0.14 4, d is 0-4 and a+b+c+d totals 4, with the provisos that, in different units, a, b, c, d and R may differ, but that, in at least one unit, a+d must total 1 or more and, in at least 1 unit, a+c+d must total 3 or more.