Continuous chemical coating of substrate with boron nitride, especially fiber used in fiber-reinforced composite, uses organic boron compound and large excess of ammonia at high temperature

摘要

Continuous chemical coating of substrate with boron nitride (BN) from the gas phase comprises reacting an organic boron compound with an at least 40-fold molar excess of ammonia, with respect to the borane, at a temperature = 1000 deg C. Independent claims are also included for the following: (a) BN-coated substrates produced in this way; (b) BN-coated substrates in which the BN layer has a hydrolysis resistance = 40 mg m-2, determined by boiling under reflux in distilled water for 60 minutes and determining the amount of hydrolyzable BN from the ammonium and borate ion concentrations, measured photometrically using Nesslers reagent and Azomethin H respectively.