Abstract: A ceramic matrix composite with a ceramic matrix and a gradient layering of coating on ceramic fibers. The coating typically improves the performance of the composite in one direction while degrading it in another direction. For a SiC-SiC ceramic matrix composite, a BN coating is layered in a gradient fashion or in a step-wise fashion in different regions of the article comprising the ceramic. The BN coating thickness is applied over the ceramic fibers to produce varying desired physical properties by varying the coating thickness within differing regions of the composite, thereby tailoring the strength of the composite in the different regions. The coating may be applied as a single layer as a multi-layer coating to enhance the performance of the coating as the ceramic matrix is formed or infiltrated from precursor materials into a preform of the ceramic fibers.

Abstract: Circuits, methods, and apparatus that provide voltage references having a temperature independent output voltage that is less then the bandgap of silicon. The temperature coefficient and absolute voltage can be independently adjusted. One example generates two voltages, the first of which is proportional-to-absolute temperature and the second of which is complementary-to-absolute temperature. These voltages are placed across a first resistor. The first resistor is further connected to a second resistor to form a resistor divider. The resistor divider provides a reduced voltage that is below that bandgap of silicon. The temperature coefficient of the reference voltage provided by the resistor divider can be set by adjusting the first resistor. The absolute voltage provided can be set by adjusting the second resistor.

Abstract: Circuits, methods, and apparatus that provide voltage references having a temperature independent output voltage that is less then the bandgap of silicon. The temperature coefficient and absolute voltage can be independently adjusted. One example generates two voltages, the first of which is proportional-to-absolute temperature and the second of which is complementary-to-absolute temperature. These voltages are placed across a first resistor. The first resistor is further connected to a second resistor to form a resistor divider. The resistor divider provides a reduced voltage that is below that bandgap of silicon. The temperature coefficient of the reference voltage provided by the resistor divider can be set by adjusting the first resistor. The absolute voltage provided can be set by adjusting the second resistor.

Abstract: The present invention is ceramic matrix composite gas turbine engine component comprising a plurality of cured ceramic matrix composite plies, each ply comprising ceramic fiber tows, each ceramic fiber tow comprising a plurality of ceramic fibers, the tows in each ply lying adjacent to one another such that each ply has a unidirectional orientation. The component further comprises a layer of a coating on the ceramic fibers. The component further comprises a ceramic matrix material lying in interstitial regions between the fibers and tows of each ply and the interstitial region between the plurality of plies, wherein at least a portion of the component is no greater than about 0.021 inch thick. The present invention is also a method for making such a ceramic matrix composite component.

Abstract: An orthogonal stitch-weave method and fiber architecture. The architecture allows near-net-shape composite preforms to be fabricated, thereby reducing costs associated with complex preform shapes and increasing desired strengths of the composite.

Abstract: An inseparable assembly includes a body including a ceramic matrix composite material, and a cover including a metallic wire mesh. The cover is bonded to the body so that the cover overlaps at least a portion of the body.

Abstract: The present invention is a ceramic matrix composite turbine engine component, wherein the component has a direction of maximum tensile stress during normal engine operation. The component comprises a plurality of biased ceramic plies, wherein each biased ply comprises ceramic fiber tows, the tows being woven in a first warp direction and a second weft direction, the second weft direction lying at a preselected angular orientation with respect to the first warp direction, wherein a greater number of tows are woven in the first warp direction than in the second weft direction, and wherein a number of tows in the second weft direction allows the biased plies to maintain their structural integrity when handled.

Abstract: The present invention is a hybrid ceramic matrix composite turbine engine component comprising an outer shell section(s) and an inner core section(s), wherein the outer shell section(s) and the inner core section(s) were bonded together using an MI process. The outer shell section(s) comprises a SiC/SiC material that has been manufactured using a process selected from the group consisting of a slurry cast MI process and a prepreg MI process. The inner core section(s) comprises a material selected from the group consisting an Si/SiC composite material and a monolithic ceramic material. The Si/SiC composite material may be manufactured using the Silcomp process. The present invention may be a high pressure turbine blade, a high pressure turbine vane, a low pressure turbine blade, or a low pressure turbine vane. The present invention is also a method of manufacturing a hybrid ceramic matrix composite turbine engine component.

Abstract: A method of manufacturing a turbine engine component comprising the steps of providing and laying up a plurality of ceramic plies comprising woven ceramic fiber tows to form a turbine engine component shape, inserting a plurality of tows of oxidizable fugitive fibers into the component shape, such that each fugitive fiber tow passes through a preselected number of ceramic plies, burning off the fugitive fiber tows, the burning producing through-thickness void regions, rigidizing the component shape with a layer of BN and a layer of SiC to form a coated component preform using chemical vapor infiltration, and partially densifying the coated component preform using carbon-containing slurry and filling the through thickness void regions, and further densifying the coated component preform with at least silicon to form a ceramic matrix composite turbine engine component with in-situ ceramic matrix plugs formed where the through-thickness void regions were located.

Abstract: A method of manufacturing a turbine engine component is disclosed. The method includes the steps of providing a plurality of ceramic cloth plies, each ply having woven ceramic fiber tows and at least one fugitive fiber tow, laying up the plurality of plies in a preselected arrangement to form a turbine engine component shape, oxidizing the fugitive fibers to produce fugitive fiber void regions in the ply, rigidizing the component shape to form a coated component preform using chemical vapor infiltration, partially densifying the coated component preform using carbon-containing slurry, and further densifying the coated component preform with at least silicon to form a ceramic matrix composite turbine engine component having matrix rich regions.

Abstract: A ceramic matrix composite with a ceramic matrix and a gradient layering of coating on ceramic fibers. The coating typically improves the performance of the composite in one direction while degrading it in another direction. For a SiC-SiC ceramic matrix composite, a BN coating is layered in a gradient fashion or in a step-wise fashion in different regions of the article comprising the ceramic. The BN coating thickness is applied over the ceramic fibers to produce varying desired physical properties by varying the coating thickness within differing regions of the composite, thereby tailoring the strength of the composite in the different regions. The coating may be applied as a single layer as a multi-layer coating to enhance the performance of the coating as the ceramic matrix is formed or infiltrated from precursor materials into a preform of the ceramic fibers.

Abstract: The integral layer provides a ductile interface for attachment locations of a turbine engine component where a metallic surface is adjacent the attachment location. The ductile layer provides a favorable load distribution through the composite at the attachment location, and eliminates the need for a metallic shim.

Abstract: The present invention is a ceramic matrix composite turbine engine component, wherein the component has a region of expected higher interlaminate stress during normal engine operation. The component includes both coated fiber tows and uncoated fiber tows arranged together into a preselected form, wherein the uncoated fiber tows are located at predetermined regions of expected high interlaminate stress. The invention further includes method of manufacturing a CMC such as a composite turbine engine component, wherein the component has a region of expected higher interlaminate stress during engine operation.

Abstract: An orthogonal stitch-weave method and fiber architecture. The architecture allows near-net-shape composite preforms to be fabricated, thereby reducing costs associated with complex preform shapes and increasing desired strengths of the composite.

Abstract: A bond coat composition is provided for applying to the surface of a ceramic composite component between the composite substrate and the thermal barrier coat. The composition includes an alumina powder, a silica-yielding liquid, glass frits, and sufficient solvent to permit mixing of the components and forming a bond coat.

Abstract: The present invention is a ceramic matrix composite turbine engine component, wherein the component has a direction of maximum tensile stress during normal engine operation. The component comprises a plurality of biased ceramic plies, wherein each biased ply comprises ceramic fiber tows, the tows being woven in a first warp direction and a second weft direction, the second weft direction lying at a preselected angular orientation with respect to the first warp direction, wherein a greater number of tows are woven in the first warp direction than in the second weft direction, and wherein a number of tows in the second weft direction allows the biased plies to maintain their structural integrity when handled.

Abstract: A ceramic matrix composite laminate includes at least two directional, continuous ceramic fiber preform lamina each being formed of interwoven or braided fibers. A layer of non-woven mat includes a plurality of chopped ceramic fibers mixed with a bonding agent. The non-woven mat layer is interposed between adjacent directional, continuous ceramic fiber preform lamina to substantially eliminate inter-laminar gaps formed between the adjacent directional, continuous ceramic fiber preform lamina. The additional chopped fiber content improves the interlaminar mechanical and thermo-mechanical material properties of resulting ceramic matrix composite laminate.

Abstract: The present invention is a hybrid ceramic matrix composite turbine engine component comprising an outer shell section(s) and an inner core section(s), wherein the outer shell section(s) and the inner core section(s) were bonded together using an MI process. The outer shell section(s) comprises a SiC/SiC material that has been manufactured using a process selected from the group consisting of a slurry cast MI process and a prepreg MI process. The inner core section(s) comprises a material selected from the group consisting an Si/SiC composite material and a monolithic ceramic material. The Si/SiC composite material may be manufactured using the Silcomp process. The present invention may be a high pressure turbine blade, a high pressure turbine vane, a low pressure turbine blade, or a low pressure turbine vane. The present invention is also a method of manufacturing a hybrid ceramic matrix composite turbine engine component.

Abstract: An inseparable assembly includes a body having a first surface and a second surface. The body includes an oxide-based ceramic matrix composite material having a first predetermined ductility. The assembly further includes a crack extending through the body between the first surface and the second surface, and a patch bonded to at least one of the first surface and the second surface overlapping at least a portion of an edge of the crack. The patch includes a second material having a second predetermined ductility that is greater than the first ductility.

Abstract: An inseparable assembly includes a body including a ceramic matrix composite material, and a cover including a metallic wire mesh. The cover is bonded to the body so that the cover overlaps at least a portion of the body.