US 8,522,420 B2Granted

Manufacture of high temperature superconductor coils

AssigneeOxford Superconducting Technology

InventorsSeung Hong, Hanping Maio, Huang Yibing, Maarten Meinesz, Michael Field

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Abstract

A method for successfully heat treating magnet coils of braided Bi2Sr2Ca1Cu2Ox (Bi-2212) strand. The Bi-2212 coil is fabricated using standard round wire powder-in-tube techniques, and braided with a ceramic-glass braid with integrated carbonaceous binder. The coil is heated in an atmosphere controlled furnace below the high current density phase reaction sequence to burn off the carbonaceous binder and evacuated to remove unwanted gases from the inner windings. The oxygen environment is then reintroduced and the coil is heat treated to the high Jc reaction temperature and then processed as normal. As the local atmosphere around the surface of the wire, particularly the concentration of oxygen, is critical to a successful reaction sequence, high current Bi-2212 coils can thereby be obtained.

Claims22

Dependent claims

A method for manufacturing high temperature superconducting coils with electrical insulation, comprising in sequence the steps of:

(a) forming an electromagnet coil device from a winding of superconductive precursor powder-in-tube composite round wire, with the wire turns being separated by a ceramic-glass insulation comprised of a mixture of ceramic and glass fibers and a carbonaceous binder;
(b) removing the binder of the ceramic insulation in a burn-off cycle by combustion in an oxygen-containing environment of a heating vessel at an elevated temperature below the partial melting point of the precursor superconducting powder and ceramic-glass insulation;
(c) evacuating the heating vessel at a reduced temperature at about room temperature;
(d) introducing oxygen gas into the vessel;
and
(e) increasing the temperature in the vessel to the peak reaction heat treatment temperature for forming the ceramic insulated superconducting wire, while said electromagnet coil device is in said vessel.

3 more elements

Dependencies are inferred from the claim text.