A nuclear reactor fuel rod is a fuel rod for a light-water reactor. The nuclear reactor fuel rod includes a fuel cladding tube and an end plug, both of which are formed of a silicon carbide material. A bonding portion between the fuel cladding tube and the end plug is formed by brazing with a predetermined metal bonding material interposed, and/or by diffusion bonding. The predetermined metal bonding material has a solidus temperature of 1200° C. or higher. An outer surface of the bonding portion, and a portion of an outer surface of the fuel cladding tube and the end plug, which is adjacent to the outer surface of the bonding portion are covered by bonding-portion coating formed of a predetermined coating metal. The predetermined metal bonding material and the predetermined coating metal have an average linear expansion coefficient which is less than 10 ppm/K.

A method for the assembly of a metal part and a ceramic part, including the following steps: supplying a solid ceramic part of the alumina type; supplying a solid metal part, the metal being selected from platinum and tantalum, or an alloy including a majority of one of these metals; depositing at least one layer, called interface layer, on at least one of the solid parts, the interface layer containing magnesium oxide; bringing into contact the solid metal part and the solid ceramic part such that the interface layer is located between the solid parts; and hot densification under pressure of the solid parts brought into contact, to create a close bond between the solid parts and form a spinel from the interface layer. An electrical device, such as a capacitive sensor having a sensitive part produced according to the present method, is also provided.

A method is described for assembling at least two parts made of silicon carbide based materials by non-reactive brazing in an oxidizing atmosphere, each of the parts comprising a surface to be assembled, wherein the parts are placed in contact with a non-reactive brazing composition, the assembly formed by the parts and the brazing composition is heated to a brazing temperature sufficient for completely or at least partially melting the brazing composition, or rendering the brazing composition viscous, and the parts and the brazing composition are cooled so as to form, after cooling the latter to ambient temperature, a moderately refractory joint. The non-reactive brazing composition is a composition A consisting of silica (SiO.sub.2), alumina (Al.sub.2O.sub.3), and calcium oxide (CaO), or a composition B consisting of alumina (Al.sub.2O.sub.3), calcium oxide (CaO), and magnesium oxide (MgO), and, before heating the assembly formed by the parts and the brazing composition to the brazing temperature, a supply of silicon in a non-oxidized form is carried out on the surfaces to be assembled of the parts to be assembled, and/or on the surface layers comprising the surfaces to be assembled of the parts to be assembled, and/or in the brazing composition.

A honeycomb structure including a plurality of porous honeycomb block bodies bound via joining material layers A. Each of the porous honeycomb block bodies includes a plurality of porous honeycomb segments bound via joining material layers B, each of the porous honeycomb segment includes: partition walls that defines a plurality of cells to form flow paths for a fluid, each of cells extending from an inflow end face that is an end face on a fluid inflow side to an outflow end face that is an end face on a fluid outflow side; and an outer peripheral wall located at the outermost periphery. At least a part of the joining material layers A has higher toughness than that of the joining material layers B.

In some examples, a method may include depositing, from a slurry comprising particles including silicon metal, a bond coat precursor layer including the particles comprising silicon metal directly on a ceramic matrix composite substrate. The method also may include locally heating the bond coat precursor layer to form a bond coat comprising silicon metal. Additionally, the method may include forming a protective coating on the bond coat. In some examples, an article may include a ceramic matrix composite substrate, a bond coat directly on the substrate, and a protective coating on the bond coat. The bond coat may include silicon metal and a metal comprising at least one of Zr, Y, Yb, Hf, Ti, Al, Cr, Mo, Nb, Ta, or a rare earth metal.

A method to produce a ceramic matrix composite with controlled surface characteristics includes: applying a scrim ply to a surface of a fiber preform, where the fiber preform includes silicon carbide fibers coated with boron nitride; infiltrating the fiber preform and the scrim ply with a slurry, thereby forming an impregnated ply on an impregnated fiber preform; infiltrating the impregnated fiber preform and the impregnated ply with a melt comprising silicon, and then cooling, thereby forming a ceramic matrix composite having a ceramic surface layer thereon, where the ceramic surface layer has a predetermined thickness and is devoid of boron; machining or grit blasting the ceramic surface layer to form an intermediate layer suitable for coating; and depositing an environmental barrier coating on the intermediate layer. Thus, a ceramic matrix composite coated with the environmental barrier coating is formed with the intermediate layer in between.

An epitaxy substrate and a method of manufacturing the same are provided. The epitaxy substrate includes a device substrate and a handle substrate. The device substrate has a first surface and a second surface opposite to each other, and a bevel disposed between the first and the second surfaces. The handle substrate is bonded to the second surface of the device substrate, wherein the oxygen content of the device substrate is less than the oxygen content of the handle substrate, and a bonding angle greater than 90° is between the bevel of the device substrate and the handle substrate.

The disclosure describes techniques for forming a surface layer of an article including a CMC using a cast. In some examples, the surface layer includes three-dimensional surface features, which may increase adhesion between the CMC and a coating on the CMC. In some examples, the surface layer may include excess material, with or without three-dimensional surface features, which is on the CMC. The excess material may be machined to remove some of the excess material and facilitate conforming the article to dimensional tolerances, e.g., for fitting the article to another component. The excess material may reduce a likelihood that the CMC (e.g., reinforcement material in the CMC) is damaged by the machining.

A heat sink-attached power module substrate board has a ratio (A1×t1×σ1×α1)/{(A2×t2×σ2×α2)+(A3×t3×σ3×α3)} at 25° C. is not less than 0.70 and not more than 1.30, where A1 (mm.sup.2) is a bonding area of a second layer and a first layer composing a circuit layer; t1 (mm) is an equivalent board thickness, σ1 (N/mm.sup.2) is yield strength, and α1 (/K) is a linear expansion coefficient, all of the second layer, where A2 (mm.sup.2) is a bonding area of the heat radiation-side bonding material and the metal layer; t2 (mm) is equivalent board thickness, σ2 (N/mm.sup.2) is yield strength, and α2 (/K) is a linear expansion coefficient, all of the heat radiation-side bonding material, and where A3 (mm.sup.2) is a bonding area of the heat sink and the heat radiation-side bonding material; t3 (mm) is equivalent board thickness, σ3 (N/mm.sup.2) is yield strength, and α3 (/K) is a linear expansion coefficient, all of the heat sink.

A method of manufacturing an epitaxy substrate is provided. A handle substrate is provided. A beveling treatment is performed on an edge of a device substrate such that a bevel is formed at the edge of the device substrate, wherein a thickness of the device substrate is greater than 100 μm and less than 200 μm. An ion implantation process is performed on a first surface of the device substrate to form an implantation region within the first surface. A second surface of the device substrate is bonded to the handle substrate for forming the epitaxy substrate, wherein a bonding angle greater than 90° is provided between the bevel of the device substrate and the handle substrate, and a projection length of the bevel toward the handle substrate is between 600 μm and 800 μm.