Method for making electrical contact with a superconductive strip conductor
A method for creating electrical contact between a first superconductive strip conductor and a further electrical conductor element, wherein the first superconductive strip conductor is placed in flat contact against a first main surface of a reactive multilayer film in a contact area of the strip conductor, the second main surface, facing away from the first main surface, of the reactive multilayer film is placed in flat contact against the further electrical conductor element, and a permanent electrically conductive connection is formed between the first superconductive strip conductor and the further electrical conductor element by subsequently igniting an exothermic chemical reaction in the multilayer film. An electrical conductor assembly is able to be contacted using such a method.
1. A method for forming an electrical contacting between a first superconducting strip conductor and a further electrical conductor element, wherein the first superconducting strip conductor comprises a superconducting material that provides a first electrical path through the first superconducting strip conductor and an outermost stabilizing layer that provides a backup electrical path through the first superconducting strip conductor, wherein the outermost stabilizing layer is configured to maintain electrical continuity of the first superconducting strip conductor when a resistance of the superconducting material increases, the method comprising:
bringing a contact region of the outermost stabilizing layer of the first superconducting strip conductor into areal contact with a first main surface of a reactive multilayer film,
bringing a second main surface of the reactive multilayer film that faces away from the first main surface into areal contact with the further electrical conductor element,
forming a permanent electrically conductive connection between the first superconducting strip conductor and the further electrical conductor element by subsequently triggering an exothermic chemical reaction in the reactive multilayer film, wherein a reaction temperature of the exothermic chemical reaction is between 1000° C. and 2000° C.,
locally melting a surface of the outermost stabilizing layer during the exothermic chemical reaction so that the permanent electrically conductive connection comprises material of the outermost stabilizing layer, and
wherein a lateral propagation speed of the exothermic chemical reaction and a heat capacity of the first superconducting strip conductor are configured to ensure a temperature of superconducting material adjacent the contact region remains below 200° C. throughout the forming of the permanent electrically conductive connection.
2. The method as claimed in claim 1 ,
wherein the permanent electrically conductive connection formed is a soldered connection between the first superconducting strip conductor and the further electrical conductor element.
3. The method as claimed in claim 2 ,
wherein the soldered connection is formed by a connection layer, a majority of which is formed from materials of the reactive multilayer film.
4. The method as claimed in claim 2 ,
wherein the soldered connection is formed by a connection layer comprising materials of the reactive multilayer film and additionally material of at least one further solder layer.
5. The method as claimed in claim 4 ,
wherein, before the exothermic chemical reaction is triggered, the at least one further solder layer is present as a coating in the contact region of the first superconducting strip conductor and/or as a coating of the further electrical conductor element.
6. The method as claimed in claim 1 ,
wherein the first superconducting strip conductor and the further electrical conductor element are pressed against one another during the triggering of the exothermic chemical reaction.
7. The method as claimed in claim 1 ,
wherein the further electrical conductor element is a second superconducting strip conductor.
8. The method as claimed in claim 1 ,
wherein the further electrical conductor element is a normally conducting contact piece.
9. The method as claimed in claim 1 ,
wherein the triggering of the exothermic chemical reaction is initiated by an electrical triggering pulse, by an optical triggering pulse, and/or a thermal triggering pulse.
10. The method as claimed in claim 1 ,
wherein material of the reactive multilayer film comprises aluminum and/or nickel.
11. The method as claimed in claim 1 ,
wherein the reactive multilayer film has a total thickness in a range of between 10 μm and 300 μm.
12. The method as claimed in claim 11 ,
wherein the total thickness is in a range of between 20 μm and 200 μm.
13. The method as claimed in claim 1 ,
wherein the reactive multilayer film comprises a nanostructured multilayer system.
14. The method as claimed in claim 1 ,
wherein locally melting a surface of the outermost stabilizing layer during the exothermic chemical reaction comprises incipiently melting the outermost stabilizing layer.
15. The method as claimed in claim 1 ,
wherein the lateral propagation speed of the exothermic chemical reaction and the heat capacity of the first superconducting strip conductor are configured such outside the contact region of the outermost stabilizing layer a temperature of the first superconducting strip conductor remains below 100° C. throughout the forming of the permanent electrically conductive connection.
16. A method for forming an electrical contacting between a first superconducting strip conductor and a further electrical conductor element, wherein the first superconducting strip conductor comprises a superconducting material that provides a first electrical path through the first superconducting strip conductor and an outermost stabilizing layer that provides a backup electrical path through the first superconducting strip conductor, the method comprising:
bringing a contact region of the outermost stabilizing layer of the first superconducting strip conductor into areal contact with a first main surface of a reactive multilayer film;
bringing a second main surface of the reactive multilayer film that faces away from the first main surface into areal contact with the further electrical conductor element;
forming a permanent electrically conductive connection between the first superconducting strip conductor and the further electrical conductor element by subsequently triggering an exothermic chemical reaction in the reactive multilayer film, wherein a reaction temperature of the exothermic chemical reaction is between 1000° C. and 2000° C., and wherein the exothermic chemical reaction occurs at a distance of less than 200 μm from the superconducting material;
wherein a lateral propagation speed of the exothermic chemical reaction, a heat capacity of the first superconducting strip conductor are configured to ensure a temperature of superconducting material adjacent the contact region remains below 200° C. throughout the forming of the permanent electrically conductive connection.
17. The method as claimed in claim 16 ,
wherein the exothermic chemical reaction occurs at a distance of less than 100 μm from the superconducting material.