Patent ID: 7510742
Filing Date: 2009-03-31
Classification: C04B,C23C,Y10T

Abstract:
1. A method for forming a coating comprising the steps of: providing a reaction chamber having a first tube having a first inlet and a second tube having a second inlet; placing a substrate in the reaction chamber; said substrate placing step comprises placing a substrate made of at least one fabric ply having SiC fibers woven into each said ply in the reaction chamber; heating the substrate to a deposition temperature; forming at least one coating layer on said substrate; and said forming step comprising introducing ammonia into said reaction chamber through said second tube and introducing nitrogen into said reaction chamber through said first tube, introducing a boron halogen precursor into said reaction chamber via said first tube to form a boron nitride layer, stopping the flow of said boron halogen precursor, and introducing a silicon halogen precursor into said reaction chamber through said first tube to form a silicon nitride layer, said forming step further comprising pumping the reaction chamber with ammonia and nitrogen after the flow of said boron halogen precursor has stopped and before the flow of said silicon halogen precursor begins; wherein said step of introducing said ammonia into said reaction chamber through said second tube prevents said boron halogen precursor and said silicon halogen precursor from reacting with said ammonia prematurely.