Alcatel Alsthom Compagnie Generale D'electricite

Alcatel

Gec Alsthom Sa

Gerard Duperray

Peter Friedrich Herrmann

Denis Legat

Albert Leriche

Francoise Ducatel

Jean-Pierre Tavergnier

Erick Beghin

Fernand Grivon

Fernard Grivon

A powder in tube method of making an HTc superconductive multifilament strand having a silver-based matrix, in which method: prior to the monofilament step: a composite multilayer material is prepared comprising at least one silver-based sheet, and at least one layer of non-superconductive ceramic material that is permeable to oxygen; and during the monofilament step, a thickness of composite multilayer material is interposed between first and second thicknesses of silver-based material, thereby forming said first silver-based envelope.

Method of decoupling an HTc superconductive multifilament strand having

A process for texturing an HTc superconductor of the matrix type based on silver and the superconductor material (Bi.sub.1-x Pb.sub.x).sub.2 Sr.sub.2 Ca.sub.y Cu.sub.1+y O.sub.6+2y where x.epsilon.[0; 0,4] and y.epsilon.{0, 1, 2} includes the following steps carried out in succession: raising the temperature of the superconductor from room temperature to the melting point of the superconductor material, maintaining the temperature of the superconductor constant at the melting point of the superconductor material for a relatively short period, varying the temperature of the superconductor between the melting point of the superconductor material and its synthesis temperature, maintaining the temperature of the superconductor constant at the synthesis temperature of the superconductor material for a relatively long period and reducing the temperature of the superconductor from the synthesis temperature of the superconductor material to room temperature. The step of varying the temperature of the superconductor between the melting point of the superconductor material and its synthesis temperature comprises sudden cooling of the superconductor from the melting point of the superconductor material to an end of cooling temperature less than the synthesis temperature of the superconductor material, and raising the temperature of the superconductor from the end of cooling temperature to the synthesis temperature of the superconductor material.

Process for texturing an HTc superconductor and superconductor made by

A sheathed twisted superconductor with a high critical temperature is made from a billet obtained by assembling square cross-section single strands in a square cross-section metal tube. The multistrand obtained by drawing the billet through a roller die is twisted with a particular lay and rolled using rollers the diameter of which is much greater than the twist lay. The sheathed twisted superconductor obtained by this method is intended for variable current applications.

Method of manufacturing a sheathed twisted superconductor having a high

In a method for the manufacture of an encased high critical temperature superconducting wire by the 'powder in tube' method, prior to the introduction of a compressed rod of superconducting material into a silver tube, the rod is heat treated so that grains of unwanted phase are reabsorbed. The tube can be drawn more easily, and strands can be produced with a regular geometry and no defects. The wire is constituted by 15 .mu.m to 20 .mu.m thick filaments (30) with a form factor of more than 60.

Method of manufacturing an encased wire of high critical temperature

A process for obtaining precursors for high critical temperature superconductor ceramics by precipitating salts which are insoluble in water comprises the following stages: A starting solution of soluble salts is prepared in which the cations are in the stoichiometric proportions of the required superconductor phase. A first full precipitation is carried out of a first series of cations at a first value of pH. The first precipitates obtained is filtered out and washed and the filtrate is retained. The pH of the filtrate is changed to a second value and the residual cations are precipitated. The second precipitate is filtered. The first and second precipitates are homogenized. The product obtained is dried, calcined, and ground.

Process for obtaining precursors for high critical temperature

A method of making at least one low electrical resistance connection between a metal and a high T.sub.c superconducting ceramic part, said part being made from a ceramic powder which is placed in a mold, compressed, and sintered, wherein at least one volume of silver or gold powder corresponding to the shape of said connection and situated at the desired location is placed inside said mold in juxtaposition with said ceramic powder but without being mixed therewith, after which the compression and the sintering are performed under an atmosphere containing oxygen and at a temperature that is lower than the melting temperature of silver or gold.

Growing community of inventors

La Norville, France

Gerard Duperray