Abstract: In an electrolyte sheet for a solid oxide fuel cell according to the present invention, the number of flaws on at least one of surfaces of the sheet detected by a fluorescent penetrant inspection is 30 points or less in each of sections obtained by dividing the sheet into the sections each measuring 30 mm or less on a side. A unit cell for a solid oxide fuel cell according to the present invention comprises a fuel electrode, an air electrode, and the electrolyte sheet for a solid oxide fuel cell according to the present invention, which is disposed between the fuel electrode and the air electrode. A solid oxide fuel cell of the present invention includes the unit cell for a solid oxide fuel cell according to the present invention.

Abstract: The objective of one or more embodiments of the present invention is to provide a zirconia electrolyte which has high strength and which is suitable for a solid electrolyte layer of a solid oxide fuel cell, and a method for producing a zirconia electrolyte having high strength. The zirconia electrolyte according to one or more embodiments of the present invention is characterized in essentially consisting of zirconia stabilized by one or a plurality of oxides of rare earth selected from the group of scandium, yttrium, cerium, gadolinium and ytterbium, wherein a standard deviation of pore numbers in 10 or more regions having an area of 50 ?m2 and not overlapping with each other on a fracture surface is 2.5 or more.

Abstract: The objective of one or more embodiments of the present invention is to provide a zirconia electrolyte which has high strength and which is suitable for a solid electrolyte layer of a solid oxide fuel cell, and a method for producing a zirconia electrolyte having high strength. The zirconia electrolyte according to one or more embodiments of the present invention is characterized in essentially consisting of zirconia stabilized by one or a plurality of oxides of rare earth selected from the group of scandium, yttrium, cerium, gadolinium and ytterbium, wherein a standard deviation of pore numbers in 10 or more regions having an area of 50 ?m2 and not overlapping with each other on a fracture surface is 2.5 or more.

Abstract: In at least one of principal surfaces of the electrolyte sheet for a solid oxide fuel cell of the present invention, (1) a burr height [?H (0-3)] in a first zone is 100 ?m or less, as measured by irradiating the principal surface of the sheet with a laser beam at a pitch of 0.01 mm using a laser optical three-dimensional shape measurement device, the first zone being a zone extending between a peripheral edge of the sheet and a position 3 mm inside the peripheral edge, and (2) a ratio [?H (0.61-3)/?H (0-0.6)] of a burr height [?H (0.61-3)] in a third zone to a burr height [?H (0-0.6)] in a second zone is 0.5 or more and 2.0 or less, as calculated from the burr heights measured by irradiating the principal surface of the sheet with a laser beam at a pitch of 0.01 mm using the laser optical three-dimensional shape measurement device, the second zone being a zone extending between the peripheral edge of the sheet and a position 0.

Abstract: The present invention relates to a method of producing a scandia-stabilized zirconia sheet. The method includes the steps of: (1) pulverizing a scandia-stabilized zirconia sintered body to obtain a sintered scandia-stabilized zirconia powder having an average particle diameter (De), determined by a transmission electron microscope, in the range of 0.3-1.5 ?m, and an average particle diameter (Dr), determined by a laser scattering method, in the range of 0.3-3.0 ?m, where a ratio of Dr/De is at least 1.0-2.5; (2) preparing a slurry containing the sintered scandia-stabilized zirconia powder and an unsintered zirconia powder, where a percentage of the sintered scandia-stabilized zirconia powder to a sum of the sintered scandia-stabilized zirconia powder and the unsintered zirconia powder in the slurry is at least 2 mass % and at most 40 mass %; (3) molding the slurry into a green sheet; and (4) sintering the green sheet.

Abstract: The electrolyte sheet for solid oxide fuel cell of the present invention has different surface roughnesses between the peripheral region and the region other than the peripheral region at least on one side. The surface roughness Ra(b) in the peripheral region is at least 0.05 ?m and less than 0.3 ?m. The surface roughness Ra(i) in the region other than the peripheral region is at least 0.2 ?m and at most 1.2 ?m. And, the ratio of Ra(i) to Ra(b) (Ra(i)/Ra(b)) is more than 1 and at most 4. Here, the surface roughness Ra(b) and the surface roughness Ra(i) are arithmetic mean roughness values and determined by an optical and laser-based non-contact three-dimensional profile measuring device in accordance with a German standard ‘DIN-4768’.

Abstract: In at least one of principal surfaces of the electrolyte sheet for a solid oxide fuel cell of the present invention, (1) a burr height [?H (0-3)] in a first zone is 100 ?m or less, as measured by irradiating the principal surface of the sheet with a laser beam at a pitch of 0.01 mm using a laser optical three-dimensional shape measurement device, the first zone being a zone extending between a peripheral edge of the sheet and a position 3 mm inside the peripheral edge, and (2) a ratio [?H (0.61-3)/?H (0-0.6)] of a burr height [?H (0.61-3)] in a third zone to a burr height [?H (0-0.6)] in a second zone is 0.5 or more and 2.0 or less, as calculated from the burr heights measured by irradiating the principal surface of the sheet with a laser beam at a pitch of 0.01 mm using the laser optical three-dimensional shape measurement device, the second zone being a zone extending between the peripheral edge of the sheet and a position 0.

Abstract: An electrolyte sheet for solid oxide fuel batteries with mechanical strength characteristics is proposed. These characteristics may include a high and stable average value of strength, Weibull coefficient, and a high adhesion to an electrode formed on a surface thereof and hence inhibits the electrode from interfacial separation from the electrolyte sheet. The electrolyte sheet for solid oxide fuel batteries is characterized by having a plurality of concaves and/or convexes on at least one surface thereof, the concaves and convexes having base faces which are circular or elliptic or are a rounded polygon in which the vertexes have a curved shape with a curvature radius of 0.1 ?m or larger and/or the concaves and convexes having a three-dimensional shape which is semispherical or semiellipsoidal or is a polyhedron in which the vertexes and the edges have a curved cross-sectional shape having a curvature radius of 0.1 ?m or larger.

Abstract: In an electrolyte sheet for a solid oxide fuel cell according to the present invention, the number of flaws on at least one of surfaces of the sheet detected by a fluorescent penetrant inspection is 30 points or less in each of sections obtained by dividing the sheet into the sections each measuring 30 mm or less on a side. A unit cell for a solid oxide fuel cell according to the present invention comprises a fuel electrode, an air electrode, and the electrolyte sheet for a solid oxide fuel cell according to the present invention, which is disposed between the fuel electrode and the air electrode. A solid oxide fuel cell of the present invention includes the unit cell for a solid oxide fuel cell according to the present invention.

Abstract: The electrolyte sheet for solid oxide fuel cell of the present invention has different surface roughnesses between the peripheral region and the region other than the peripheral region at least on one side. The surface roughness Ra(b) in the peripheral region is at least 0.05 ?m and less than 0.3 ?m. The surface roughness Ra(i) in the region other than the peripheral region is at least 0.2 ?m and at most 1.2 ?m. And, the ratio of Ra(i) to Ra(b) (Ra(i)/Ra(b)) is more than 1 and at most 4. Here, the surface roughness Ra(b) and the surface roughness Ra(i) are arithmetic mean roughness values and determined by an optical and laser-based non-contact three-dimensional profile measuring device in accordance with a German standard ‘DIN-4768’.

Abstract: The process for production of a scandia-stabilized zirconia sheet according to the present invention is characterized in comprising the steps of pulverizing a scandia-stabilized zirconia sintered body to obtain a scandia-stabilized zirconia sintered powder having an average particle diameter (De) determined using a transmission electron microscope of more than 0.3 ?m and not more than 1.5 ?m, and an average particle diameter (Dr) determined by a laser scattering method of more than 0.3 ?m and not more than 3.0 ?m, and a ratio (Dr/De) of the average particle diameter determined by the laser scattering method to the average particle diameter determined using the transmission electron microscope of not less than 1.0 and not more than 2.

Abstract: An electrolyte sheet for solid oxide fuel batteries with mechanical strength characteristics is proposed. These characteristics may include a high and stable average value of strength, Weibull coefficient, and a high adhesion to an electrode formed on a surface thereof and hence inhibits the electrode from interfacial separation from the electrolyte sheet. The electrolyte sheet for solid oxide fuel batteries is characterized by having a plurality of concaves and/or convexes on at least one surface thereof, the concaves and convexes having base faces which are circular or elliptic or are a rounded polygon in which the vertexes have a curved shape with a curvature radius of 0.1 ?m or larger and/or the concaves and convexes having a three-dimensional shape which is semispherical or semiellipsoidal or is a polyhedron in which the vertexes and the edges have a curved cross-sectional shape having a curvature radius of 0.1 ?m or larger.

Abstract: The present invention relates to a ceramic sheet having uniform quality over its entire surface with a decreased number of detects such as foreign matters and flaws. When the ceramic sheet was divided into sections of 30 mm square or smaller, each divided section has 5 or less defects detected based on an image obtained with a charge coupled device (CCD) camera. The present invention also relates to a method for producing the ceramic sheet. In this method, a green sheet or a calcined sheet mainly including spherical ceramic particles having an average particle diameter of 0.1 to less than 5 ?m was used as a spacer. By using this spacer, the green sheet for ceramic sheet slides smoothly on the spacer surface when it shrinks in baking, and the friction resistance between the green sheet for ceramic sheet and the spacer is lowered. In this manner, the method of the present invention can mass-produce the above-described high quality ceramic sheets.

Abstract: The present invention provides electrolyte sheets for solid oxide fuel cells, the electrolyte sheets being able to improve their adhesion to electrode films formed on both surfaces thereof and being also able to improve electric power generation characteristics of fuel cells by an increase in their electrode reaction areas. There is disclosed an electrolyte sheet for solid oxide fuel cells including a sintered sheet, wherein surface roughness of the sheet as measured by an optical and laser-based non-contact three-dimensional profile measuring system is 2.0 to 20 ?m in Rz and 0.20 to 3.0 ?m in Ra, and wherein a ratio of Rz of one surface (having a greater Rz and a greater Ra) to Rz of the other surface having a smaller Rz and a smaller Ra is in a range of 1.0 to 3.0, and a ratio of Ra of one surface (having a greater Rz and a greater Ra) to Ra of the other surface having a smaller Rz and a smaller Ra is in a range of 1.0 to 3.

Abstract: This invention provides an electrolyte sheet for solid oxide fuel cells, characterized in: being formed by a doctor blade method or an extrusion molding method; being a scandia partially stabilized zirconia sheet, wherein 4 mol % to 6 mol % scandia is doped in a solid zirconia; a crystal structure thereof has a polycrystalline structure having a main body of tetragonal and including monoclinic phase, wherein a ratio of monoclinic phase (M), calculated by below described formula (1) from a diffraction peak intensity using X-ray diffraction, is 1% to 80%; and a Weibull modulus (m) thereof is not less than 10: a ratio of monoclinic phase(M:%)=[{monoclinic(1,1,1)+monoclinic(?1,1,1)}/{tetragonal and cubic(1,1,1)+monoclinic(1,1,1)+monoclinic(?1,1,1)}]×100??(1).

Abstract: The method of the present invention for producing a solid electrolyte sheet for a solid oxide fuel cells is characterized in comprising steps of obtaining a large-sized thin zirconia green sheet by molding and drying a slurry containing zirconia particles, a binder, a plasticizer and a dispersion medium; pressing the zirconia green sheet in the thickness direction with a pressure of not less than 10 MPa and not more than 40 MPa; firing the pressed zirconia green sheet at 1200 to 1500° C.; and controlling a time period when a temperature is within the range of from 500° C. to 200° C. to not less than 100 minutes and not more than 400 minutes when cooling the sheet after firing.

Abstract: Disclosed are a material for forming a fuel electrode for solid oxide fuel cell, and a fuel electrode formed using the material. The material enables to obtain a fuel electrode which has good gas permeability while being excellent in electrochemical reactivity, conductivity and durability of such characteristics. In addition, such a fuel electrode does not suffer from damage or destruction due to thermal stress between itself and another component.

Abstract: A single cell for SOFC operating at low temperatures is provided, including a first solid electrolyte with oxide ion conductivity at 800° C. of 0.015 S/cm or more and bending strength of 600 MPa or more, a fuel electrode and bonded to one side of the first electrolyte, comprised of a cermet of a catalyst and a second solid electrolyte with a conductivity of 0.08 S/cm or more, and an air electrode bonded to the other side of the first electrolyte comprised of a compound of first perovskite type oxide with a third solid electrolyte. The electrodes are coated with fuel and air electrode contact layers, respectively.

Abstract: Disclosed is an electrode support substrate for a fuel cell which is even, gives a small fluctuation in gas permeability, and is capable of carrying out printing of an anodic electrode with high adhesiveness, and which comprises a ceramic sheet having a porosity of 20 to 50%, a thickness of 0.2 to 3 mm and a surface area of 50 cm2 or more wherein the variation coefficient of measured values of the gas permeable amounts of areas measured by the method according to JIS K 6400 ranges from 5 to 20% and further the surface roughness measured with a laser optical manner three-dimensional shape measuring device may be 1.0 to 40 ?m as the maximum roughness depth (Rmax) thereof.

Abstract: Disclosed is an electrode support substrate for a fuel cell which is even, gives a small fluctuation in gas permeability, and is capable of carrying out printing of an anodic electrode with high adhesiveness, and which comprises a ceramic sheet having a porosity of 20 to 50%, a thickness of 0.2 to 3 mm and a surface area of 50 cm2 or more wherein the variation coefficient of measured values of the gas permeable amounts of areas measured by the method according to JIS K 6400 ranges from 5 to 20% and further the surface roughness measured with a laser optical manner three-dimensional shape measuring device may be 1.0 to 40 ?m as the maximum roughness depth (Rmax) thereof.