Superconducting Bi2Sr2Ca1Cu2Ox phase formed by penetration throughout metallic copper pipe

One of the biggest disadvantages in high-T-c superconducting ceramics is the difficulty of forming-into a desired shape. This paper shows a new route for fabrication of ceramic superconductors with comp]ex shapes such as pipes, hollow coils, and honeycombs. The melts of Bi-Sr-Ca-Cu-O (BSCCO) were cast and quenched into metallic copper pipes (outer diameter of 5 mm with 0.6 mm thickness)and subsequently the rodlike specimens filled with BSCCO were heat-treated in ordinary air atmosphere at temperatures around 850 degrees C for 50 h. This treatment results in the fabrication of superconducting hollow cylinders, of which the outer surface is covered with superconducting Bi2Sr2Ca1Cu2Ox and the adjacent inner layer consists of copper oxide pipes. It is found that the metallic copper pipe is oxidized during the heat-treatment and the BSCCO melt in the pipe is spontaneously transported throughout the pipe, so that superconducting Bi2Sr2Ca1Cu2Ox layer forms on the resulting copper oxide pipe. By this fabrication method,we-can produce a desirable shape of superconductors such as curved pipes and honeycombs.