A method of manufacturing a composite sintered body includes a step (Step S11) of molding mixed powder in which Al.sub.2O.sub.3, SiC, and MgO are mixed, into a green body having a predetermined shape and a step (Step S12) of generating a composite sintered body by sintering the green body. Then, in Step S11, the ratio of SiC to the mixed powder is not lower than 4.0 weight percentage and not higher than 13.0 weight percentage. Further, the purity of Al.sub.2O.sub.3 in Step S11 is not lower than 99.9%. It is thereby possible to suppress the abnormal grain growth of Al.sub.2O.sub.3 and suitably manufacture a composite sintered body having high relative dielectric constant and withstand voltage, and low tan .

An alumina sintered body including an inner layer in which alumina crystal grains contained have an average aspect ratio of 1.0 to 2.0 and an outer layer which covers at least a part of the inner layer from outside and in which alumina crystal grains contained have an average aspect ratio of more than 2.0, the alumina sintered body being free from silicon except unavoidable impurities.

Fused tuckstone defining lower and upper surfaces. The lower surface includes a support surface to rest on metallic structure of a glass furnace, a tank surface intended to face an upper edge of a tank of the furnace, and a lower transition surface connecting the support and tank surfaces. The upper surface includes a superstructure surface to receive a side wall of a superstructure of the furnace and an upper transition surface connecting the superstructure and lower surfaces. At least a part of the lower transition surface has a crystal density of more than four times the crystal density at a depth of 4 centimeters below the lower transition surface, a crystal density being evaluated by the number of crystals having a surface area of more than 12 m.sup.2 per mm.sup.2 of surface after polishing, the crystal density at the depth being evaluated after cutting of the tuckstone.

An oxide sintered body containing indium, hafnium, tantalum, and oxygen as constituent elements, in which when indium, hafnium, and tantalum are designated as In, Hf, and Ta, respectively, the atomic ratio of Hf/(In+Hf+Ta) is equal to 0.002 to 0.030, and the atomic ratio of Ta/(In+Hf+Ta) is equal to 0.0002 to 0.013.

A coated cutting tool, comprising: a substrate made of a cubic boron nitride-containing sintered body; and a coating layer formed on the substrate, wherein the cubic boron nitride-containing sintered body includes 65 volume % or more and 85 volume % or less of cubic boron nitride, and 15 volume % or more and 35 volume % or less of a binder phase; the cubic boron nitride is in a form of particles, the particles having an average particle size from 1.5 m or more to 4.0 m or less; the coating layer includes a lower layer, and an upper layer formed on the lower layer; the lower layer contains particles each having a composition represented by (Ti.sub.1-xAl.sub.x)N; the lower layer has an average thickness from 0.1 m or more to 1.0 m or less; the particles forming the lower layer have an average particle size from 0.01 m or more to 0.05 m or less; the upper layer contains particles each having a composition represented by (Ti.sub.1-yAl.sub.y)(C.sub.1-zN.sub.z); and the upper layer has an average thickness from 1.0 m or more to 5.0 m or less.

Setter plates are fabricated from Li-stuffed garnet materials having the same, or substantially similar, compositions as a garnet Li-stuffed solid electrolyte. The Li-stuffed garnet setter plates, set forth herein, reduce the evaporation of Li during a sintering treatment step and/or reduce the loss of Li caused by diffusion out of the sintering electrolyte. Li-stuffed garnet setter plates, set forth herein, maintain compositional control over the solid electrolyte during sintering when, upon heating, lithium is prone to diffuse out of the solid electrolyte.

Described herein are a bonded ceramic and a manufacturing method therefor. The bonded ceramic includes: a first ceramic substrate; and a second ceramic substrate, wherein the first ceramic substrate and the second ceramic substrate are bonded to each other without an adhesive layer therebetween and include pores, each of which is formed along a bonded surface therebetween and has a size of 0.01 to 50 m.

A method for producing a rare earth aluminate sintered body includes: preparing a molded body by mixing a fluorescent material having a composition of a rare earth aluminate and a raw material mixture comprising an oxide containing at least one rare earth element Ln selected from the group consisting of Y, La, Lu, Gd, and Tb, an oxide containing Ce, an oxide containing Al, and optionally an oxide containing at least one element M.sup.1 selected from the group consisting of Ga and Sc; and calcining the molded body to obtain a sintered body.

A ceramic composite can include a first ceramic phase and a second ceramic phase. The first ceramic phase can include a silicon carbide. The second phase can include a boron carbide. In an embodiment, the silicon carbide in the first ceramic phase can have a grain size in a range of 0.8 to 200 microns. The first phase, the second phase, or both can further include a carbon. In another embodiment, at least one of the first ceramic phase and the second ceramic phase can have a median minimum width of at least 5 microns.

Described herein are a bonded ceramic having a channel through which a fluid can flow, and a method for manufacturing the same. The bonded ceramic includes: a first ceramic base material; and a second ceramic base material, wherein: the first ceramic base material and the second ceramic base material are bonded by adhesive layer-free bonding; a pattern is formed on either or both of the bonding surface of the first ceramic base material where the first ceramic base material comes in contact with the second ceramic base material and the bonding surface of the second ceramic base material where the second ceramic base material comes in contact with the first ceramic base material; and the bonded ceramic includes pores having a size of 0.01 m to 50 m and formed along the bonding surface between the first ceramic base material and the second ceramic base material.