Abstract: The invention relates a powder in tube type method of making an HTc superconductive multifilament strand having a silver-based matrix, in which: a first envelope is filled with powder reagents for an HTc superconductor; the resulting billet is drawn down into a monofilament strand; said monofilament strand is cut up into lengths and a secondary envelope is filled with the resulting lengths, thereby making a multifilament billet which is drawn down into a multifilament strand; said multifilament strand is cut up into lengths and a new envelope is filled with the resulting lengths, thereby making a new multifilament billet which is drawn down into a new multifilament strand; and it is shaped and subjected to heat treatment; according to the invention, at least one face of the monofilament strand is electrically insulated; and during the first multifilament step the secondary envelope is filled with the resulting insulated lengths.

Abstract: The invention relates to a powder in tube type method of manufacturing an HTc superconductor multifilament conductor having a matrix of compatible silver alloy and in which, during preparation of the multifilament billet, the number of segments per layer is organized so that, in cross-section, the segment layers viewed as a whole have the general shape of a converging-diverging nozzle, the throat of the converging-diverging nozzle shape being substantially contained in said superposition midplane; and in which, during the mechanical treatment of said multifilament billet preceding the synthesis heat treatment, a rolling force is applied in a direction perpendicular to the superposition midplane, and at least one of the side edges of the rolled billet is cut off perpendicularly to the superposition midplane, thereby revealing the matrix of compatible silver alloy.

Abstract: The invention relates a powder in tube type method of making an HTc superconductive multifilament strand having a silver-based matrix, in which:

Abstract: The invention relates a powder in tube type method of making an HTc superconductive multifilament strand having a silver-based matrix, in which: a first envelope is filled with powder reagents for an HTc superconductor; the resulting billet is drawn down into a monofilament strand; the monofilament strand is cut up into lengths and a secondary envelope is filled with the resulting lengths, thereby making a multifilament billet which is drawn down into a multifilament strand; the multifilament strand is cut up into lengths and a new envelope is filled with the resulting lengths, thereby making a new multifilament billet which is drawn down into a new multifilament strand; and it is shaped and subjected to heat treatment; according to the invention, at least one face of the monofilament strand is electrically insulated; and during the first multifilament step the secondary envelope is filled with the resulting insulated lengths.

Abstract: 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.

Abstract: A method of connecting a high critical temperature superconductive ceramic part and a low critical temperature superconductor such as a multifilament strand of niobium-titanium, in which method a silver contact is prepared on said ceramic part, wherein said multifilament strand is soldered to said contact using an intermediate solder material whose melting temperature is less than 300.degree. C.

Abstract: 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.