This patent document relates to systems, structures, devices, and fabrication processes for ceramic matrix composites suitable for use in a nuclear reactor environment and other applications requiring materials that can withstand high temperatures and/or highly corrosive environments. In one exemplary aspect, a method of joining and sealing ceramic structures is disclosed. The method comprises forming a joint of a ceramic structure and an end plug using a sealing material, wherein the end plug has a hole that goes through a top surface and a bottom surface of the end plug; filling the ceramic structure with a desired gas composition through the hole; heating a material into a molten form using a heat source; and directing the material into the hole, wherein the material solidifies to seal the end plug.

Disclosed herein is a dual density disc comprising a dense outer tube comprising alumina having a purity of greater than 99%; and a porous core comprising alumina of a lower density than a density of the dense outer tube; wherein the porous core has an alumina purity of greater than 99%. Disclosed herein too is method comprising disposing in a dense outer tube a slurry comprising alumina powder and a pore former; heating the dense outer tube with the slurry disposed therein to a temperature of 300 to 600? C. to activate the pore former; creating a porous core in the dense outer tube; and sintering the dense outer tube with the porous core at a temperature of 800 to 2000? C. in one or more stages.

A layered body, which has a change in texture derived from zirconia, particularly a change in translucency and is suitable as a dental prosthetic member, a precursor thereof, or a method for producing these. The layered body has a structure in which two or more layers containing zirconia containing a stabilizer are layered, the layered body including at least: a first layer containing zirconia having a stabilizer content of higher than or equal to 4 mol %; and a second layer containing zirconia having a stabilizer content different from that of the zirconia contained in the first layer. At least one layer contains one or more elements capable of coloring zirconia.

The invention relates to a process for metallizing ferrite ceramics, which comprises the following steps: arrangement of a. contact element composed of copper or a copper alloy on a surface of the ferrite ceramic, melting of the contact element at least in the region in which the contact element contacts the surface of the ferrite ceramic, and cooling of the contact element and the ferrite ceramic to below the melting point of copper or the copper alloy.

A layered body, which has a change in texture derived from zirconia, particularly a change in translucency and is suitable as a dental prosthetic member, a precursor thereof, or a method for producing these. The layered body has a structure in which two or more layers containing zirconia containing a stabilizer are layered, the layered body including at least: a first layer containing zirconia having a stabilizer content of higher than or equal to 4 mol %; and a second layer containing zirconia having a stabilizer content different from that of the zirconia contained in the first layer. At least a first layer and a second layer contain an element having a function of coloring zirconia and the content or the type of the element having a function of coloring zirconia in the first layer is different from the element having a function of coloring zirconia in the second layer.

The present invention relates to a sealing lid for a package containing an optical element. For the sealing lid, a translucent material such as glass that can transmit light such as visible light is used. The present invention includes a lid main body made of the translucent material. The lid main body includes a joining region having a frame shape corresponding to an outer circumferential shape of the lid main body. A plurality of pieces of brazing material made of a eutectic alloy are fused on the joining region of the lid main body. An arrangement state of the brazing material includes aligning spherical pieces of brazing material continuously to form a frame shape along the joining region.

A method for joining materials, includes: providing a first material and a second material, providing the first material with a grid structure at a joining point, and joining, in particular soldering, the second material to the grid structure such that a material composite of the first material and the second material is produced, wherein the grid structure is designed in such a way that stresses in the material composite are at least partly compensated by the grid structure.

The invention relates to a method of making a sink comprising: cutting out material that will constitute a bottom of the sink; making a hole for a drain in the bottom of the sink; supporting the edges of the bottom of the sink on a flat support and applying a mechanical force on the rim of the hole for the drain in the bottom of the sink; subjecting the bottom of the sink to a gradual and stepwise heating such that the mechanical force applied deforms said surface; cooling a flat slab; placing additional flat slabs around the first slab, on the sides thereof, to constitute the sides of the sink; externally coating the assembly made with a reinforcement comprising resins, glass fiber, mineral fillers, etc.; and bonding the upper part of the assembly made with the countertop where the sink is located.

A copper/ceramic bonded body is provided, including: a copper member made of copper or a copper alloy; and a ceramic member, the copper member and the ceramic member being bonded to each other, in which a total concentration of Al, Si, Zn, and Mn is 3 atom % or less when concentration measurement is performed by an energy dispersive X-ray analysis method at a position 1000 nm away from a bonded interface between the copper member and the ceramic member to a copper member side, assuming that a total value of Cu, Mg, Ti, Zr, Nb, Hf, Al, Si, Zn, and Mn is 100 atom %.

A method of producing a ceramic sheet includes: shaping a composition containing a resin and a ceramic material into a sheet-like form through pressure application to perform primary sheet shaping; stacking a plurality of the primary sheet in a thickness direction or performing folding or winding of the primary sheet to obtain a laminate; slicing the laminate at an angle of 45 or less relative to a stacking direction to obtain a secondary sheet; and firing the secondary sheet.