Abstract: A first method for manufacturing a solid oxide film having a highly densified solid oxide film having a small thickness and an improved electric conductivity; and a second method for manufacturing a solid oxide fuel cell in which a solid oxide film formed on an air electrode or a fuel electrode is manufactured by the first method. The solid oxide fuel cell according to the present invention is capable of generating a high power. The solid oxide film is formed on a substrate in such manner that a solid oxide material is sprayed on the substrate to form a sprayed solid oxide film thereon; Then a solution of metal compound including at least one metal selected from a group of manganese, iron, cobalt, nickel, copper and zinc is impregnated into the sprayed solid oxide film; and the sprayed solid oxide film is subjected to a heat treatment in order to increase an airtightness of the film. It may be possible to use a material for spraying, in which 1.about.

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 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.

Abstract: A sintered body of a ceramics material consisting essentially of a mixture of lanthanum chromite of the formula of LaCrO.sub.3 with an oxide of a specifically limited metal, or consisting essentially of lanthanum chromite, whose Cr is partly replaced by a specifically limited metal, has high mechanical strength and electroconductivity and is very useful as an interconnecting member of fuel cell. A mixture of lanthanum chromite, whose Cr is partly replaced by a specifically limited metal, with an oxide of a specifically limited metal is effective for obtaining a sintered body having high mechanical strength and electroconductivity in a high sinterability.

Abstract: A homogeneous Si.sub.3 N.sub.4 sintered body is produced having a proportion of a grain boundary crystalline phase to the whole grain boundary of 50% or less, maximum pore diameter of 10 .mu.m or less and a porosity of 0.5% or less. A process for manufacturing each an Si.sub.3 N.sub.4 sintered body is, in conventional processes wherein a starting material for Si.sub.3 N.sub.4 is mixed with a sintering aid, pulverized, granulated, then molded and subsequently fired, characterized in that a temperature lowering rate from a firing temperature to 1,000.degree. C. is made to be 30.degree. C./min. Another process of the invention is, in the above conventional process, characterized in that Si.sub.3 N.sub.4 containing at least 90% of .alpha.-Si.sub.3 N.sub.4 as a starting material and a sintering aid, both having an average grain diameter of 1 .mu.m or less, are used, the granulated powder is once forcedly dried and then, if required, water is added, before the molding and firing.

Abstract: A method of producing a composite ceramic structure, including: preparing a formed ceramic piece which constitutes a portion of the composite ceramic structure; preparing a rubber mold having a molding surface defining a remaining portion of the composite ceramic structure; positioning the rubber mold in contact with a joining part of the formed ceramic piece from which the remaining portion of the composite ceramic structure extends; covering an exposed surface of the formed ceramic piece, and at least an end of the rubber mold adjacent to the joining part of the formed ceramic piece, with an elastic member; filling the rubber mold with a mass of ceramic powder such that the mass of ceramic powder contacts the joining part of the formed ceramic piece, the mass of ceramic powder being substantially identical in composition with a ceramic material of which the formed ceramic piece is formed; applying a static hydraulic pressure to an assembly of the formed ceramic piece and the mass of ceramic powder in the ru

Abstract: Ceramic parts of complicated configurations with different thicknesses at different portions can be mass produced economically with high production yield and excellent quality using an injection molding process.

Abstract: A method of dynamically balancing an assembly of a metal jig and a ceramic rotor attached thereto, the ceramic rotor having a shaft portion, and the metal jig having at its one axial end a fixing hole, comprising the steps of: inserting the shaft portion of the ceramic rotor into the fixing hole of the metal jig, and thereby fixing the ceramic rotor to the metal jig to provide the assembly; and dynamically balancing the assembly by fixing at least one balancing piece in at least one of a plurality of balancing holes which are formed in the metal jig, the balancing holes being open in an outer surface of the metal jig. Also disclosed is a metal jig of a generally cylindrical shape for rotating a ceramic rotor in a dynamically balanced condition, having a fixing hole in its one axial end portion, in which a shaft portion of the ceramic rotor is inserted and fixed.

Abstract: A method of producing a composite ceramic structure, including: preparing a formed ceramic piece which constitutes a portion of the composite ceramic structure; preparing a rubber mold having a molding surface defining a remaining portion of the composite ceramic structure; positioning the rubber mold in contact with a joining part of the formed ceramic piece from which the remaining portion of the composite ceramic structure extends; covering an exposed surface of the formed ceramic piece, and at least an end of the rubber mold adjacent to the joining part of the formed ceramic piece, with an elastic member; filling the rubber mold with a mass of ceramic powder such that the mass of ceramic powder contacts the joining part of the formed ceramic piece, the mass of ceramic powder being substantially identical in composition with a ceramic material of which the formed ceramic piece is formed; applying a static hydraulic pressure to an assembly of the formed ceramic piece and the mass of ceramic powder in the ru