Prepn. of boron-contg. poly:silazane, useful for prodn. of ceramics - by reacting tris-di:chloro:silyl-ethyl-borane(s) with ammonia

摘要

A process for the prodn. of boron-contg. polysilazanes of formula (II) comprises reaction of tris-silyl-borane(s) of formula B(-C2H4-SiCl2X)3 (I) with ammonia; where -C2H4- represents -CH2-CH2- or -CHMe-; X = Cl or 1-4C aliphatic residue; R is 1-4C aliphatic residue and a+b = 1. B-contg. polysilazanes of formula (II) are claimed per se. The amt. of ammonia used is sufficient to saturate all the Si-Cl gps. and bind the resulting HCl as NH4Cl and cpd. (I) is reacted as a soln. in organic solvent. The reatants are mixed at -10 to +10 deg. C and the mixt. is then heated to 10-100 deg. C. USE/ADVANTAGE - (II) are new B-contg. polysilazones, useful for the prodn. of B- and Si-contg. ceramics with excellent adhesion, hardness and surface quality, which are useful esp. for the surface coating of machine components which are subjected to mechancial and chemical stress.