FABRICATION OF HIGH-STRENGTH SUPERCONDUCTING WIRES AND TAPES

FABRICATION OF A MULTI-LAYER SUPERCONDUCTING COMPOSITE STRUCTURE ON A HIGH-STRENGTH SUBSTRATE SUCH AS NICKEL-ALLOY OR STEEL IS PROPOSED. THE COMPOSITE LAYERS CONSIST OF A BARRIER LAYER, A SUPERCONDUCTING LAYER, A PROXIMITY LAYER, AND A PROTECTIVE LAYER. PROVISION IS MADE FOR POSSIBLE USE OF MORE THAN ONE LAYER OF SUPERCONDUCTING MATERIAL. THE SUPERCONDUCTING LAYER (ELG. Y-BA-CU-O) MAY BE MIXED WITH SILVER AND ALSO PERHAPS FACED ON BOTH SIDES WITH SILVER LAYERS. THE PRESENCE OF SILVER IS EXPECTED TO IMPROVE THE CONDUCTIVITY WITH NO ADVERSE EFFECT DUE TO HIGH-TEMPERATURE CHEMICAL REACTIONS. TWO CONFIGURATIONS ARE PROPOSED, NAMELY, A TAPE CONFIGURATION AND A WIRE CONFIGURATION. IN THE TAPE CONFIGURATION, A HIGH-STRENGTH TAPE OF NICKEL ALLOY OR STEEL IS USED AND IN THE WIRE CONFIGURATION A NICKEL ALLOY OR STEEL FILAMENT IS USED. ONE SIGNFICIANT ADVANTAGE OF THE TAPE CONFIGURATION IS THAT THE SUPERCONDUCTING COMPOSITE LAYERS CAN BE FORMED ON A SILVER FOIL AND THEN AFTER HIGH-TEMPERATURE ANNEALING BE LAMINATED TO THE HIGH-STRENGTH SUBSTRATE. THIS PROCESS WILL ELIMINATE THE HIGH-TEMPERATURE CHEMICAL REACTION BETWEEN THE SUBSTRATE AND THE COMPOSITE STRUCTURE. IN THE TAPE TECHNOLOGY, TAPE CASTING IS PROPOSED FOR FABRICATION OF THE SUPERCONDUCTING LAYER. IN THE WIRE TECHNOLOGY, UTILIZATION OF BOTH CONVENTIONAL CERAMIC TECHNOLOGY AND THIN FILM TECHNOLOGY (SPUTTERING) IS PROPOSED. THIN FILM TECHNOLOGY (E.G. EVAPORATION OR SPUTTERING) WILL BE USED FOR DEPOSITION OF THE PROXIMITY LAYER IN BOTH THE TAPE AND WIRE TECHNOLOGIES.