Speaker
Description
A novel Nb3Sn superconducting jointing method by means of powder metallurgy was presented to reduce the resistance for purpose of satisfactory magnetic field stability of high field NMR instrument. In this research, Nb, Sn and Cu element powders were introduced in ball milling processing to prepare the (Cu, Sn) solid-solution before pressing and sintering. The A – 15 type Nb3Sn phase was generated from the element powders during heat treatment. This jointing method is with the character of quick and high quality metallurgical bonding between the Nb3Sn filaments of wires by means of in-situ Nb3Sn phase. The crystal structures and microstructures of the joint were investigated by X-ray diffraction (XRD), Energy-dispersive X-ray spectroscopy (EDX) and scanning electron microscope (SEM) respectively. The critical performance of sinter was also tested by Physical Property Measurement System (PPMS). The joint resistance was measured in the liquid helium condition by the coil current decay method. The results show that the resistance of the joint was decreased sharply in comparison with the soldering and cold-pressing welding methods.
