A molding tool made of carbon or graphite, namely a casting mold or a casting core for the processing of molten metal or to a molding tool for the processing of molten glass, such as for example a blow mold and a method for producing the molding tool.

The present invention discloses a polyimide-based composite carbon film with high thermal conductivity and a preparation method therefor. The preparation method includes: uniformly coating the surface of a polyimide-based carbon film with an aqueous graphene oxide solution, and then covering the same with another polyimide-based carbon film uniformly coated with an aqueous graphene oxide solution; repeating such operation; after the polyimide-based carbon films are dried, bonding the polyimide-based carbon films by means of graphene oxide so as to form a thick film; bonding the polyimide-based carbon films more tightly by means of further low-temperature hot pressing; and finally, obtaining a thick polyimide-based carbon film with high thermal conductivity by repairing defects by means of low-temperature heating pre-reduction and high-temperature and high-pressure thermal treatment. The thick polyimide-based carbon film with high thermal conductivity has a thickness greater than 100 μm and an in-plane thermal conductivity of even reaching 1700 W/mK or above.

A process for manufacturing pyrocarbon, includes forming pyrocarbon by a calefaction process from at least one C.sub.2 to C.sub.6 alcohol or polyalcohol precursor, the precursor being ethanol, rough laminar pyrocarbon being obtained by imposing a temperature of between 1250° C. and 1325° C. during calefaction.

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.

Provided is a ZrO.sub.2—CaO—C based refractory material which is capable of maintaining high adhesion resistance over a long period of time, while exhibiting significant slaking resistance, and suppressing self-fluxing, i.e., exhibiting corrosion-erosion resistance. The refractory material comprises a CaO—ZrO.sub.2 composition containing a CaO component in an amount of 40% by mass to 60% by mass, wherein a mass ratio of the CaO component to a ZrO.sub.2 component is 0.67 to 1.5, and wherein the CaO—ZrO.sub.2 composition includes a eutectic microstructure of CaO crystals and CaZrO.sub.3 crystals, wherein a width of each of the CaO crystals observable in a cross-sectional microstructure is 50 μm or less.

The present disclosure provides a method of making a ceramic article. The method includes (a) obtaining a photopolymerizable slurry or sol including a plurality of ceramic particles distributed in the photopolymerizable slurry or sol and (b) selectively polymerizing the photopolymerizable slurry or sol using actinic radiation and continuous movement of a build substrate through the photopolymerizable slurry or sol to form a gelled article. The method also includes (c) extracting solvent from the gelled article to form an aerogel article or a xerogel article; (d) heat treating the aerogel article or the xerogel article to form a porous ceramic article; and (e) sintering the porous ceramic article to form a sintered ceramic article. The sintered ceramic article exhibits a particular density. Further, additive manufactured ceramic articles are provided that exhibit a particular density, opacity, or both. Preferably, all cross-sectional portions of an interior of the ceramic article having selected dimensions are free of a frequency analysis signal maxima larger than a background signal.

The present disclosure relates to a ceramic component including a boron carbide, wherein a difference of a first residual stress measured at a first spot on a surface of the ceramic component and a second residual stress measured at a second spot on the surface having different distance from a center of the surface than the first spot is −600 to +600 MPa.

A method of forming a ceramic matrix composite with being impregnated with molten metal includes: stacking a plurality of fiber layers that are layers of reinforced fibers impregnated with base resin to form a laminate in which a matrix layer containing fibers extending in a direction of impregnation with the molten metal is disposed between the fiber layers; forming an impregnation path in the matrix layer entirely in an in-plane direction perpendicular to a direction of the stacking in the laminate by carbonizing the formed laminate; and impregnating, with the molten metal, the laminate in which the impregnation path has been formed.

Disclosed herein are a polyimide film for graphite sheets and a graphite sheet manufactured using the same. The polyimide film is fabricated by imidizing a precursor composition including: a polyamic acid prepared by reacting a dianhydride monomer with a diamine monomer; and an organic solvent, wherein the diamine monomer includes about 30 mol % to about 70 mol % of 4,4′-methylenedianiline and about 30 mol % to about 70 mol % of 4,4′-oxydianiline based on the total number of moles of the diamine monomer, 4,4′-methylenedianiline and 4,4′-oxydianiline being present in total in an amount of about 85 mol % or more based on the total number of moles of the diamine monomer.

Embodiments relate to an improved hydroflux assisted densification process that introduces a transport phase (formed by the introduction of water during the process to suppress melting temperatures) for sintering, the transport phase being a non-aqueous solution. The process can facilitate sintering at low temperature ranges (at or below 300° C.) to yield densification>90% without the need for additional post-processing steps that otherwise would be needed if conventional processes were used. Control of the pressures and water content used during the process can enhance densification mechanisms related to dissolution-reprecipitation, allowing for a greater range of compositional spectra of materials that can be densified, a reduction of the amount of transport phase needed, a reduction of impurities and an improvement of properties in the densified material. Certain hydrated acetate powders can be used to generate a hydroxide mixture flux that is better for the low-temperature densification process.