A sintered bead with the following crystal phases, in percentages by mass based on crystal phases: 25%zircon, or Z.sub.1, 94%; 4%stabilized zirconia+stabilized hafnia, or Z.sub.2, 61%; monoclinic zirconia+monoclinic hafnia, or Z.sub.350%; corundum57%; crystal phases other than Z.sub.1, Z.sub.2, Z.sub.3 and corundum<10%; the following chemical composition, in percentages by mass based on oxides: 33%ZrO.sub.2+HfO.sub.2, or Z.sub.483.4%; HfO.sub.22%; 10.6%SiO.sub.234.7%; Al.sub.2O.sub.350%; 0%Y.sub.2O.sub.3, or Z.sub.5; 0%CeO.sub.2, or Z.sub.6; 0.3%CeO.sub.2+Y.sub.2O.sub.319%, provided that (1) CeO.sub.2+3.76*Y.sub.2O.sub.30.128*Z, and (2) CeO.sub.2+1.3*Y.sub.2O.sub.30.318*Z, with Z=Z.sub.4+Z.sub.5+Z.sub.6(0.67*Z.sub.1*(Z.sub.4+Z.sub.5+Z.sub.6)/(0.67*Z.sub.1+Z.sub.2+Z.sub.3)); MgO5%; CaO2%; oxides other than ZrO.sub.2, HfO.sub.2, SiO.sub.2, Al.sub.2O.sub.3, MgO, CaO, CeO.sub.2 and Y.sub.2O.sub.3<5.0%.

There is provided an oxide sintered material containing indium, tungsten, and zinc, the oxide sintered material including: a first crystal phase that is a main component of the oxide sintered material and includes a bixbyite type crystal phase; and a second crystal phase having a content of the zinc higher than a content of the zinc in the first crystal phase, the second crystal phase including particles having an average major axis size of not less than 3 m and not more than 50 m and having an average aspect ratio of not less than 4 and not more than 50.

A method of producing polycrystalline Y.sub.3Ba.sub.5Cu.sub.8O.sub.y (Y-358) whereby powders of yttrium (III) oxide, a barium (II) salt, and copper (II) oxide are pelletized, calcined at 850 to 950 C. for 8 to 16 hours, ball milled under controlled conditions, pelletized again and sintered in an oxygen atmosphere at 900 to 1000 C. for up to 72 hours. The polycrystalline Y.sub.3Ba.sub.5Cu.sub.8O.sub.y thus produced is in the form of elongated crystals having an average length of 2 to 10 m and an average width of 1 to 2 m, and embedded with spherical nanoparticles of yttrium deficient Y.sub.3Ba.sub.5Cu.sub.8O.sub.y having an average diameter of 5 to 20 nm. The spherical nanoparticles are present as agglomerates having flower-like morphology with an average particles size of 30 to 60 nm. The ball milled polycrystalline Y.sub.3Ba.sub.5Cu.sub.8O.sub.y prepared under controlled conditions shows significant enhancement of superconducting and flux pinning properties.

A silicon nitride sintered body having improved wear resistance and a wear-resistant member using the silicon nitride sintered body are provided. A silicon nitride sintered body according to an embodiment includes silicon nitride crystal grains and a grain boundary phase. An average value of solid solution oxygen amounts of the silicon nitride crystal grains in a 20 m20 m region at any cross section is not less than 0.2 wt %. In a 50 m50 m region at any cross section, an average value of major diameters of the silicon nitride crystal grains is not less than 0.1 m and not more than 10 m, and an average value of aspect ratios of the silicon nitride crystal grains is not less than 1.5 and not more than 10.

Provided are: an oxide sintered material including an In.sub.2O.sub.3 crystal phase, a Zn.sub.4In.sub.2O.sub.7 crystal phase and a ZnWO.sub.4 crystal phase, wherein the roundness of crystal particles composed of the ZnWO.sub.4 crystal phase is 0.01 or more and less than 0.7; a method for producing the oxide sintered material; and a method for manufacturing a semiconductor device including an oxide semiconductor film that is formed by using the oxide sintered material as a sputter target.

It is an object to provide a cubic boron nitride polycrystalline material excellent in toughness. A cubic boron nitride polycrystalline material containing fine cubic boron nitride which is granular, has a maximum grain size not greater than 100 nm, and has an average grain size not greater than 70 nm and at least one of plate-shaped cubic boron nitride in a form of a plate having an average major radius not smaller than 50 nm and not greater than 10000 nm and coarse cubic boron nitride which is granular, has a minimum grain size exceeding 100 nm, and has an average grain size not greater than 1000 nm is provided.

A heat-dissipating member includes aluminum oxide ceramics that includes crystal particles of aluminum oxide. The aluminum oxide ceramics includes 98 mass % or higher of aluminum in terms of Al.sub.2O.sub.3 with respect to 100 mass % of all constituents. The crystal particles have an average equivalent circle diameter of 1.6 m or more and 2.4 m or less. An equivalent circle diameter cumulative distribution curve of the crystal particles has a first diameter at 10 cumulative percent and a second diameter at 90 cumulative percent that is different from the first diameter by 2.1 m or more and 4.2 m or less.

The present invention relates to a bismuth-based solid solution ceramic material, as well as a process for preparing the ceramic material and uses thereof, particularly in an actuator component employed, for example, in a droplet deposition apparatus. In particular, the present invention relates to a ceramic material having a general chemical formula (I): (I): x(Bi.sub.0.5Na.sub.0.5)TiO.sub.3-y(Bi.sub.0.5K.sub.0.5)TiO.sub.3-z.sub.1SrHfO.sub.3-z.sub.2SrZrO.sub.3, wherein x+y+Z.sub.1+Z.sub.2=1; y, (z.sub.1+z.sub.2)0; x0. In embodiments, the present invention also relates to a ceramic material having a general chemical formula (II): x(Bi0.5Na0.5)TiO3-y(Bi0.5K0.5)TiO3-y(Bi0.5K0.5)TiO3-ZiSrHfO3-z2SrZrO3, wherein x+y +z-i+z2=1; x, y, fa+z2)0; as well as a ceramic material of general formula (III): y(Bi.sub.0.5K.sub.0.5)TiO.sub.3-z.sub.1SrHfO.sub.3-z.sub.2SrZrO.sub.3, wherein y+z.sub.1,+z.sub.2=1; y, (z.sub.1+z.sub.2)0.

A method of producing polycrystalline Y.sub.3Ba.sub.5Cu.sub.8O.sub.y (Y-358) whereby powders of yttrium (III) oxide, a barium (II) salt, and copper (II) oxide are pelletized, calcined at 850 to 950? C. for 8 to 16 hours, ball milled under controlled conditions, pelletized again and sintered in an oxygen atmosphere at 900 to 1000? C. for up to 72 hours. The polycrystalline Y.sub.3Ba.sub.5Cu.sub.8O.sub.y thus produced is in the form of elongated crystals having an average length of 2 to 10 ?m and an average width of 1 to 2 ?m, and embedded with spherical nanoparticles of yttrium deficient Y.sub.3Ba.sub.5Cu.sub.8O.sub.y having an average diameter of 5 to 20 nm. The spherical nanoparticles are present as agglomerates having flower-like morphology with an average particles size of 30 to 60 nm. The ball milled polycrystalline Y.sub.3Ba.sub.5Cu.sub.8O.sub.y prepared under controlled conditions shows significant enhancement of superconducting and flux pinning properties.

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.