Processing conditions for boron nitride coatings in fiber bundles via chemical vapor deposition

A model for the transport and reaction of BCl3 and NH3 for the deposition of BN on individual filaments in a fiber bundle at low pressures has been developed using previously published kinetic data. An operating diagram is presented which summarizes the results of the model and facilitates the choice of deposition parameters for obtaining uniform coatings throughout the bundle. The uniformity of coatings deposited on individual fibers of Nicalon, Sumitomo-Al2O3 fiber bundles, and straight weave Nicalon cloth is consistent with the model predictions