A method of manufacturing a coated reinforcing fiber for use in Ceramic Matrix Composites, the method comprising pre-oxidizing a plurality of silicon-based fibers selected from the group consisting of silicon carbide (SiC) fibers, silicon nitride (Si.sub.3N.sub.4) fibers, SiCO fibers, SiCN fibers, SiCNO fibers, and SiBCN fibers at between 700 to 1300 degrees Celsius in an oxidizing atmosphere to form a silica surface layer on the plurality of silicon-based fibers, forming a plurality of pre-oxidized fibers; applying a rare earth orthophosphate (REPO.sub.4) coating to the plurality of pre-oxidized fibers; and heating the plurality of REPO.sub.4 coated pre-oxidized fibers at about 1000-1500 degrees Celsius in an inert atmosphere to react the REPO.sub.4 with the silica surface layer to form a rare earth silicate or disilicate. The pre-oxidizing step may be 0.5 hours to about 100 hours. The heating step may be about 5 minutes to about 100 hours.

A fiber reinforced composite component may include interleaved fiber layers and ceramic particle layers coated with matrix material. The fiber reinforced composite component may be fabricated by forming a fibrous preform, needling the fibrous preform to form a plurality of z-direction fibers, and densifying the fibrous preform. The fibrous preform may be fabricated by forming a first ceramic particle layer over a first fiber layer, disposing a second fiber layer over the first ceramic particle layer, forming a second ceramic particle layer over the second fiber layer, and disposing a third fiber layer over the second ceramic particle layer.

A method of manufacturing a coated reinforcing fiber for use in Ceramic Matrix Composites, the method comprising pre-oxidizing a plurality of silicon-based fibers selected from the group consisting of silicon carbide (SiC) fibers, silicon nitride (Si.sub.3N.sub.4) fibers, SiCO fibers, SiCN fibers, SiCNO fibers, and SiBCN fibers at between 700 to 1300 degrees Celsius in an oxidizing atmosphere to form a silica surface layer on the plurality of silicon-based fibers, forming a plurality of pre-oxidized fibers; applying a rare earth orthophosphate (REPO.sub.4) coating to the plurality of pre-oxidized fibers; and heating the plurality of REPO.sub.4 coated pre-oxidized fibers at about 1000-1500 degrees Celsius in an inert atmosphere to react the REPO.sub.4 with the silica surface layer to form a rare earth silicate or disilicate. The pre-oxidizing step may be 0.5 hours to about 100 hours. The heating step may be about 5 minutes to about 100 hours.

A method for manufacturing a part made of composite material includes forming a ceramic matrix phase in pores of a fibrous preform by pyrolysis of a cross-linked copolymer ceramic precursor, the cross-linked copolymer including a first precursor macromolecular chain of a first ceramic having free carbon, and a second precursor macromolecular chain of a second ceramic having free silicon, the first macromolecular chain being bonded to the second macromolecular chain by cross-linking bridges including a bonding structure of formula *.sup.1—X—*.sup.2; in this formula, X designates boron or aluminium, -*.sup.1 designates the bond to the first macromolecular chain and -*.sup.2 the bond to the second macromolecular chain.

Fiber tows including a heat-activatable sizing are described. The sizing compositions have a first modulus at 25° C. of at least 150 megapascals (MPa) and no greater than 400 MPa; and a second modulus of 100,000 pascals (Pa) at a temperature of no greater than 160° C. Methods of preparing articles from such sized fiber tows and the articles comprising such sized fiber tows, including unidirectional and bidirectional constructions are also described.

This innovation provides for a revolutionary advancement in the area of very thick and very high thermal conductivity carbon-carbon (C—C) composites for both commercial and military. Novel, surface treated to achieve desired chemistry, exhibiting no agglomeration, carbon-based fillers are used enabling stable slurries up to 45 wt % solids to be used in the composite pre-pregging for 1-D and 2-D, 2-5 D and 3-D preforms infiltration. The need for carbonization is eliminated. No closed porosity C—C composites are produced. Up to 12″ thick C—C composites with no density gradient and thermal conductivity in excess of 650 W/mK were fabricated via chemically induced graphitization.

Methods for producing oxide/metal composite components for use in high temperature systems, and components produced thereby. The methods use a fluid reactant and a porous preform that contains a solid oxide reactant. The fluid reactant contains yttrium as a displacing metal and the solid oxide reactant of the preform contains niobium oxide, of which niobium cations are displaceable species. The preform is infiltrated with the fluid reactant to react its yttrium with the niobium oxide of the solid oxide reactant and produce an yttria/niobium composite component, during which yttrium at least partially replaces the niobium cations of the solid oxide reactant to produce yttria and niobium metal, which together define a reaction product. The pore volume of the preform is at least partially filled by the reaction product, whose volume is greater than the volume lost by the solid oxide reactant as a result of reacting yttrium and niobium oxide.

A method for producing the component, and to the use of the component. The method for producing a three-dimensional, ceramic component containing silicon carbide, by a) providing a powdery composition having a grain size (d50) between 3 microns and 500 microns and comprising at least 50 wt % of coke, b) providing a liquid binder, c) depositing a layer of the material provided in a) in a planar manner and locally depositing drops of the material provided in b) onto said layer and repeating step c), the local depositing of the drops in the subsequent repetitions of the step is adapted in accordance with the desired shape of the component to be produced, d) at least partially curing or drying the binder and obtaining a green body having the desired shape of the component, e) carbonising the green body, and f) siliconising the carbonised green body by infiltration with liquid silicon.

Methods for fabricating high-temperature composite structures (e.g., structures comprising carbon-carbon composite materials or ceramic composite matrix (CMC) materials and configured for use at temperature at or exceeding about 2000° F. (1093° C.)) include forming precursor structures by additive manufacturing (“AM”) (e.g., “3D printing”). The precursor structures are exposed to high temperatures to pyrolyze a precursor matric material of the initial 3D printed structure. A liquid resin is used to impregnate the pyrolyzed structure, to densify the structure into a near-net final shape. Use of expensive and time-consuming molds and post-processing machining may be avoided. Large, unitary, integrally formed parts conducive for use in high-temperature environments may be formed using the methods of the disclosure.

The present disclosure relates to a method of fabricating a ceramic composite components. The method may include providing at least a first layer of reinforcing fiber material which may be a pre-impregnated fiber. An additively manufactured component may be provided on or near the first layer. A second layer of reinforcing fiber, which may be a pre-impregnated fiber may be formed on top the additively manufactured component. A precursor is densified to consolidates at least the first and second layer into a densified composite, wherein the additively manufactured material defines at least one cooling passage in the densified composite component.