The present invention addresses the problem of providing a plasma spraying material with which it is possible to form an HAp film that has high hardness and is not susceptible to abrasion, even under conditions involving plasma spraying with low flame energy. In the present invention, an HAp powder having an average particle diameter (D.sub.50) of 15-40 μm and a pore volume of 0.01-0.30 cc/g at a pore diameter of 2000 nm or less as measured through mercury intrusion makes it possible to form an HAp film that has high hardness, is not susceptible to abrasion, and can be subjected to plasma spraying, even under conditions involving plasma spraying with low flame energy.

Provided is a composite sintered body for an electrostatic chuck, which is not easily broken even if it is exposed to high-power plasma. Further, provided are an electrostatic chuck device using such a composite sintered body for an electrostatic chuck and a method of manufacturing a composite sintered body for an electrostatic chuck. The composite sintered body for an electrostatic chuck is a composite sintered body including an insulating ceramic and silicon carbide, in which crystal grains of the silicon carbide are dispersed in at least one selected from the group consisting of a crystal grain boundary and a crystal grain of a main phase formed by sintering crystal grains of the insulating ceramic.

A preparation method and use of a green fluorescent transparent ceramic are disclosed. The preparation method includes: weighing, according to a stoichiometric ratio, elements present in Ca.sub.3-x-yCe.sub.xA.sub.ySc.sub.2-xB.sub.zSi.sub.3-mC.sub.mO.sub.12, in forms of oxides, carbonates or nitrates as raw materials; mixing the raw materials, annealing, melting at a high temperature, cooling and annealing at a low temperature; putting the glass into a high-temperature furnace, holding, raising the temperature, and performing crystallization and densification sintering; finally cutting, reducing and surface-polishing, where A is at least one from the group consisting of Lu, Y, Gd, La and Na; B is at least one from the group consisting of Zr, Hf and Mg; C is at least one from the group consisting of Al and P; x, y, z and m satisfy 0.001≤x≤0.06, 0≤y≤0.06, 0≤z≤0.06 and 0≤m≤0.3, respectively.

A ceramic composition is disclosed comprising an inorganic batch composition comprising a magnesia source, a silica source, an alumina source, a titania source, and at least one rare earth oxide wherein the rare earth oxide comprises a particle size distribution (D.sub.90) of less than 5 m and a median particle size (D.sub.50) of about 0.4 m. A ceramic article comprising a first crystalline phase comprised predominantly of a solid solution of aluminum titanate and magnesium dititanate, a second crystalline phase comprising cordierite, a third crystalline phase comprising mullite, and a rare earth oxide, and a method of making same are disclosed.

A preparation method and use of a green fluorescent transparent ceramic are disclosed. The preparation method includes: weighing, according to a stoichiometric ratio, elements present in Ca.sub.3-x-yCe.sub.xA.sub.ySc.sub.2-xB.sub.zSi.sub.3-mC.sub.mO.sub.12, in forms of oxides, carbonates or nitrates as raw materials; mixing the raw materials, annealing, melting at a high temperature, cooling and annealing at a low temperature; putting the glass into a high-temperature furnace, holding, raising the temperature, and performing crystallization and densification sintering; finally cutting, reducing and surface-polishing, where A is at least one from the group consisting of Lu, Y, Gd, La and Na; B is at least one from the group consisting of Zr, Hf and Mg; C is at least one from the group consisting of Al and P; x, y, z and m satisfy 0.001?x?0.06, 0?y?0.06, 0?z?0.06 and 0?m?0.3, respectively.

Provided is a composite sintered body for an electrostatic chuck, which is not easily broken even if it is exposed to high-power plasma. Further, provided are an electrostatic chuck device using such a composite sintered body for an electrostatic chuck and a method of manufacturing a composite sintered body for an electrostatic chuck. The composite sintered body for an electrostatic chuck is a composite sintered body including an insulating ceramic and silicon carbide, in which crystal grains of the silicon carbide are dispersed in at least one selected from the group consisting of a crystal grain boundary and a crystal grain of a main phase formed by sintering crystal grains of the insulating ceramic.

A sensor element for an exhaust gas sensor includes a ceramic base body whose surface includes at least one surface region that is electrically insulating, the sensor element including at least one flat guide structure, which is electrically conductive, along the surface region of the base body. The guide structure is partially embedded in the base body in a direction perpendicular to the surface.

An electromechanical transducer element includes a first electrode, a second electrode, and a piezoelectric material. The piezoelectric material is disposed between the first electrode and the second electrode and deformable with a voltage applied in accordance with a drive signal. The piezoelectric material is made of a composite oxide having a perovskite structure preferentially oriented in at least one of a (100) plane and a (001) plane. A drop in diffraction intensity is included in a rocking curve corresponding to at least one of a (200) plane and a (002) plane measured at a position of 2? where the diffraction intensity is largest at a peak of diffraction intensity corresponding to the (200) plane out of peaks of diffraction intensity measured by an X-ray diffraction ?-2? method.

An electromechanical transducer element includes a first electrode, a second electrode, and a piezoelectric material. The piezoelectric material is disposed between the first electrode and the second electrode and deformable with a voltage applied in accordance with a drive signal. The piezoelectric material is made of a composite oxide having a perovskite structure preferentially oriented in at least one of a (100) plane and a (001) plane. A drop in diffraction intensity is included in a rocking curve corresponding to at least one of a (200) plane and a (002) plane measured at a position of 2 where the diffraction intensity is largest at a peak of diffraction intensity corresponding to the (200) plane out of peaks of diffraction intensity measured by an X-ray diffraction 0-20 method.