A method for forming a complex shape three-dimensional ceramic article by printing a first layer of a first material having a first fraction of first ceramic particles and a first fraction of a first polymeric ceramic precursor. A second layer is printed such that it is at least partially disposed on the first layer of a second material having a second fraction of second ceramic particles and a second fraction of a second polymeric ceramic precursor. A composite of the first layer and the second layer is heated at a temperature sufficient to decompose the first and second polymeric ceramic precursors and sinter the article. During the sintering process, the first and second layers with different fractions of ceramic particles undergo different degrees of shrinkage, resulting in a tuneable mismatch of the bilayer structure and accurately achieving a targeted geometry.

A preceramic resin formulation comprising a polycarbosilane preceramic polymer and an organically modified silicon dioxide preceramic polymer. A ceramic material comprising a reaction product of the polycarbosilane preceramic polymer and organically modified silicon dioxide preceramic polymer is also described. Articles comprising the ceramic material are also described, as are methods of forming the preceramic resin formulation and the ceramic material.

A barrier coating resin formulation comprising at least one polycarbosilane preceramic polymer, at least one organically modified silicon dioxide preceramic polymer, at least one filler, and at least one solvent. A barrier coating comprising a reaction product of the at least one polycarbosilane preceramic polymer and the at least one organically modified silicon dioxide preceramic polymer and the at least one filler is also disclosed, as are articles comprising the barrier coating, rocket motors comprising the barrier coating, and methods of forming the articles.

The proposed method relates to the processing of carbon-containing raw material and may be used to obtain products containing amorphous silica and amorphous carbon of varying degrees of purity. The technical result consists in simplifying the production of a product containing amorphous silica and increasing the yield efficiency for such a product by decreasing the temperature to which the carbon-containing raw material is exposed. The method of producing a product containing amorphous silica and amorphous carbon includes the steps in which a carbon-containing raw material is dried at a temperature of 150-200° C. and the dried raw material is subjected to heat treatment at a temperature of 400-600° C., wherein the heat treatment is performed in the presence of an activator made of a readily fusible alloy. A device for carrying out the method is also proposed.

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.

Methods, apparatus and systems using heat exchanger reactors to form polymer derived ceramic materials, including methods for making polysilocarb (SiOC) precursors.

The invention relates to a pre-impregnated fibre-reinforced composite material in laminar form, obtained impregnating a fibrous mass with a polymeric binder composition and intended to be subjected to successive forming and pyrolysis operations to produce a fibre-reinforced composite ceramic material. The polymeric binder composition is based on one or more resins chosen from the group consisting of siloxane resins and silsesquioxane resins, and can optionally comprise one or more organic resins. The polymeric binder composition is a liquid with viscosity between 55000 and 10000 mPas at temperatures between 50° C. and 70° C. The polymeric binder composition forms a polymeric binding matrix, not cross-linked or only partially cross-linked that fills the interstices of the fibrous mass. The invention also relates to a method for making said pre-impregnated fibre-reinforced composite material in laminar form. The invention further relates to a fibre-reinforced composite ceramic material, obtained by forming and subsequent pyrolysis of a pre-impregnated fibre-reinforced composite material, as well as a method for making said material.

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.

A silicon nitride powder for sintering which, despite of its fine powdery form, shows a very small increase in the oxygen concentration with time and features excellent storage stability. The silicon nitride powder for sintering has a specific surface area of 5 to 30 m.sup.2/g, and is characterized by having a hydrophobicity (M value) of 30 or more and an increase in the oxygen concentration of 0.30% by mass or less after left to stand in the air of a humidity of 90% and 20° C. for 48 hours. The silicon nitride powder for sintering can be obtained by dry-pulverizing aggregated masses of the silicon nitride in an inert atmosphere in the presence of a silane coupling agent.