Abstract: A solid oxide fuel cell having an ion conductive solid electrolyte layer formed by a spraying method, wherein a thickness of the solid electrolyte layer is not less then 40 .mu.m and not more than 100 .mu.m, and a leakage amount of N.sub.2 gas of the solid electrolyte layer at room temperature is not more than 10.sup.-5 cc/g.second. A permeation coefficient of the solid electrolyte layer is preferably not more than 10.sup.-7 cm.sup.4 /g.second at room temperature. The solid electrolyte layer includes at least one metal element selected from manganese, iron, cobalt, nickel, copper and zinc, in an average amount of not less than 1 atom % and not more than 15 atom % based on a sum of amounts of all metal elements contained in the solid electrolyte layer.

Abstract: An air electrode body for a solid oxide fuel cell, which is composed of a perovskite-type structure having a chemical composition of (La.sub.1-x A.sub.x).sub.1-y MnO.sub.3 wherein 0<x.ltoreq.0.5, 0<y.ltoreq.0.2, and A is at least one metal selected from strontium, calcium, manganese, barium, yttrium, cerium and ytterbium. The air electrode body has a porosity of 15 to 40% and an average pore diameter of 1-5 .mu.m. A process for producing the air electrode body, includes the steps of: mixing lanthanum or a lanthanum compound, manganese or a manganese compound, a metal A or a compound of the metal A wherein A is at least one kind of metals selected from the group of strontium, calcium, manganese, barium, yttrium, cerium and ytterbium; calcining the resulting mixture at a temperature from 1,300.degree. C. to 1600.degree. C. to synthesize (La.sub.1-x A.sub.x).sub.1-y MnO.sub.3 ; grinding the synthesized material to a powder having an average particle diameter of 3 to 15 .mu.

Abstract: A method for operating a power generator in which a solid oxide fuel cell is used as a power-generating element and an air electrode of the solid oxide fuel cell is composed of lanthanum manganite, the method involving the step of setting a heating rate and a cooling rate at least in a temperature range of 800.degree. C. to 900.degree. C. at not less than 3.degree. C./min. when the fuel cell is heated up to an operating temperature at the time of starting the power generator and when the fuel cell is cooled from the operating temperature at the time of stopping the power generator. Alternatively, the method involves the step of setting a partial pressure of oxygen, at least in a temperature range of 800.degree. C. to 900.degree. C., in an atmosphere to which the air electrode is exposed, to at not less than 10.sup.-15 arms but not more than 10.sup.

Abstract: A porous sintered body composed mainly of lanthanum manganite in which a part of lanthanum atoms at A-sites of the lanthanum manganite are substituted by atoms of a metal selected from the group consisting of alkaline earth metals and rare earth metals. The dimensional shrinkage amount of the porous sintered body in heat cycling between room temperature and 1,000.degree. C. is not more than 0.01% per one heat cycle.

Abstract: An electrically conductive ceramic film having a large size and surface area, a complicated configuration and a high electrical conductivity can be provided by the present melt spray method. The method includes melt spraying a raw material of an electrically conductive ceramic on a substrate to form a melt sprayed film, and heat treating the melt spray film to produce the electrically conductive ceramic film.

Abstract: A method for producing interconnectors for electrically connecting unit cells of a solid electrolyte type fuel cell. An interconnector material such as a perovskite complexed oxide is thermally sprayed onto the surface of an electrode of a solid electrolyte type fuel cell by plasma thermal spraying process at a temperature of not lower than 1,250.degree. C. to form an interconnector, and heat treated to diminish the cracks and defects resulting from the plasma thermal spraying process.

Abstract: A method for producing an airtight and thin lanthanum chromite film having a splendid electrical conductivity including providing an air electrode film on a porous ceramic substrate, thermally spraying a raw material for thermally spraying lanthanum chromite on a surface of the air electrode film to form a thermally sprayed film, and heat treating the thermally sprayed film to form an interconnector. The raw material for thermally spraying lanthanum chromite may contain a doping metal or metals, such as, copper, and zinc, etc. The heat treating is effected preferably at a temperature of at least 1,250.degree. C.

Abstract: A solid electrolyte type fuel cell having decreased internal resistance and increased output and improved fuel utilization efficiency is provided. The fuel cell includes an air electrode substrate made of a perovskite series complexed oxide having the following composition of a formula (La.sub.1-y A.sub.y)MO.sub.3, wherein A is at least one element selected from alkaline earth metals, M is manganese or cobalt, and y is 0.ltoreq.y.ltoreq.0.4, a zirconia solid electrolyte film containing manganese or cobalt solid soluted at at least the neighborhood of the interface thereof with the air electrode substrate, and a fuel electrode film formed on the solid electrolyte film at a surface opposite to the air electrode substrate. The fuel cell does not include a highly resistive layer made of a compound containing lanthanum and zirconium at the interface between the air electrode substrate and the solid electrolyte film. Methods for producing the fuel cell are also disclosed.

Abstract: A cell unit for use in a solid oxide fuel cell has a laminate structure including a cell element and a separator. The cell element includes a dense and planar solid electrolyte having a rectangular plane shape, and an air electrode film and a fuel electrode film provided on opposite surfaces of the flat solid electrolyte, respectively. The separator is made of a dense electron conductor. A plurality of oxidizing gas flow paths are defined between the separator and the air electrode, and the cell element has a rectangular planar shape and a ratio of a short side to a long side of the rectangular planar shape is not less than 2.

Abstract: A solid electrolyte film being formed on a substrate by plasma spraying. The solid electrolyte film has a solid electrolyte structure composed of cerium oxide or zirconium oxide stabilized or partially stabilized with an alkaline earth metal element and/or a rare earth element. The solid electrolyte film has a true porosity of not more than 5%. A solid oxide fuel cell is also disclosed, which involves such a solid electrolyte film being formed on the substrate by plasma spraying, an air electrode provided on one side of the solid electrolyte films and a fuel electrode provided on the other side of the solid electrolyte film. The solid electrolyte film is formed on the substrate by densifying a plasma sprayed solid electrolyte raw film by heating the film in a temperature range of 1,300.degree. to 1,700.degree. C. In the cell, the fuel electrode film or the air electrode is formed onto a surface of the solid electrolyte film.

Abstract: A fuel electrode for solid oxide fuel cells, which is to be provided on a surface of an ion-conductive solid electrolyte body, includes a skeleton for a porous fuel electrode, and a thin filmy tissue which is composed of the same material as the solid electrolyte body, and covers the fuel electrode skeleton. Gaps are present between the thin filmy tissue and the fuel electrode skeleton. The skeleton is made of a material containing at least nickel.