The present invention provides a gallium nitride sintered body and a gallium nitride molded article which have high density and low oxygen content without using a special apparatus. According to the first embodiment, a gallium nitride sintered body, which is characterized by having density of 2.5 g/cm.sup.3 to less than 5.0 g/cm.sup.3 and an intensity ratio of the gallium oxide peak of the (002) plane to the gallium nitride peak of the (002) plane of less than 3%, which is determined by X-ray diffraction analysis, can be obtained. According to the second embodiment, a metal gallium-impregnated gallium nitride molded article, which is characterized by comprising a gallium nitride phase and a metal gallium phase that exist as separate phases and having a molar ratio, Ga/(Ga+N), of 55% to 80%, can be obtained.

Disclosed are a coating for glass molding, a preparation method and application thereof and a mold having the coating. The coating includes a nitride layer and nano precious metal particles which are dispersed in the nitride layer. A surface roughness of the coating is 2-12 nm. The preparation method of the coating includes: cleaning a substrate and targets under an inert gas; and under a mixed atmosphere of nitrogen and the inert gas, depositing, with a high-purity W target, a high-purity Cr target and a precious metal inserted Cr target, a Cr intermediate layer, a nitride layer and nano precious metal particles on a surface of the substrate. The coating has good oxidation resistance and excellent anti-adhesion property. Moreover, the coating effectively inhibits the adhesion between the glass body and the mold.

A method of forming a doped substrate comprises heating a substrate comprising a layer of a dopant on at least one surface to a predetermined temperature; applying a predetermined degree of isostatic external pressure on the surface of said substrate at said predetermined temperature for a time sufficient to induce thermal migration of the dopant into the substrate to provide a doped substrate; and removing the isostatic pressure and cooling the doped substrate to about room temperature. The substrate is a glass material, a single crystal material, a poly-crystalline material, a ceramic material, or a semiconductor material, and the substrate may be optically transparent. The dopant comprises one or more transition metals, one or more rare earth elements, or a combination of both. The layer of a dopant comprises one or more segregated layers of distinct chemical species. The isostatic pressure and elevated temperature may be applied simultaneously or sequentially.

An object is to provide metal element-having ceramic continuous fibers suitable for use in the production of highly heat-resistant CMCs, and a CMC made therewith. The ceramic continuous fibers comprise ceramic continuous fibers and at least one metal element therein, with the concentration by mass of the metal element being 10 ppm or more and 1000 ppm or less.

A cemented tungsten carbide body is formed by mixing a tungsten carbide powder and a cobalt powder together to form a powder mixture. The tungsten carbide powder makes up greater than or equal to 80 weight percent of the powder mixture, while the cobalt binder powder makes up about 1.5 weight percent to about 20 weight percent of the powder mixture. Next, the powder mixture is compacted to form a green compact, and a boron nitride coating is applied to a surface of the green compact to form a coated compact. The coated compact is sintered at a temperature sufficient to melt the cobalt powder, such that boron from the boron nitride coating diffuses into the compact and creates a gradient of metallic cobalt and boron extending inward from the surface. The metallic cobalt content increases from the surface inward, while the boron content decreases from the surface inward.

A method for producing a metal-ceramic substrate with a plurality of electrically conductive vias includes: attaching a first metal layer in a planar manner to a first surface side of a ceramic layer; after attaching the first metal layer, introducing a copper hydroxide or copper acetate brine into a plurality of holes in the ceramic layer delimiting a via, to form an assembly; converting the copper hydroxide or copper acetate brine into copper oxide; subjecting the assembly to a high-temperature step above 500° C. in which the copper oxide forms a copper body in the plurality of holes; and after converting the copper hydroxide or copper acetate brine into the copper oxide, attaching a second metal layer in a planar manner to a second surface side of the ceramic layer opposite the first surface side. The copper body produces an electrically conductive connection between the first and the second metal layers.

Channel boxes for a boiling water reactor and methods of manufacture thereof are provided. The channel box comprises a substrate and a first layer. The substrate comprises a tubular shape. The substrate comprises silicon carbide fibers. The first layer is deposited on a first surface of the substrate and the first layer comprises a corrosion resistant metallic composition.

A method for selectively metallizing a surface of a ceramic substrate, a ceramic product and use of the ceramic product are provided. The method comprises steps of: A) molding and sintering a ceramic composition to obtain the ceramic substrate, in which the ceramic composition comprises a ceramic powder and a functional powder dispersed in the ceramic powder; the ceramic powder is at least one selected from a group consisting of an oxide of E, a nitride of E, a oxynitride of E, and a carbide of E; E at least one selected from a group consisting of Li, Na, K, Rb, Cs, Be, Mg, Ca, Sr, Ba, B, Al, Ga, Si, Ge, P, As, Sc, Y, Zr, Hf, is and lanthanide elements; the functional powder is at least one selected from a group consisting of an oxide of M, a nitride of M, a oxynitride of M, a carbide of M, and a simple substance of M; and M is at least one selected from a group consisting of Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Cd, Ta, W, Re, Os, Ir, Pt, Au, In, Sn, Sb, Pb, Bi, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu; B) radiating a predetermined region of the surface of the ceramic substrate using an energy beam to form a chemical plating active center on the predetermined region of the surface of the ceramic substrate; and C) performing chemical plating on the ceramic substrate formed with the chemical plating active center to form a metal layer on the predetermined region of the surface of the ceramic substrate.

Thermally-conductive ceramic and ceramic composite components suitable for high temperature applications, systems having such components, and methods of manufacturing such components. The thermally-conductive components are formed by a displacive compensation of porosity (DCP) process and are suitable for use at operating temperatures above 600° C. without a significant reduction in thermal and mechanical properties.

Thermally-conductive ceramic and ceramic composite components suitable for high temperature applications, systems having such components, and methods of manufacturing such components. The thermally-conductive components are formed by a displacive compensation of porosity (DCP) process and are suitable for use at operating temperatures above 600° C. without a significant reduction in thermal and mechanical properties.