According to a method set forth herein a plurality of preform plies having first and second preform plies can be associated together to define a preform. The preform can be subject to chemical vapor infiltration (CVI) processing to define a ceramic matrix composite (CMC) structure.

The present invention relates to surface-treated prepreg composites and corresponding methods of surface treating an inorganic fabric to form a surface-treated fabric reinforced prepreg composite. The method comprises infiltrating an inorganic fabric with a first slurry mixture to form an infiltrated fabric; optionally drying the infiltrated fabric; infiltrating an inorganic paper with a second slurry mixture to form an infiltrated paper; optionally drying the infiltrated paper; and applying the infiltrated paper to at least one surface of the infiltrated fabric to form a surface-treated prepreg composite.

A coated fiber structure for use in a ceramic matrix composite includes a fiber and an interface coating system applied to the fiber. The interface coating system includes a first coating layer disposed on the fiber and a second coating layer disposed on the first coating layer. The first coating layer comprises a rare earth nitride or a rare earth carbide. The second coating layer comprises silicon-doped boron nitride.

The preparation of ceramic matrix composite (CMCs) is disclosed in which a ceramic matrix composite (CMC) preform is made with one or more integrated polymer core inserts made of a fugitive material containing polyvinyl butyral. The preform with integrated polymer core inserts to a heat treatment to remove the one or more polymer core inserts (e.g., by melting or burning). Removal of the polymer core inserts forms one or more internal cavities within the composite, which can then be subjected to densification.

A coated fiber structure for use in a ceramic matrix composite includes a fiber and an interface coating system applied to the fiber. The interface coating system includes a first coating layer disposed on the fiber and a second coating layer disposed on the first coating layer. The first coating layer comprises a rare earth nitride or a rare earth carbide. The second coating layer comprises silicon-doped boron nitride.