Abstract: Disclosed herein are superconducting wires. The superconducting wires can comprise a metallic matrix and at least one continuous subelement embedded in the matrix. Each subelement can comprise a non-superconducting core, a superconducting layer coaxially disposed around the non-superconducting core, and a barrier layer coaxially disposed around the superconducting layer. The superconducting layer can comprise a plurality of Nb3Sn grains stabilized by metal oxide particulates disposed therein. The Nb3Sn grains can have an average grain size of from 5 nm to 90 nm (for example, from 15 nm to 30 nm). The superconducting wire can have a high-field critical current density (Jc) of at least 5,000 A/mm2 at a temperature of 4.2 K in a magnetic field of 12 T. Also described are superconducting wire precursors that can be heat treated to prepare superconducting wires, as well as methods of making superconducting wires.

Abstract: A superconducting electrical generator or motor having a plurality of cryostats is described. The cryostats contain coolant and a first cryostat encloses at least one of a plurality of superconducting coils. A first coil is in superconducting electrical communication with a second coil contained in a second cryostat through a superconducting conduction cooling cable enclosing a conductor. The first cryostat and the second cryostat may be in fluid communication through at least one cryogen channel within the at least one superconducting conduction cooling cable. In other embodiments, none of the plurality of cryostats may be in fluid communication and the cable may be cooled by conduction along the conductor from the first or second cryostat, or from both. The conductor may have different segments at temperatures equal to or above the temperature of the coolant and the superconducting conduction cooling cables may be connected through quick connect fittings.

Abstract: A device and method for making a persistent joint allowing end terminations of superconducting MgB2 wire to be joined with a superconducting bridge. Superconducting electromagnetic coils may be joined in series or joining of coil assemblies to current sources and the two ends of a persistent switch. The device includes wire filaments with end preparation exposing reacted MgB2, inserted into a block and surrounded with Mg+B and/or MgB2 in powder, solid, slurry or sol-gel form and subsequently reacted to establish a bridge of superconducting MgB2 electrically connecting the superconducting MgB2 wires. Autonomous operation of the superconducting background magnet coils in magnetic resonance imaging (MRI) and nuclear magnetic resonance (NMR) devices are allowed, or similar devices where autonomous operation of an MgB2 based superconducting magnet is required. The low resistant joint will also be beneficial for other superconducting applications such as fault current limiters, motors, generators, etc.

Abstract: A device and method for continuously forming superconducting wire, and products made therefrom. The method may include providing at least one continuous metal sheathing strip and at least one metal form, continuously forming the at least one continuous metal sheathing strip to form a partially open configuration, continuously filling the partially open configuration with magnesium diboride precursor comprising boron, and a metal form, and closing the partially open configuration thereby enclosing the magnesium diboride precursor comprising boron, and a metal form, to form a closed configuration. Subsequent reduction in diameter and elongation in length of the closed configuration, followed by heat treatment, catalyzes the transformation of the magnesium diboride precursor comprising boron, and the metal form, to magnesium diboride to form the superconducting wire.

Abstract: There is disclosed a continuous process for the formation of a superconducting wire utilizing magnesium diboride powder. The process provides a long length, low cost strand of superconducting wire which can be used in a monofilament or multifilament form.