A wafer boat according to the present disclosure includes a plurality of support columns, each having a pillar shape and comprising a plurality of grooves configured to have a wafer placed thereon, and support plates configured to support both end portions of the plurality of support columns, respectively. Each of the plurality of support columns are formed of a ceramic containing aluminum oxide or silicon carbide as a main constituent, and an outer side surface of the plurality of support columns is a ground surface and/or a polished surface.

An yttrium oxide-based sintered body contains yttrium oxide as a main constituent and 0.1 wt % or more and 5.0 wt % or less of zirconium on a ZrO.sub.2 basis. Such an yttrium oxide-based sintered body made with yttrium oxide and a certain amount of zirconium oxide therein is highly resistant to corrosive chemicals while maintaining superior resistance to plasma and corrosive gases.

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 metering device (10) for withdrawing and dispensing a melt consisting of or containing an oxide fibre reinforced oxide ceramic composite material.

A piezoelectric composition including manganese and a complex oxide having a perovskite structure represented by a general formula ABO.sub.3, wherein an A site element in the ABO.sub.3 is potassium or potassium and sodium, a B site element in the ABO.sub.3 is niobium, a concentration distribution of the manganese has a variation, and the variation shows a CV value of 35% or more and 440% or less.

A three-dimensional shaped object producing method is provided that includes: forming a layer from secondary particles (51) including a binder resin and primary particles containing at least a ceramic material; and applying a liquid that dissolves the binder resin on the formed layer. The liquid contains a solvent having a boiling point of 100° C. or higher and 210° C. or lower, a relative energy difference (RED) between the binder resin and the solvent is 1.0 or less, and the secondary particles (51) have a loose bulk density of 25% or higher and 55% or lower.

A method of fabricating a brake component made from a ceramic matrix composite is disclosed. In various embodiments, the method includes infiltrating a carbon fabric with a slurry containing a ceramic powder and a sintering aid; laying up the carbon fabric in a desired geometry to form a raw component; warm pressing the raw component to form a green component; and sintering the green component via a spark plasma sintering process to form a sintered component.

Provided is a piezoelectric ceramics including crystal grains each including: a first region that is formed of a perovskite-type metal oxide having a crystal structure in which a central element of a unit cell is located at an asymmetrical position; and a second region that is formed of a perovskite-type metal oxide having a crystal structure in which a central element of a unit cell is located at a symmetrical position, and that is present inside the first region, wherein a ratio of a cross-sectional area of the second region to a cross-sectional area of the piezoelectric ceramics is 0.1% or less.

A temperature-stable modified NiO—Ta.sub.2O.sub.5-based microwave dielectric ceramic material and a preparation method thereof are provided. Using ion doping modification to form solid solution structure is an important measure to adjust microwave dielectric properties, especially the temperature stability. Based on formation rules of the solid solution, ion replacement methods are designed including Ni.sup.2+ ions are replaced by Cu.sup.2+ ions, and (Ni.sub.1/3Ta.sub.2/3).sup.4+ composite ions are replaced by [(Al.sub.1/2Nb.sub.1/2).sub.ySn.sub.1-y].sup.4+ composite ions, which considers that cations with similar ionic radii to Ni.sup.2+ and Ta.sup.5+ ions can be introduced into the NiTa.sub.2O.sub.6 ceramic for doping under the same coordination environment (coordination number=6), and therefore a ceramic material with the NiTa.sub.2O.sub.6 solid solution structure can be obtained. The microwave dielectric ceramic material with excellent temperature stability and low loss is finally prepared by adjusting molar contents of each of doped ions, and its microwave dielectric properties are excellent.

A piezoelectric material including a perovskite-type metal oxide represented by the following general formula (1); Bi; and Mn, wherein the content of Bi is 0.1-0.5 mol % with respect to 1 mol of the metal oxide, the content of Mn is 0.3-1.5 mol % with respect to 1 mol of the metal oxide, and the piezoelectric material satisfies (L.sub.4−L.sub.5)/L.sub.5≧0.05 and (L.sub.8−L.sub.9)/L.sub.9≧0.05 when the lengths of twelve Bi—O bonds with Bi that is located at a 12-fold site with respect to O in a perovskite-type unit cell as a starting point are taken to be L.sub.1 to L.sub.12 in length order:

(Ba.sub.1-xM1.sub.x)(Ti.sub.1-yM2.sub.y)O.sub.3  (1)

wherein 0≦x≦0.2, 0≦y≦0.1, and M1 and M2 are mutually different metal elements which have a total valence of +6 and are selected from other elements than Ba, Ti, Bi and Mn.