The Development of a Two-Powder Process for Bi-2212 Precursor Powders

Bi$_{2}$Sr$_{2}$Ca$_{1}$Cu$_{2}$O$_{y}$ (Bi-2212) is a prime candidate for high-field ($>$20 T) superconducting magnet applications, as it can be formed into a round wire conductor, a unique characteristic among all the high-temperature supercondutors (HTS) discovered to date. Round wires are manufactured by conventional oxide powder-in-tube processes (OPIT). A critical part of this process is the quality of the starting oxide powder precursor, affecting the drawing processes to form wire, the development of the superconducting phase in-situ during heat treatments and the connectivity along the wire length. To better manipulate the partial-melt behavior while better controlling the formation of 2212 by reducing the number of phases present, as 2-powder process was developed. A set of anneals has been completed on the resulting precursor powder. Initial characterization indicates the process can produce Bi-2212, though further development is necessary.