This invention provides resin formulations which may be used for 3D printing and pyrolyzing to produce a ceramic matrix composite. The resin formulations contain a solid-phase filler, to provide high thermal stability and mechanical strength (e.g., fracture toughness) in the final ceramic material. The invention provides direct, free-form 3D printing of a preceramic polymer loaded with a solid-phase filler, followed by converting the preceramic polymer to a 3D-printed ceramic matrix composite with potentially complex 3D shapes or in the form of large parts. Other variations provide active solid-phase functional additives as solid-phase fillers, to perform or enhance at least one chemical, physical, mechanical, or electrical function within the ceramic structure as it is being formed as well as in the final structure. Solid-phase functional additives actively improve the final ceramic structure through one or more changes actively induced by the additives during pyrolysis or other thermal treatment.

This disclosure provides systems, methods, and apparatus related to boron nitride nanomaterials. In one aspect, a method includes generating a directed flow of plasma. A boron-containing species is introduced to the directed flow of the plasma. Boron nitride nanostructures are formed in a chamber. In another aspect, a method includes generating a directed flow of plasma using nitrogen gas. A boron-containing species is introduced to the directed flow of the plasma. The boron-containing species can consist of boron powder, boron nitride powder, and/or boron oxide powder. Boron nitride nanostructures are formed in a chamber, with a pressure in the chamber being about 3 atmospheres or greater.

An electrophoretic deposition method of forming a boron nitride (BN) nanotube interface coating on ceramic fibers has been developed. The method comprises immersing first and second electrodes in a suspension including surface-modified BN nanotubes, where the first electrode includes ceramic fibers positioned on a surface thereof. The surface-modified BN nanotubes comprise BN nanotubes with an electrically charged polymer adsorbed on surfaces thereof. A voltage is applied to the first and second electrodes, and the surface-modified BN nanotubes move toward the first electrode and deposit on the ceramic fibers. After the deposition of the surface-modified BN nanotubes, the ceramic fibers are removed from the suspension and heat treated. Accordingly, a BN nanotube interface coating is formed on the ceramic fibers.

The invention relates to a method for preparing a composite metal oxide hollow fibre. A certain stoichiometry of composite metal oxide raw material and a polymer binding agent are added to an organic solvent, and mixed mechanically to obtain an evenly dispersed spinning solution having a suitable viscosity. After defoaming treatment, the spinning solution is extruded through a spinneret and, after undergoing a certain dry spinning process, enters an external coagulation bath; during this period, a phase inversion process occurs and composite metal oxide hollow fibre blanks are formed. The blanks are immersed in the external coagulation bath and the organic solvent is displaced; after natural drying, the blanks undergo a heat treatment process; during this period, polymer burn off, in situ reaction, and in situ sintering processes occur to obtain the composite metal oxide hollow fibre.

A microstructure comprises a plurality of interconnected units wherein the units are formed of graphene tubes. The graphene tubes may be formed by photo-initiating the polymerization of a monomer in a pattern of units to form a polymer microlattice, removing unpolymerized monomer, coating the polymer microlattice with a metal, removing the polymer microlattice to leave a metal microlattice, depositing graphitic carbon on the metal microlattice, converting the graphitic carbon to graphene, and removing the metal microlattice. A ceramic may be deposited on the graphene and another graphene layer may be deposited on top of the ceramic to create a multi-layered sp.sup.2-bonded carbon tube.

This invention provides resin formulations which may be used for 3D printing and pyrolyzing to produce a ceramic matrix composite. The resin formulations contain a solid-phase filler, to provide high thermal stability and mechanical strength (e.g., fracture toughness) in the final ceramic material. The invention provides direct, free-form 3D printing of a preceramic polymer loaded with a solid-phase filler, followed by converting the preceramic polymer to a 3D-printed ceramic matrix composite with potentially complex 3D shapes or in the form of large parts. Other variations provide active solid-phase functional additives as solid-phase fillers, to perform or enhance at least one chemical, physical, mechanical, or electrical function within the ceramic structure as it is being formed as well as in the final structure. Solid-phase functional additives actively improve the final ceramic structure through one or more changes actively induced by the additives during pyrolysis or other thermal treatment.

This invention provides resin formulations which may be used for 3D printing and pyrolyzing to produce a ceramic matrix composite. The resin formulations contain a solid-phase filler, to provide high thermal stability and mechanical strength (e.g., fracture toughness) in the final ceramic material. The invention provides direct, free-form 3D printing of a preceramic polymer loaded with a solid-phase filler, followed by converting the preceramic polymer to a 3D-printed ceramic matrix composite with potentially complex 3D shapes or in the form of large parts. Other variations provide active solid-phase functional additives as solid-phase fillers, to perform or enhance at least one chemical, physical, mechanical, or electrical function within the ceramic structure as it is being formed as well as in the final structure. Solid-phase functional additives actively improve the final ceramic structure through one or more changes actively induced by the additives during pyrolysis or other thermal treatment.

The use of magnesium oxide, reactive alumina and aluminium oxide as a base provides for a new erosion-resistant material upon sintering.

A material useful as a proppant comprises a core chemically reacted in situ from coal dust and a polymer derived ceramic material, such that at least a portion of the coal dust is chemically converted to a ceramic, nanoparticles, graphene, nanofibers or combinations of any of these.

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.