Patent ID: 7456134
Filing Date: 2008-11-25
Classification: H01L,Y10S,Y10T

Abstract:
1. A process for the continuous production of magnesium diboride based superconductors in the form of rods, wires, strips or tapes, the process comprising the steps of: a) packing an one-end closed metal tube through the open end thereof with a mixture of finely grounded magnesium powder and amorphous boron powder in an atomic ratio in the range of 1:1.8 to 1: 2.2, optionally with one or more additives, b) evacuating said tube through the open end thereof under a vacuum of about 0.01 torr and flattening the unfilled portion of the tube, at a pressure of about 1 GPa, c) sealing the open end of the packed tube by cold welding without any flux, d) deforming the sealed tube by groove or flat rolling to obtain the shape of a rod or a strip, and e) (i) electrical self-heating the rod or strip obtained in step (d) with hot rolling to a temperature of about 800° C. by passing a suitable current therethrough for about 30 minutes, followed by annealing by electrical self-heating and cooling down to room temperature to obtain a mono filamentary magnesium diboride superconducting rod, wire, strip or tape, or (ii) packing a plurality of rods or strips obtained in step (d) into another metal tube, deforming the metal tube by groove or flat rolling to obtain a rod or strip, electrical self-heating the rod or strip with hot rolling to a temperature of about 800° C. by passing a suitable current therethrough for about 30 minutes, followed by annealing by electrical self-heating and cooling down to room temperature to obtain multifilamentary magnesium diboride based superconductors in the shape of a wire or a tape.