Optimization of Current Carrying Capacity in Bi-2212 High Temperature Superconductors

Abstract

Bubbles were considered to be a serious problem happened during the partial melting process of Bi-2212 superconducting wires and tapes, which can interrupt the textural alignment of Bi-2212 grains, block the current transport in single or several filaments, and even cause great damage of the entire wire. Therefore, it is necessary to suppress the formation of bubbles by optimization the traditional powder in tube process. In order to decrease the volume of absorbed H2O and CO2, an extra milling process was adopted on the precursor powders in oxygen atmosphere, as well as the filling process of precursor powders into Ag sheath. The influences of oxygen milling process on the lattice parameter, microstructure, phase evolution mechanism and transport properties were systematically analyzed. Due to the enhanced texture structures, optimized critical current was achieved in both single filament tapes and multi-filament wires. Further optimization of the modified powder in tube process is on the way in order to further improve the transport properties of Bi-2212 wires for practical applications.