A refractory object may include a zircon body that is intentionally doped with a dopant including an alkaline earth element and aluminum. The refractory object can have an improved creep deformation rate. In an embodiment, the refractory object can have a creep deformation rate of not greater than about 1.8 E-5 h.sup.−1 at a temperature of 1350° C. and a stress of 2 MPa. In another embodiment, the zircon body may include an amorphous phase including an alkaline earth metal element.

The present invention relates to a method for producing a metal-ceramic substrate. The method has the following steps: providing a stack containing a ceramic body, a metal foil, and a solder material in contact with the ceramic body and the metal foil, wherein the solder material has: a metal having a melting point of at least 700° C., a metal having a melting point of less than 700° C., and an active metal; and heating the stack, wherein at least one of the following conditions is satisfied: the high temperature heating duration is no more than 60 min; the peak temperature heating duration is no more than 30 min; the heating duration is no more than 60 min.

A composition comprises a zirconia powder, in which 55% or more thereof is monoclinic, and a stabilizer capable of suppressing phase transition of zirconia. An average particle diameter of zirconia particles and particles of the stabilizer is 0.06 μm to 0.17 μm. At least a portion of the stabilizer does not form a solid solution with zirconia.

A member for a plasma processing device of the present disclosure is a member for a plasma processing device made of ceramics and having a shape of a cylindrical body with a through hole in an axial direction. The ceramics is mainly composed of aluminum oxide, and has a plurality of crystal grains and a grain boundary phase that is present between the crystal grains. An inner peripheral surface of the cylindrical body has an arithmetic average roughness Ra of 1 μm or more and 3 μm or less, and an arithmetic height Rmax of 30 μm or more and 130 μm 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.

Disclosed herein is a sintered ceramic body comprising from 90% to 99.9% by volume of polycrystalline yttrium aluminum garnet (YAG) as measured using XRD and image processing methods and a volumetric porosity of from 0.1 to 4% as calculated from density measurements performed in accordance with ASTM B962-17. The sintered ceramic body may have a total purity of 99.99% and greater and a grain size of from 0.3 to 8 μm. A method of making the sintered ceramic body is also disclosed.

A method for producing a zirconia sintered body includes: heating a zirconia molded body or a zirconia pre-sintered body, the heating includes a temperature increasing step, and a rate of temperature increase in a temperature region from a temperature at which the zirconia starts to shrink to a temperature at which the zirconia finishes shrinking in the temperature increasing step is adjusted to enable the zirconia molded body or the zirconia pre-sintered body to shrink at substantially a constant rate during temperature increase in each of zones of when the temperature region is evenly divided into a plurality of zones of specific temperature ranges.

A dielectric composition includes dielectric particles, grain boundary phases, and segregations. The dielectric particles each include a perovskite compound represented by ABO.sub.3 as a main component. The grain boundary phases are located between the dielectric particles. The segregations exist in a part of the grain boundary phases and include at least Al, Si, and O. A molar ratio (Al/(Al+Si)) of an Al content to a total content of Al and Si in the segregations is 0.45 or more and 0.75 or less.

In a silicon nitride substrate including a silicon nitride sintered body including silicon nitride crystal grains and a grain boundary phase, a plate thickness of the silicon nitride substrate is 0.4 mm or les, and a percentage of a number of the silicon nitride crystal grains including dislocation defect portions inside the silicon nitride crystal grains in a 50 μm×50 μm observation region of any cross section or surface of the silicon nitride sintered body is not less than 0% and not more than 20%. Etching resistance can be increased when forming the circuit board.

Cordierite-forming batch mixtures including one or more non-oxide inorganic source materials or materials as pore-formers are provided. Non-oxide inorganic materials, such a non-oxide silicon material that includes at least one of silicon carbide, silicon, or silicon nitride, may be added to cordierite-forming batch mixtures as at least a partial replacement for conventional inorganic pore-formers. Non-oxide inorganic pore-formers may provide an increase in pore volume while having a reduced coefficient of thermal expansion impact as compared with conventional pore-formers. Cordierite-forming mixtures as disclosed herein may additionally include rare-earth catalysts and alkaline-earth materials that may enhance the pore-forming effect of non-oxide inorganic pore-formers without significant exothermic reactions or the production of emissions that may require additional processing treatments.