# US 12,759,271 B2 · Ceramic matrix composites and method of making > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,759,271 B2 - Document ID: US12759271B2 - Status: Granted - Kind: B2 - Application number: 18/571,459 - Filed: 2022-06-17 - Published: 2024-08-22 - Granted: 2026-10-13 - Earliest claimed: 2021-06-18 - Assignees: Rtx Corporation - Applicants: Raytheon Technologies Corporation - Inventors: James T. Roach; Brendan Michael Lenz; Kathryn Sarah Read - Web page: https://patentgrep.com/patent/US12759271B2 ## CPC - B32B 18/00: Layered products essentially comprising ceramics, e.g. refractory products - B32B 3/26: characterised by a particular shape of the outline of the cross-section of a continuous layer; characterised by a layer with cavities or internal voids {(foam layer B32B5/18; layer of synthetic resin characterised by fillers that create voids or cavities B32B27/205); characterised by an apertured layer} - B32B 5/12: characterised by the relative arrangement of fibres or filaments of {different layers, e.g. the fibres or filaments being parallel or perpendicular to each other} - B32B 5/26: another layer {next to it} also being fibrous or filamentary {(relative arrangement of fibres or filaments of different layers B32B5/12)} - B32B 38/08: Impregnating - B32B 2250/20: All layers being fibrous or filamentary - B32B 2260/023: Two or more layers - B32B 2262/105: Ceramic fibres - B32B 2262/106: Carbon fibres, e.g. graphite fibres - B32B: LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM ## Abstract A ceramic matrix composite laminate comprises a ceramic matrix that encapsulates a plurality of layers. Each layer comprises fibers. Each layer comprises a plurality of fill fibers and a plurality of warp fibers or a plurality of bias fibers. The outermost layer contains a different concentration of fibers per unit volume than a layer located near an interior of the ceramic matrix composite laminate. A gradient in the number of fibers exists between the outermost layer and the layer located at the interior of the ceramic matrix composite laminate, or a combination thereof. A combined ceramic matrix composite comprises a plurality of composite laminates; wherein each laminate has a different fiber concentration gradient from another laminate that it is in contact with. ## Claims ### Claim 1 A ceramic matrix combined composite laminate comprising: a plurality of composite laminates; wherein each laminate has a different fiber concentration gradient from another laminate that it is in contact with; and wherein each laminate comprises: a ceramic matrix that encapsulates a plurality of layers that comprise fibers; wherein each layer comprises a plurality of fill fibers and a plurality of warp fibers; wherein each laminate comprises a first layer, a second layer and a third layer, wherein the first layer is an outermost layer of the laminate, the second layer is in an interior of the laminate closer to a center of the laminate than the first layer, and the third layer is in the interior of the laminate closer to the center of the laminate than the second layer, wherein a spacing between weft fibers of the first layer is greater than the spacing between weft fibers of the second layer and the spacing between warp fibers of the first layer is the same as the spacing between warp fibers of the second layer, and wherein a spacing between weft fibers of the second layer is greater than the spacing between weft fibers of the third layer and the spacing between warp fibers of the second layer is the same as the spacing between warp fibers of third layer. ### Claim 2 (depends on 1) The ceramic matrix combined composite laminate of claim 1, wherein the fibers are ceramic fibers, carbon fibers, or a combination thereof. ### Claim 3 (depends on 1) The ceramic matrix combined composite laminate of claim 1, wherein the combined composite laminate is a deltoid-shaped preform. ### Claim 4 (depends on 1) The ceramic matrix combined composite laminate of claim 1, wherein an areal space between fill and warp fibers decreases from the outermost layer of each laminate to the layer located in the interior of the laminate. ### Claim 5 (depends on 1) The ceramic matrix combined composite laminate of claim 1, wherein the fiber concentration gradient is a linear gradient. ### Claim 6 (depends on 1) The ceramic matrix combined composite laminate of claim 1, wherein the fiber concentration gradient is a curvilinear gradient. ### Claim 7 (depends on 6) The ceramic matrix combined composite laminate of claim 6, wherein the curvilinear gradient follows a spline function having exponents between 2 and 5. ### Claim 8 (depends on 1) The ceramic matrix combined composite laminate of claim 1, wherein the combined composite laminate comprises n separate laminates, where n is an integer. ### Claim 9 (depends on 1) The ceramic matrix combined composite laminate of claim 1, wherein a distance between fill fibers gradually decreases from the outermost layer of each laminate to the layer located in the interior of the laminate, while a distance between warp fibers remains constant from the outermost layer to the layer located in the interior of each laminate. ### Claim 10 (depends on 1) The ceramic matrix combined composite laminate of claim 1, wherein the ceramic matrix comprises SiC, Al2O3, BN, B4C, Si3N4, MoSi2, SiO2, SiOC, SiNC, and/or SiONC. ### Claim 11 (depends on 1) The ceramic matrix combined composite laminate of claim 1, wherein the fibers comprise SiC. ### Claim 12 (depends on 1) The ceramic matrix combined composite laminate of claim 1, wherein a matrix density at the outermost layer of each laminate is the same as that in the interior of each laminate. ### Claim 13 (depends on 1) The ceramic matrix combined composite laminate of claim 1, wherein the matrix is substantially devoid of pores in the interior of each laminate. ### Claim 14 (depends on 1) The ceramic matrix combined composite of claim 1, wherein a phase difference between peaks of warp fibers in successive layers is reduced with each layer from the outer surface to the center of the ceramic matrix. ### Claim 15 (depends on 14) The ceramic matrix combined composite of claim 14, wherein the phase difference between a first layer that is an outermost layer and a second layer is between 30 and 60 degrees, the phase difference between a second layer and a third layer is 25 to 45 degrees and the phase difference between the third layer and a fourth layer is 20 to 30 degrees. ### Claim 16 A method for manufacturing a ceramic matrix composite comprising: placing in an infiltration chamber a laminate comprising: a plurality of layers that comprise fibers; wherein each layer comprises a plurality of fill fibers and a plurality of warp fibers; wherein the plurality of layers includes a first layer, a second layer and a third, wherein the first layer is an outermost layer of the laminate, the second layer is in an interior of the laminate closer to a center of the laminate than the first layer, and the third layer is in the interior of the laminate closer to the center of the laminate than the second layer, wherein a spacing between weft fibers of the first layer is greater than the spacing between weft fibers of the second layer and the spacing between warp fibers of the first layer is the same as the spacing between warp fibers of the second layer, and wherein a spacing between weft fibers of the second layer is greater than the spacing between weft fibers of the third layer and the spacing between warp fibers of the second layer is the same as the spacing between warp fibers of third layer; infiltrating the plurality of layers with a precursor that comprises a ceramic precursor; and joining a plurality of laminates such that a fiber concentration gradient per unit volume in each laminate is different from that of another laminate in the plurality of laminates. ### Claim 17 (depends on 16) The method of claim 16, wherein a matrix density at the outermost layer of each laminate is the same as that in the interior of the laminate. ### Claim 18 (depends on 16) The method of claim 16, wherein an areal space between fill and warp fibers gradually decreases from the outermost layer of each laminate to the layer located in the interior of the laminate. ### Claim 19 (depends on 16) The method of claim 16, wherein the fibers comprise SiC and wherein the ceramic matrix comprises SiC, Al2O3, BN, B4C, Si3N4, MoSi2, SiO2, SiOC, SiNC, and/or SiONC. ### Claim 20 (depends on 16) The method of claim 16, wherein a distance between fill fibers gradually decreases from the outermost layer of each laminate to the layer located in the interior of the laminate, while a distance between warp fibers remains constant from the outermost layer to the layer located in the interior of the laminate or wherein a distance between warp fibers gradually decreases from the outermost layer of each laminate to the layer located in the interior of the laminate, while a distance between fill fibers remains constant from the outermost layer to the layer located in the interior of the laminate.