Preparation of NbTi alloy composite superconductor

The superconducting material must be clad, or embedded, in ordinary good conductors to provide a low-resistance bypass when certain line segments suddenly turn to normal. The wrapping is also important in preventing the magnetic field lines from jumping forward. In other words, in order to reduce losses and improve stability, the appropriate basic materials must be used. The choice of matrix material depends on conflicting requirements. Wilson and his colleagues' theory suggests that a highly conductive substrate allows for the use of thinner wires, but its multi-strand cables must be twisted in a tighter spiral. The Germans believe that the main reason why the oxygen free copper with high conductivity is used as the matrix material of superconducting NbTi alloy is that the transport current can be moved to the matrix when the transient disturbance of superconducting state occurs due to local temperature rise, so that the Joule heat that has appeared can be kept at a sufficiently small degree. However, it has been noted that copper, which has good stabilizing properties, has never been able to adequately limit the induced current.