To provide a dental zirconia blank which has high permeability, can reproduce a color tone close to a natural tooth and a strength to be able to tolerate in oral cavity. Furthermore, to provide a dental zirconia blank from which a prosthesis device of 4 or more units having high strength can be prepared. To provide a dental zirconia blank having a plurality of layers, comprising; a first layer consisting of a high permeability ceramic containing 91.6 to 96.5 mol % of zirconium oxide and 3.5 to 8.4 mol % of yttrium oxide, and a second layer consisting of a low permeability ceramic containing 95.6 to 98.5 mol % of zirconium oxide and 1.5 to 4.4 mol % of yttrium oxide, wherein a content rate of yttrium oxide in the low permeability ceramic is lower than a content rate of yttrium oxide in the high permeability ceramic by 0.5 to 5.4 mol %, and the first layer is positioned at one end of the plurality of layers in a layering direction.

Aluminum nitride crystal particles, aluminum nitride powders containing the same, production processes for both of them, an organic polymer composition comprising the aluminum nitride crystal particles and a sintered body. Each of the aluminum nitride crystal particles has a flat octahedral shape in a direction where hexagonal faces are opposed to each other, which is composed of two opposed hexagonal faces and 6 rectangular faces, in which the average distance D between two opposed corners of each of the hexagonal faces is 3 to 110 m, the length L of the short side of each of the rectangular faces is 2 to 45 m, and L/D is 0.05 to 0.8; each of the hexagonal faces and each of the rectangular faces cross each other to form a curve without forming a single ridge; and the true destiny is 3.20 to 3.26 g/cm.sup.3.

A method for producing a ceramic complex includes: preparing a raw material mixture that contains 5% by mass or more and 40% by mass or less of first rare earth aluminate fluorescent material particles containing an activating element and a first rare earth element different from the activating element, 0.1% by mass or more and 32% by mass or less of oxide particles containing a second rare earth element, and the balance of aluminum oxide particles, relative to 100% by mass of the total amount of the first rare earth aluminate fluorescent material particles, the oxide particles, and the aluminum oxide particles; preparing a molded body of the raw material mixture; and obtaining a sintered body by calcining the molded body in a temperature range of 1,550 C. or higher and 1,800 C. or lower.

Disclosed are a pseudo-ternary thermoelectric material, a method of manufacturing the pseudo-ternary thermoelectric material, a thermoelectric element, and a thermoelectric module. The pseudo-ternary thermoelectric material includes bismuth (Bi), antimony (Sb), tellurium (Te), and selenium (Se), and a composition ratio thereof is Bi.sub.xSb.sub.2-xTe.sub.3 in which 0.3x0.6 or (Bi.sub.2Te.sub.3).sub.1-x-y(Sb.sub.2Te.sub.3).sub.x(Sb.sub.2Se.sub.3).sub.y in which 0<x<1 and 0.001y0.05.

The invention relates to a refractory product, a batch composition for producing said product, a method for producing the product and the use of the refractory product.

Sintered product having a relative density of greater than 90%, with, to more than 80% of the volume thereof, a stack of flat ceramic platelets, the assembly of the platelets having a mean thickness of less than 3 m, having a width of greater than 50 mm, and including more than 20% of alumina, as a percentage on the basis of the weight of the product. The width of the product is the largest dimension measured in the plane in which the length of the product is measured, along a direction perpendicular to the direction of the length. The length of the product is the largest dimension thereof in a plane parallel to the general plane in which the platelets extend.

A super hard polycrystalline construction is disclosed as comprising a body of super hard material bonded to a substrate. The body of super hard material comprises an outer peripheral region formed of interbonded grains of super hard material extending peripherally around one or more inner regions, the outer peripheral region having a radial thickness proportional to the square of the ratio of the fracture toughness of the material forming said outer peripheral region to the transverse rupture strength of the material forming said outer peripheral region (I) where TRS is the transverse rupture strength and K.sub.IC is the fracture toughness.

Composite ceramic materials are disclosed herein which comprise two or more crystalline phases, wherein a first crystalline phase comprises a first refractory material having a first melting point, and a second crystalline phase comprises a second refractory material having a second melting point which is lower than the first melting point, and the second crystalline phase comprises large domain sizes of the second refractory material. Articles comprising such a composite ceramic material, such as honeycomb bodies, catalytic substrates, and particulate filters, are also disclosed herein, in addition to methods of manufacture thereof.

A selection method includes: obtaining or providing multilayer ceramic capacitors each having a multilayer structure in which each of a plurality of ceramic dielectric layers and each of a plurality of internal electrode layers are alternately stacked; measuring a ratio of (a current value at 10 V/?m when a direct voltage is applied to a plurality of ceramic dielectric layers at 125 degrees C.)/(a current value at 10 V/?m when a direct voltage is applied to the plurality of the ceramic dielectric layers at 85 degrees C.), with respect to each multilayer ceramic capacitor; determining whether the ratio is in a predetermined range; and selecting a multilayer ceramic capacitor or multilayer ceramic capacitors each having a ratio in the predetermined range as a desired multilayer ceramic capacitor.

It is difficult for a CrSi-based sintered body composed of chromium silicide (CrSi.sub.2) and silicon (Si) to have high strength. Provided is a CrSi-based sintered body including Cr (chromium) and silicon (Si), in which the crystal structure attributed by X-ray diffraction is composed of chromium silicide (CrSi.sub.2) and silicon (Si), a CrSi.sub.2 phase is present at 60 wt % or more in a bulk, a density of the sintered body is 95% or more, and an average grain size of the CrSi.sub.2 phase is 60 ?m or less.