Bi-2223／Ag超导闭合线圈的制备及其电流衰减特性的研究

本文研究了使用Bi-2223／Ag超导带材制备超导闭合线圈的工艺及超导闭合线圈中电流衰减的特性．在闭合线圈焊接点的制作上，分别采用了超导焊接和普通焊锡焊接两种不同方法．通过测量闭合线圈中心点的磁场衰减过程，观察了这两种闭合线圈中电流衰减的特性．实验发现，使用超导焊接技术制备的闭合线圈，电流衰减与时间的自然对数成线性关系，在线圈局部受损伤的情况下，上述关系仍然成立；使用普通焊锡焊接方法制备的闭合线圈，电流衰减不存在上述关系，但也不是时间的e指数函数．

FABRICATION AND DECAY EVALUATION OF Bi-2223/Ag CLOSED HTS COILS

Several closed HTS coils were fabricated using Bi-2223/Ag tape and the current decay property of these closed coils have been studied. Two kinds of method were applied in fabricating the joint of the closed coils, one is the superconducting-joint technique and the other is resistive-joint method. By measuring the magnetic flux density at the center of the coil, the current decay property of the closed HTS coils was observed. Of the superconductingjointed coils, the current decay is linear with the logarithm of times even when the coil is partly broken, this relationship still holds. Of the resistivejointed coils, the current decay shows no such relationship as mentioned above, and it is either not true that the current decay is the exponent of time.