A sensor element (10) having a laminate structure, and extending in an axial direction AX, the sensor element including a first and second ceramic layers (118B, 115) disposed apart from each other in a laminating direction; a third ceramic layer (118) intervening between the first and second ceramic layers in the laminating direction and having a hollow space (10G) formed therein; and an internal space which is the hollow space surrounded by the first ceramic layer, the second ceramic layer, and the third ceramic layer, wherein, at a periphery (10f) of the internal space, a fourth ceramic layer (181) containing as a main component a ceramic material different from that contained as a main component in the first and third ceramic layers intervenes between the first ceramic layer and the third ceramic layer which are exposed to the internal space. Also disclosed is a method for manufacturing the gas sensor element.

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.

A ceramic capacitor includes a multilayer structure, wherein a main component of dielectric layers is ceramic expressed by a general formula A.sub.mBO.sub.3 (0.995m1.010), wherein the dielectric layers include a rare earth element Re as a first sub-component by 2.0 mol to 5.0 mol when converted into Re.sub.2O.sub.3/2, include Mg as a second sub-component by 1.0 mol to 3.0 mol when converted into MgO, include V as a third sub-component by 0.05 mol to 0.25 mol when converted into V.sub.2O.sub.5/2, include Si as a fourth sub-component by 0.5 mol to 5.0 mol when converted into SiO.sub.2, include an alkali earth metal element M as a fifth sub-component by 0.1 mol to 5.0 mol when converted into MCO.sub.3, on a presumption that an amount of the ceramic is 100 mol, wherein a ratio Si/V is 30 or less.

A method for the joining of ceramic pieces with a hermetically sealed joint comprising brazing a layer of joining material between the two pieces. The wetting and flow of the joining material is controlled by the selection of the joining material, the joining temperature, the joining atmosphere, and other factors. The ceramic pieces may be on a non-diffusable type, such as aluminum nitride, alumina, beryllium oxide, and zirconia, and the pieces may be brazed with an aluminum alloy under controlled atmosphere. The joint material is adapted to later withstand both the environments within a process chamber during substrate processing, and the oxygenated atmosphere which may be seen within the shaft of a heater or electrostatic chuck.

The invention relates to multi-layer oxide ceramic bodies and in particular to presintered multi-layer oxide ceramic blanks and oxide ceramic green bodies suitable for dental applications. These bodies can be thermally densified by further sintering without distortion and are thus particularly suitable for the manufacture of dental restorations. The invention also relates to a process for the manufacture of such multi-layer oxide ceramic bodies as well as to a process for the manufacture of dental restorations using the multi-layer oxide ceramic bodies.

A method for the joining of ceramic pieces with a hermetically sealed joint comprising brazing a continuous layer of joining material between the two pieces. The wetting and flow of the joining material is controlled by the selection of the joining material, the joining temperature, the time at temperature, the joining atmosphere, and other factors. The ceramic pieces may be aluminum nitride and the pieces may be brazed with an aluminum alloy under controlled atmosphere. The joint material is adapted to later withstand both the environments within a process chamber during substrate processing, and the oxygenated atmosphere which may be seen within the shaft of a heater or electrostatic chuck.

A composite includes a component and a glass or glass ceramic material. The component has a first coefficient of expansion .sub.1 and the glass or the glass ceramic material has a second coefficient of expansion .sub.2. The glass or the glass ceramic material has a surface with a thickness and thickness differences (TTV) within the surface, and thickness fluctuations (LTV). The composite has a residual stress in the glass or the glass ceramic material (WARP), and a geometric and material-physical degree of compatibility KG4.

A power-module substrate unit having at least one power-module substrate including one ceramic substrate, a circuit layer formed on one surface of the ceramic substrate, and a metal layer formed on another surface of the ceramic substrate, and a heat sink on which the metal layer of the power-module substrate is bonded, in which the metal layer is made of an aluminum plate having purity of 99.99 mass % or higher; the heat sink is made of an aluminum plate having purity of 99.90 mass % or lower; and the circuit layer has a stacking structure of a first layer made of an aluminum plate having the purity of 99.99 mass % or higher and being bonded to the ceramic substrate and a second layer made of the aluminum plate having the purity lower than 99.90 mass % and being bonded on a surface of the first layer.

A method for producing a dielectric ceramic includes: shaping mixed powdery particles including a cordierite material (2MgO.2Al.sub.2O.sub.3.5SiO.sub.2) and a low-temperature-sintering material including Al, Si and Sr, the Si being partially vitrified; and firing the resultant shaped body. The method includes the step of wet-pulverizing the low-temperature-sintering material together with at least the cordierite material to prepare mixed powder particles having a median diameter D50 less than 1 m; and, in a process until a time of the preparation of the mixed powder particles, the low-temperature-sintering material undergoes no step of wet-pulverizing only the low-temperature-sintering material, and drying the resultant pulverized material.

A zirconia sintered body is provided in which the strength between layers of powders is improved. A flexural strength of a test sample of the zirconia sintered body, measured pursuant to JISR1601, is not less than 1000 MPa. The test sample is formed by preparing a plurality of zirconia powders, each containing zirconia and preferably yttria as a stabilizer that suppresses phase transition of zirconia, the zirconia powders differing in a composition, layering the zirconia powders to form a zirconia composition, and sintering the zirconia composition to form a zirconia sintered body. The flexural strength is measured such that a load point is positioned at a boundary of the zirconia powders, the boundary traversing the test sample of the sintered body along a direction of load application.