An optical wavelength conversion member and a light-emitting device including the optical wavelength conversion member. The light-emitting device (1) includes a container (3), a light-emitting element (5), and an optical wavelength conversion member (9). The optical wavelength conversion member (9) is composed of a polycrystalline ceramic sintered body containing, as main components, Al.sub.2O.sub.3 crystal grains and crystal grains of a component represented by formula A.sub.3B.sub.5O.sub.12:Ce. Specifically, A and B of the A.sub.3B.sub.5O.sub.12 individually represent at least one element selected from the following element groups: A: Sc, Y, and lanthanoids (except for Ce), and B: Al and Ga; the at least one element selected from the element groups is present in each crystal grain and the crystal grain boundary of the ceramic sintered body; and the element concentration of the crystal grain boundary is higher than the element concentration of the crystal grain.

A method for producing an optical wavelength conversion member (9) composed of a sintered body containing, as main components, Al.sub.2O.sub.3 and a component represented by formula A.sub.3B.sub.5O.sub.12:Ce; an optical wavelength conversion member; an optical wavelength conversion component including the optical wavelength conversion member; and a light-emitting device including the optical wavelength conversion member or the optical wavelength conversion component. The production method of the sintered body includes firing in a firing atmosphere having a pressure of 10.sup.4 Pa or more and an oxygen concentration of 0.8 vol. % or more and less than 25 vol. %.

The invention relates to a ceramic material (14) for generating light when irradiated with radiation, wherein the ceramic material comprises a stack of layers (15, 16) having different compositions and/or different dopings. The ceramic material may be used in a spectral computed tomography (CT) detector, in order to spectrally detect x-rays, or it may be used as a ceramic gain medium of a laser such that temperature gradients and corresponding thermo-mechanical stresses within the gain medium can be reduced.

The invention relates to a porous multi-layered coloured zirconia dental mill blank comprising a bottom layer B having the composition COMP-B which comprises ceramic components CER-COMP-B, colouring components COL-COMP-B and stabilizing components STAB-COMP-B, a top layer E having the composition COMP-E which comprises ceramic components CER-COMP-E, colouring components COL-COMP-E stabilizing components STAB-COMP-E, at least one intermediate layer Ex having the composition COMP-E of top layer E, at least one intermediate layer Bx having the composition COMP-B of bottom layer B, x being an integer and indicating the number of intermediate layers, wherein the layers with compositions COMP-B and COMP-E are arranged in alternating order, and wherein the thickness of the individual layers B, Bx is decreasing from bottom to top and the thickness of the individual layers E, Ex is decreasing from top to bottom. The dental mill blank can be used for producing dental articles.

Provided is a MgAl.sub.2O.sub.4 sintered body, which includes a relative density of the MgAl.sub.2.sub.4 sintered body being 90% or higher, and an L* value in a L*a*b* color system being 90 or more. A method of producing a MgAl.sub.2O.sub.4 sintered body is characterized by that a MgAl.sub.2O.sub.4 powder is hot pressed at 1150 to 1300 C., and is thereafter subjected to atmospheric sintering at 1350 C. or higher. Embodiments of the present invention address the issue of providing a high density and white MgAl.sub.2O.sub.4 sintered body and a sputtering target using the sintered body, and a method of producing a MgAl.sub.2O.sub.4 sintered body.

A chromaticity of zinc oxide is measured. The durability of a zinc oxide varistor is evaluated based on the chromaticity. This provides a varistor with a high durability stably.

An optical wavelength conversion member (9) provided with a ceramic plate (11) which is configured from a polycrystalline body that is mainly composed of Al.sub.2O.sub.3 and a component represented by A.sub.3B.sub.5O.sub.12:Ce; and each of A and B in A.sub.3B.sub.5O.sub.12 represents at least one element selected from the element groups described below. In addition, a dielectric multilayer film (13) which transmits a specific wavelength and reflects another specific wavelength is formed on a light incident surface (11a) of the ceramic plate (11). The ceramic plate (11) has a porosity of 2% by volume or less, while having an average surface roughness (an arithmetic mean roughness Sa) of 0.5 m or less. A: Sc, Y and lanthanoids (excluding Ce) B: Al and Ga. Also disclosed is a light-emitting device including the optical wavelength conversion member.

A zirconia sintered body contains aluminum, cobalt, and manganese and a remaining portion consisting of yttria-containing zirconia. In an oxide exchange, aluminum content is 5.0 wt % or more and 30.0 wt % or less, cobalt content is 0.1 wt % or more and 2.0 wt % or less, and manganese content is 0.5 wt % or more and 7.0 wt % or less.

A dental zirconia system to produce translucent zirconia sintered bodies comprises at least two separate zirconia green bodies. At least one zirconia green body comprises zirconium oxide and a lower content of at least one other oxide summing to between 6.5 wt % to 20 wt % based on a total weight percent of the zirconia green body. At least another zirconia green body comprises zirconium oxide and a higher content of at least one other oxide summing to between 7.5 wt % to 20 wt % based on a total weight percent of the zirconia green body. The at least two zirconia green bodies each have at least some particles with a diameter of 100 nanometers to 1000 nanometers. The at least two zirconia green bodies have different amounts of the at least one other oxide with respect to one another.

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 1100 MPa. The test sample is formed by preparing a plurality of zirconia powders, each containing zirconia and 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.