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 method of machining ceramic matrix composite components includes providing an ultrasonic vibration tool having a tool tip, and exciting the tool by providing a control current, such that the tool tip is repeatedly vibrated towards and away from a ceramic matrix composite workpiece. A slurry feed is supplied including abrasive particles to a surface to be machined by the tool tip. A vibration amplitude of the tool tip is controlled by sensing load on the tool and communicating with a computing device. The computing device controls the vibration amplitude of the tool tip. The computing device is provided with at least one memory programmed with historic data, and is operable to modify the vibration amplitude signal being sent to the tool, and comparing resulting load levels due to the change in vibration amplitude signals, and storing the change in vibration amplitude signals at the memory.

Abstract: A coated fiber structure for use in a ceramic matrix composite comprises a fiber extending along a fiber axis and an interface coating arrangement applied to and circumscribing the fiber. The interface coating arrangement comprises: a first boron nitride layer extending coaxially about and in direct contact with the fiber, a first silicon-doped boron nitride layer extending coaxially about and in direct contact with the first boron nitride layer, a carbon layer extending coaxially about and in direct contact with the first silicon-doped boron nitride layer, a second boron nitride layer extending coaxially about and in direct contact with the carbon layer, and a second silicon-doped boron nitride layer extending coaxially about and in direct contact with the second boron nitride layer. A silicon content of the first silicon-doped boron nitride layer is higher than the silicon content of the second silicon-doped boron nitride layer.

Abstract: A method of making a ceramic matrix composite component includes arranging a plurality of ceramic-based reinforcements in an array, applying an interface coating to the ceramic-based reinforcements, applying a layer of ceramic-based matrix over the interface coating, and applying a secondary interface coating such that the secondary interface coating is separate and distinct from the layer of ceramic-based matrix. A ceramic matrix composite component is also disclosed.

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.

Abstract: A coated fiber structure for use in a ceramic matrix composite comprises a fiber and a coating system applied to and circumscribing the fiber. The coating system comprises a first boron nitride layer, a silicon carbide layer extending coaxially with and in direct contact with the first boron nitride layer, a first thermally-grown oxide layer formed on the silicon carbide layer, and a second boron nitride layer extending coaxially with and in direct contact with the first thermally-grown oxide layer.

Abstract: A method of preparing a fibrous preform for use in a ceramic matrix composite comprises arranging the preform from a woven ceramic material, the preform comprising a pair of opposing outer surfaces and a midplane disposed between the pair of opposing outer surfaces, and perforating the preform with a spiked array to form a perforated preform. The perforated preform comprises a plurality of hourglass-shaped voids extending through a thickness of the preform.

Abstract: A coated fiber structure for use in a ceramic matrix composite comprises a fiber and a coating system applied to and circumscribing the fiber. The coating system comprises an interface coating layer in direct contact with the fiber, the interface coating layer comprising one of boron nitride and a boron-doped pyrocarbon, at least one intermediate layer extending coaxially with and in direct contact with the interface layer, the at least one intermediate layer comprising at least one of silicon and boron nitride, and an outer layer extending coaxially with and in direct contact with the interface layer. At least one of the interface coating layer, the at least one intermediate layer, and the outer layer comprises a metallic element.