Compositions comprising preceramic resins and fumed alumina are described. The compositions can also include fillers, such as silicon carbide whiskers or zirconium diboride particles. The compositions can be used as three-dimensional printable inks for preparing ceramic composites, e.g., composites having complex geometry. Inclusion of fumed alumina as a rheology modifier in the composition can provide improved printing properties for the inks compared to preceramic resin inks that do not include fumed alumina.

In one aspect, the disclosure relates to nanocomposite radome materials incorporating boron nitride materials in a polymer derived ceramic matrix. In another aspect, the nanocomposite radome materials have superior electrochemical performance, excellent mechanical strength and stability, corrosion resistance and transparency to electromagnetic radiation, methods of making the same, and articles and components incorporating the same. In one aspect, the nanocomposite radome materials retain functionality in the presence of significant amounts of moisture. This abstract is intended as a scanning tool for purposes of searching in the particular art and is not intended to be limiting of the present disclosure.

A method for constructing a plurality of ceramic layers by winding continuous ceramic filaments to prepare RF-transparent structures is provided. Dielectric properties of each layer of the plurality of ceramic layers are characterized by an inter-filament spacing, a filament count and thickness. Once the plurality of ceramic layers are constructed, a structure is removed from a winding surface, wherein the winding surface is a mandrel, infiltrated with a resin in a separate set up and fired.

Disclosed is a ceramic matrix component having a fibrous core and a ceramic matrix composite shell surrounding at least a portion of the fibrous core. The ceramic matrix composite shell comprises a fibrous preform. The fibrous core has a greater porosity than the fibrous preform. A method of making the ceramic matrix component is also disclosed.

A method for forming a ceramic matrix composite (CMC) component with an internal cooling channel includes partially densifying a first fiber preform to form a portion of a final ceramic matrix volume, machining a first channel into a surface of the partially densified first fiber preform, covering the first channel with a fibrous member to form a near net shape fiber preform with an internal passage formed by the first channel and the fibrous member, and densifying the near net shape fiber preform.

A method of forming a structure comprising a continuous fiber material comprises continuously feeding, through a continuous fiber nozzle assembly of an additive manufacturing tool, a feed material comprising a continuous fiber material and a thermoset resin material, heating or cooling the feed material to maintain a temperature of the feed material to a temperature sufficient to tackify the feed material and at least partially cure the feed material and initiate adhesion of the feed material on a build platform or a previously formed portion of a structure, and moving the continuous fiber nozzle assembly in three dimensions while depositing the feed material on the build platform or the previously formed portion of the structure to form the structure comprising the continuous fiber material extending in three dimensions. Related methods of forming a composite structure, and related tools for additively manufacturing a structure are disclosed.

Disclosed herein is a ceramic matrix composite comprising a preform comprising a plurality of plies; a ceramic matrix encompassing the plies and distributed through the plies; and thermally conducting particles distributed through the ceramic matrix. Disclosed herein is a method comprising distributing thermally conducting particles between plies in a preform; infiltrating chemical vapors of a ceramic precursor into the plies; and reacting the ceramic precursor to form a matrix.

Disclosed herein is a composite ply comprising fill and warp tows; or optional axial and bias tows; wherein one or more of the fill tows and/or the warp tows or wherein one or more of the optional axial and/or bias tows comprise a polymer yarn while the remaining portion of the fill tows and/or the warp tows or the remaining portion of the bias and/or optional axial tows comprise the polymer yarn; and wherein the polymer yarn is melted to bond to the fill or warp tows to prevent removal from the ply.

A composite article comprises a substrate, the substrate comprising a silicon containing material and an additive comprising boron nitride nanotubes.

Disclosed herein is a composite comprising a ceramic matrix composite comprising a ceramic matrix and ceramic fibers; and one or more sacrificial fibers woven into the ceramic matrix composite; where the sacrificial fibers are operative to undergo oxidation or melting upon being subjected to an elevated temperature; and wherein the sacrificial fibers leave cooling holes in the composite preform upon being subjected to oxidation or melting.