A nonwoven article includes a plurality of electrospun polycrystalline, aluminosilicate ceramic filaments that form a cohesive nonwoven mat. Each of the aluminosilicate ceramic filaments in the mat have an average diameter of about 200 nm to about 1000 nm as determined with electron microscopy, and the aluminosilicate ceramic filaments have an average crystalline mullite content of about 15 wt % to about 80 wt %.

A method for manufacturing ceramic matrix composites (CMC) and CMCs made by the method are disclosed. The method can be a manual process or an automated process, such as using a robotic system, that is used for controlled delivery of ceramic particles in a CMC fabric. The method includes identifying voids present between adjacent tows of the CMC fabric and dispensing ceramic particles into the voids. Applying the ceramic particles in the center of the voids reduces the size and volume fraction of the voids/defects, improving the homogeneity of surface texture of the preform, homogeneity of microstructure, and part model shape conformity. The method for manufacturing CMCs creates CMCs having a homogenous distribution of small pores after matrix formation that improves the interlaminar mechanical and thermal properties of the CMCs.

A method for making a high temperature composite, which is a carbon carbon composite, carbon fiber reinforced ceramic matrix composite, ceramic fiber reinforced ceramic matrix composite, or a carbon silica composite, including: a) providing a precursor part including a resin comprising a poly(aryl ether ketone) (PAEK) and at least one reinforcing material, wherein the resin has a degree of crystallinity of 10% or more; b) pyrolyzing the precursor part to a pyrolyzed part; c) infusing a liquid second resin into the pyrolyzed part to make an infused part; and d) pyrolyzing the infused part to make the carbon carbon composite carbon fiber reinforced ceramic matrix composite, ceramic fiber reinforced ceramic matrix composite, or the carbon silica composite, optionally repeating steps c. through d. Also, a carbon carbon composite, carbon fiber reinforced ceramic matrix composite, ceramic fiber reinforced ceramic matrix composite, or carbon silica composite made by the method.

Methods of forming a metallic-ceramic brazed joint are disclosed herein. The method of forming the brazed joint includes deoxidizing the surface of metallic components, assembling the joint, heating the joint to fuse the joint components, and cooling the joint. In certain embodiments, the brazed joint includes a conformal layer. In further embodiments, the brazed joint has features in order to reduce stress concentrations within the joint.

A method of preparing a woven fabric material for use in a ceramic matrix composite includes passing a desized woven fabric tape having a first inter-filament spacing through a dispersal module configured to transform the desized woven fabric tape into a dispersed woven fabric tape having a second inter-filament spacing greater than the first inter-filament spacing. The dispersal module includes a first charging element with a charged surface and disposed to apply an electric charge to the desized woven fabric tape. The method further includes applying a polymer binder to the dispersed woven fabric tape to create a stabilized woven fabric tape having the second inter-filament spacing.

A method of preparing a woven ceramic fabric for use in a ceramic matrix composite includes transforming a woven fabric sheet having a first tow architecture into a separated woven fabric sheet having a second tow architecture, the first tow architecture including a plurality of warp tows and a plurality of weft tows, and the second tow architecture including a plurality of warp subtows and/or a plurality of weft subtows. Transforming the woven fabric sheet includes separating at least some of the plurality of warp tows and/or the plurality of weft tows into a greater number of corresponding warp subtows and/or weft subtows, respectively, such that second tow architecture includes more warp subtows and/or weft subtows than the first tow architecture comprises warp tows and weft tows, and wherein each of the warp subtows and/or weft subtows includes fewer filaments than corresponding warp tow and/or weft tow. Each of the plurality of warp subtows and/or weft subtows is spaced apart from the closest adjacent warp subtow and/or weft subtow, respectively, a distance of 25 to 230 microns.

A method of preparing a woven fabric material for use in a ceramic matrix composite includes securing a woven fabric tape in tension across a roller, the roller having an outer surface with a plurality of spiked protrusions extending radially therefrom, each of the plurality of spiked protrusions having a diameter between 10 microns and 500 microns. The method further includes passing the woven fabric along the roller, such that the roller rotates with the passing of the woven fabric tape, thereby impinging the spiked protrusions into the woven fabric tape, and separating filaments within tows of the woven fabric tape by penetration of at least one of the spiked protrusions into the woven fabric tape, such that filaments within various tows of the woven fabric tape are pushed apart to form a separated woven fabric tape with a greater number of tows per unit area than the woven fabric tape.

A method for constructing multiple ceramic layers by winding continuous ceramic filaments of identical composition to prepare multilayer RF-transparent structures is provided. In the method, identical continuous ceramic filaments are wound to construct a layer with specific dielectric constant according to patterns, characterized by the winding angle, winding density/inter-fiber aperture and winding count/layer thickness. Layers with same or different dielectric characteristics forms a sandwich design to fulfill the desired mechanical, thermal and electrical requirements.

Methods of forming a ceramic matrix, as well as fiber preforms and methods of forming fiber preforms to facilitate formation of a ceramic matrix are provided. The method includes obtaining a fiber preform to facilitate forming the ceramic matrix. The fiber preform includes a fiber layer with a plurality of fibers and a heating element embedded within the fiber preform. The method also includes heating the fiber preform via the heating element embedded within the fiber preform, and depositing matrix material into the fiber preform by embedded wire chemical vapor deposition (EWCVD) of the matrix material during the heating of the fiber preform by the heating element. The chemical vapor deposition of the matrix material within the fiber preform facilitates formation of the ceramic matrix.

A method for manufacturing a C/C part includes fabricating an oxidized PAN fiber preform comprising a stack of sheets of multi-axial, non-crimp, OPF fabric. The method includes positioning the oxidized PAN fiber preform with a female forming tool, the female forming tool comprising a die recess, and forming the oxidized PAN fiber preform into a shaped body. The shaped body is removed from the female forming tool and moved into a graphite fixture for carbonization. The carbonized shaped body may also be densified into the final C/C part. The carbonized shaped body can also be placed in a perforated graphite fixture for densification and removed from the perforated graphite fixture between densification processes for machining and for facilitating further densification.