The disclosed methods and apparatus improve the fabrication of solid fibers and microstructures. In many embodiments, the fabrication is from gaseous, solid, semi-solid, liquid, critical, and supercritical mixtures using one or more low molar mass precursor(s), in combination with one or more high molar mass precursor(s). The methods and systems generally employ the thermal diffusion/Soret effect to concentrate the low molar mass precursor at a reaction zone, where the presence of the high molar mass precursor contributes to this concentration, and may also contribute to the reaction and insulate the reaction zone, thereby achieving higher fiber growth rates and/or reduced energy/heat expenditures together with reduced homogeneous nucleation. In some embodiments, the invention also relates to the permanent or semi-permanent recording and/or reading of information on or within fabricated fibers and microstructures. In some embodiments, the invention also relates to the fabrication of certain functionally-shaped fibers and microstructures. In some embodiments, the invention may also utilize laser beam profiling to enhance fiber and microstructure fabrication.

A crystalline silicon carbide fiber containing silicon carbide and boron nitride, the crystalline silicon carbide fiber having a content of Si of 64% to 72% by weight, a content of C of 28% to 35% by weight, and a content of B of 0.1% to 3.0% by weight, and including, at a surface portion, a composition gradient layer in which a content of silicon carbide increases while a content of boron nitride decreases toward a depth direction.

The present invention is a method for obtaining a ceramic slurry for the production of filaments for 3D FDM printing, comprising adding a polysaccharide, a glycol or an ethanolamine as a gelling agent to a suspension of ceramic material in order to produce said ceramic slurry. The invention also comprises the green body obtained from said slurry and the ceramic filament extruded from the green body.

A multi-composition fiber is provided including a primary fiber material and an elemental additive material deposited on grain boundaries between adjacent crystalline domains of the primary fiber material. A method of making a multi-composition fiber is also provided, which includes providing a precursor laden environment, and promoting fiber growth using laser heating. The precursor laden environment includes a primary precursor material and an elemental precursor material.

A ceramic matrix composite of the present disclosure includes a fiber substrate including a silicon carbide fiber bundle, and a silicon carbide film formed on a surface of each silicon carbide fiber of the silicon carbide fiber bundle, in which a ratio of an average film thickness D.sub.2 to an average film thickness Di is 1.0 to 1.3, the average film thickness Di being an average film thickness of the silicon carbide film formed on a surface of the silicon carbide fiber in an outer layer of the silicon carbide fiber bundle, and the average film thickness D.sub.2 being an average film thickness of the silicon carbide film formed on a surface of the silicon carbide fiber in an inner layer, which is positioned inside the outer layer, of the silicon carbide fiber bundle.

A method of forming a high purity granular material, such as silicon carbide powder. Precursors are added to a reactor; at least part of a fiber is formed in the reactor from the precursors using chemical deposition interacting with said precursors; and the granular material is then formed from the fiber. In one aspect, the chemical deposition may include laser induced chemical vapor deposition. The granular material may be formed by grinding or milling the fiber into the granular material, e.g., ball milling the fiber. In one example, silicon carbide powder having greater than 90% beta crystalline phase purity and less than 0.25% oxygen contamination can be obtained.

Provided are a SiC/ZrC composite fiber, a preparation method and use thereof. The SiC/ZrC composite fiber has a diameter of 10 to 70 μm. The method includes mixing liquid polycarbosilane with a zirconium-containing polymer to obtain a hybrid spinning solution, and then performing electrospinning to obtain a SiC/ZrC composite fiber precursor, crosslinking and thermally treating the SiC/ZrC composite fiber precursor in a protective atmosphere to obtain the SiC/ZrC composite fiber. The SiC/ZrC composite fiber is continuous and uniform, has an adjustable diameter, and thus has outstanding tensile strength and breaking strength and excellent high-temperature resistance. Without use of any organic solvent or spinning agent, the method achieves short process flow and high yield, indicating wide application prospects.

Methods of producing silicon carbide, and other metal carbide materials. The method comprises reacting a carbon material (e.g., fibers, or nanoparticles, such as powder, platelet, foam, nanofiber, nanorod, nanotube, whisker, graphene (e.g., graphite), fullerene, or hydrocarbon) and a metal or metal oxide source material (e.g., in gaseous form) in a reaction chamber at an elevated temperature ranging up to approximately 2400° C. or more, depending on the particular metal or metal oxide, and the desired metal carbide being produced. A partial pressure of oxygen in the reaction chamber is maintained at less than approximately 1.01×10.sup.2 Pascal, and overall pressure is maintained at approximately 1 atm.

The present invention relates to a process for the preparation of a ceramic nanowire preform, in particular to a process for the preparation of the ceramic nanowire preform by combining a template technique and a preceramic polymer conversion technique. The process of the present invention uses carbonaceous material as a template, and prepares an isotropic ceramic nanowire preform by controlling the ratio of a precursor to a solvent, the amount of a catalyst and the ratio of a prepared precursor solution to the carbonaceous template, wherein the preform is isotropic and has lower bulk density and higher volume fraction.

Disclosed is a coated ceramic fiber including a zirconium interface coating layer deposited on the ceramic fiber, a zirconium dioxide interface coating layer adjacent to the zirconium interface coating layer, and an additional interface coating layer adjacent to the zirconium dioxide interface coating layer, wherein zirconium dioxide interface coating layer forms micro cracks after a crystal structure transformation. The coated ceramic fiber may be included in a composite material having a ceramic matrix.