Abstract: Methods of making ceramic matrix prepregs are described. The methods include exposing a coated tow of ceramic fibers to a ceramic matrix slurry comprising a solvent and ceramic precursor. The coating is at least partially removed and the slurry infuses into the ceramic fibers to form prepreg. Steps to form ceramic matrix composites are also described, including forming the prepreg into a green body, and sintering the ceramic precursor.

Abstract: Methods of making ceramic matrix prepregs are described. The methods include exposing a coated tow of ceramic fibers to a ceramic matrix slurry comprising a solvent and ceramic precursor. The coating is at least partially removed and the slurry infuses into the ceramic fibers to form prepreg. Steps to form ceramic matrix composites are also described, including forming the prepreg into a green body, and sintering the ceramic precursor.

Abstract: A fibrous substrate having a first coefficient of thermal expansion and having porous characteristics is formed from discrete elements, such as carbon fibers, having anisotropic properties. A matrix formed from a refractory material encases the discrete elements and has a second coefficient of thermal expansion different from the first coefficient. The matrix has minimal chemical or mechanical bonding to the discrete elements to provide for a displacement of the matrix relative to the substrate with mechanical shock or changes in temperature. The matrix includes a first element having refractory properties and selected from the group consisting of hafnium, zirconium, tantalum, tungsten and molybdenum and also includes a second element bound to the first element. The matrix is preferably formed by providing a mixture of a first gas containing the refractory element and a second gas containing the second element and by introducing the gases into a chamber containing the substrate.

Abstract: A porous substrate is formed from discrete elements preferably anisotropic and permeable to oxygen and preferably having a first coefficient of thermal expansion. A pyrolytic material permeable to oxygen may be deposited in a thin layer on the discrete elements. A barrier material (e.g. boron carbide or silicon carbide) may be deposited in a thin layer on the pyrolytic material to inhibit diffusion of elements into the pyrolytic material. A material impermeable to oxygen (e.g. boron nitride or silicon nitride) may be deposited in a thin layer on the barrier material. A refractory matrix permeable to oxygen may be deposited on the impermeable material. The matrix may include a metallic element (e.g. silicon, hafnium, tantalum or zirconium) and another element (e.g. oxygen, nitrogen, carbon or boron) chemically bonded to the metallic element. The matrix may have a second coefficient of thermal expansion different from the first coefficient and may have a minimal bond to the substrate.