摘要:
A superconductor comprising a composite oxide of rare earth elements (RE), barium and copper, wherein RE2BaCuO5 phases (211 phases) are finely dispersed in a single crystal REBa2Cu3O7-x phase (123 phase) and the 123 phase is composed of a multiplicity of layers corresponding to the composition of the RE arranged in the order of the 123 phase forming temperature; and a process for producing the superconductor which comprises forming a layer from a powdery mixture of oxides of the RE, barium and copper and also layers from other powdery mixtures of oxides of RE, barium and copper corresponding to other compositions of RE having different 123 phase forming temperatures from that of the abovementioned composition of RE to give a multilayered structure wherein the multiplicity of the layers are laminated in the ascending or descending order of the 123 phase forming temperatures thereof, press forming the laminate into a precursor, placing the precursor on a support material in such a manner that the layer having the highest 123 phase forming temperature among them forms the outermost layer, bringing it into a semi-molten state by heating in a temperature range where solid and liquid are coexistent, and cooling it slowly in the 123 phase forming temperature range, optionally after seeding with seed crystals, to grow 123 phase crystals at a rate of 5 mm/hr or less.
摘要:
A superconductor that is free of Tl and may have a sharp transition from metallic to superconducting behaviour at temperatures up to about 80K at least is characterized by the formula (Pba(A)1-a)(SrbBa1-b)2(Cac(B)1-c)Cu2O7 in which at least half the (A) atoms are Hg and the remainder, if any, are selected from one or more of Zn, Cd, Tl, Sc, Mg, and Cu; (B) is selected from Y and the rare earth elements; a is from 0.3 to 0.7; b is from 0 to 1; and c is from 0.2 to 0.5 (all limits inclusive).
摘要:
The present invention relates to novel multi-layer composite solid state membranes which are capable of separating oxygen from oxygen-containing gaseous mixtures at elevated temperatures. The membranes comprise a multicomponent metallic oxide porous layer having an average pore radius of less than about 10 micrometers and a multicomponent metallic oxide dense layer having no connected through porosity wherein the porous and dense layers are contiguous and such layers conduct electrons and oxygen ions at operating temperatures.
摘要:
The invention is a process for recovering oxygen from an oxygen-containing gaseous mixture containing one or more components selected from water, carbon dioxide or a volatile hydrocarbon which process utilizes ion transport membranes comprising a multicomponent metallic oxide containing strontium, calcium or magnesium. The process utilizes a temperature regime which overcomes problems associated with degradation of strontium-, calcium- and magnesium-containing multicomponent oxides caused by carbon dioxide.
摘要:
On a mis au point un procédé de production d'oxydes métalliques mélangés uniformes, tels que des mélanges supraconducteurs comprenant Y1Ba2Cu3O7-x, dans lequel lesdits métaux sont précipités sous forme d'oxalates obtenus à partir de solutions des métaux sous forme de sels d'un acide carboxylique dans un alcool.
摘要:
Disclosed is a method of manufacturing an oxide superconductor containing at least an alkaline earth metal and copper. This method comprises the steps of heating a material substance containing elements constituting the oxide superconductor, in an atmosphere having an oxygen partial pressure of at most 50 Torr at a temperature ranging from 500°C to 1000°C, and then heating the material substance in an oxygen-containing atmosphere. Also disclosed herein is a method of manufacturing composite oxide powder which is the precursor of the oxide superconductor. This method comprises the steps of heating the material substance in an atmosphere having an oxygen partial pressure of at most 50 Torr at a temperature ranging from 500°C to 1000°C, and crushing the material substance into powder.