Process for the development of NbTi alloy composite superconductors

Superconducting materials must be encapsulated, or buried within a normal good conductor, to provide a low resistance to the side path when certain segments of the line suddenly switch to normal. In addition, the envelope is important in preventing the magnetic lines of force from jumping in. In other words, in order to release low losses and improve stability, it is necessary to use a suitable base material. The selection of the base material depends on conflicting requirements. The theory of Wilson and his colleagues suggests that the use of highly conductive base allows the utilization of thinner wires, but its multi-stranded cables must be more tightly spiral twist. Germans believe that the main reason for choosing highly conductive oxygen-free copper as the matrix material for the superconducting material NbTi alloys is that when the superconducting state is transiently perturbed locally due to an increase in temperature, the transport current can be shifted to the matrix, allowing the Joule heat that has developed to be maintained at a sufficiently small level. However, it has been pointed out that copper, which has good stabilizing properties, has not been able to limit the induced current sufficiently.