A process for manufacturing a ceramic matrix composite part, includes infiltrating a fibrous structure including a powder composition with a melt infiltration composition including at least silicon in order to form a ceramic matrix in the porosity of the fibrous structure, the powder composition including at least silicon carbide particles, wherein the silicon carbide particles have a bimodal size distribution with a first set of silicon carbide particles having a first average size and a second set of silicon carbide particles having a second average size smaller than the first average size, the number of particles in the first set being greater than the number of particles in the second set.

A complex ceramic particle and ceramic composite material may be made of a pretreated coal dust and a polymer derived ceramic that is mixed together and pyrolyzed in a nonoxidizing atmosphere. Constituent portions of the particle mixture chemically react causing particles to increase in density and reduce in size during pyrolyzation, yielding a particle suitable for a plurality of uses including composite articles and proppants.

Provided herein is a control method for volume fraction of multistructural isotropic fuel particles in a fully ceramic microencapsulated nuclear fuel including: preparing a mixture of silicon carbide, sintering additives, and organic binders, producing a coating body by coating multistructural isotropic fuel particles by using the prepared mixture, forming the coating body, and performing pressureless sintering on the formed coating body, wherein volume fraction of multistructural isotropic nuclear fuel particles may be controlled by controlling the coating layer thickness on multistructural isotropic nuclear fuel particles, wherein the coating layer was configured with a mixture of silicon carbide, sintering additives, and organic binders. As described above, stability and tolerance against nuclear fuel related accidents may be significantly enhanced, and advantageous effects of enabling a pressureless sintering procedure to be performed while maximizing volume fraction of the multistructural isotropic fuel particles may be expected.

Methods of forming composite materials, composite materials, and articles. The composite materials may include electromagnetic shielding materials. The methods may include providing a mixture of ultra-high temperature ceramic particles and a liquid preceramic precursor, curing the mixture to form a solid mixture, forming particles of the solid mixture, and pressing the particles into a mold.

The present invention relates to a method for preparing a fully ceramic capsulated nuclear fuel material containing three-layer-structured isotropic nuclear fuel particles coated with a ceramic having a composition which has a higher shrinkage than a matrix in order to prevent cracking of ceramic nuclear fuel, wherein the three-layer-structured nuclear fuel particles before coating is included in the range of between 5 and 40 fractions by volume based on after sintering. More specifically, the present invention provides a composition for preparing a fully ceramic capsulated nuclear fuel containing three-layer-structured isotropic particles coated with the substance which includes, as a main ingredient, a silicon carbine derived from a precursor of the silicon carbide wherein a condition of ΔL.sub.c>ΔL.sub.m at normal pressure sintering is created, where the sintering shrinkage of the coating layer of the three-layer-structured isotropic nuclear fuel particles is ΔL.sub.c and the sintering shrinkage of the silicon carbide matrix is ΔL.sub.m; material produced therefrom; and a method for manufacturing the material. The residual porosity of the fully ceramic capsulated nuclear fuel material is 4% or less.

The present invention relates to a method for preparing a fully ceramic capsulated nuclear fuel material containing three-layer-structured isotropic nuclear fuel particles coated with a ceramic having a composition which has a higher shrinkage than a matrix in order to prevent cracking of ceramic nuclear fuel, wherein the three-layer-structured nuclear fuel particles before coating is included in the range of between 5 and 40 fractions by volume based on after sintering. More specifically, the present invention provides a composition for preparing a fully ceramic capsulated nuclear fuel containing three-layer-structured isotropic particles coated with the substance which includes, as a main ingredient, a silicon carbine derived from a precursor of the silicon carbide wherein a condition of ΔL.sub.c>ΔL.sub.m at normal pressure sintering is created, where the sintering shrinkage of the coating layer of the three-layer-structured isotropic nuclear fuel particles is ΔL.sub.c and the sintering shrinkage of the silicon carbide matrix is ΔL.sub.m; material produced therefrom; and a method for manufacturing the material. The residual porosity of the fully ceramic capsulated nuclear fuel material is 4% or less.

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.

A process for manufacturing a ceramic matrix composite part, includes infiltrating a fibrous structure including a powder composition with a melt infiltration composition including at least silicon in order to form a ceramic matrix in the porosity of the fibrous structure, the powder composition including at least silicon carbide particles, wherein the silicon carbide particles have a bimodal size distribution with a first set of silicon carbide particles having a first average size and a second set of silicon carbide particles having a second average size smaller than the first average size, the number of particles in the first set being greater than the number of particles in the second set.

A process for manufacturing a composite material part including a particulate reinforcement densified by a ceramic matrix, the process including: formation of a blank of the part to be manufactured by shaping a mixture including a binder, first ceramic or carbon particles intended to form the particulate reinforcement of the part and second ceramic or carbon particles distinct from the first particles, removal or pyrolysis of the binder present in the blank to obtain a porous preform of the part to be manufactured, and infiltration of the porosity of the preform by a molten composition including a metal in order to obtain the part.

The present invention relates to a method for preparing a fully ceramic capsulated nuclear fuel material containing three-layer-structured isotropic nuclear fuel particles coated with a ceramic having a composition which has a higher shrinkage than a matrix in order to prevent cracking of ceramic nuclear fuel, wherein the three-layer-structured nuclear fuel particles before coating is included in the range of between 5 and 40 fractions by volume based on after sintering. More specifically, the present invention provides a composition for preparing a fully ceramic capsulated nuclear fuel containing three-layer-structured isotropic particles coated with the substance which includes, as a main ingredient, a silicon carbine derived from a precursor of the silicon carbide wherein a condition of ΔL.sub.c>ΔL.sub.m at normal pressure sintering is created, where the sintering shrinkage of the coating layer of the three-layer-structured isotropic nuclear fuel particles is ΔL.sub.c and the sintering shrinkage of the silicon carbide matrix is ΔL.sub.m; material produced therefrom; and a method for manufacturing the material. The residual porosity of the fully ceramic capsulated nuclear fuel material is 4% or less.