Abstract: A fixture for processing a ceramic matrix composite article includes first and second tool segments that each have an exterior side and an interior side. The interior side has a border mate face, and the interior side of the first tool segment faces the interior side of the second tool segment such that the border mate faces align and circumscribe a working region for holding a fiber preform that is to be coated with a ceramic material. The tool segments each having an array of through-holes that open to the working region to permit inflow of gaseous precursor into the working region. A seal circumscribes the working region and blocks a gap between the border mate faces to limit inflow of the gaseous precursor through the gap into the working region.

Abstract: A coated fiber structure for use in a ceramic matrix composite comprises a fiber and an interface coating arrangement applied to and circumscribing the fiber. The interface coating arrangement comprises a first boron nitride layer, a silicon carbide layer extending coaxially with and in direct contact with the first boron nitride layer, and a second boron nitride layer on a side of the silicon carbide layer opposite the first boron nitride layer. The thickness of the silicon carbide layer ranges from 100 nm to 500 nm, and an RMS roughness of the silicon carbide layer is less than 20 nm.