High Tc Bi2Sr2CaCu2Ox Superconducting Powder and Wires for High Field Magnets

This SBIR program will develop improved process methods for preparing Bi 2212 powder synthesized using solution based techniques production of high temperature superconducting wire. Two synthesis techniques will be investigated to produce precursor powder: precipitation and combustion. These precursors will be heat treated using a modified low-pressure calcination approach to obtain desired powder characteristics, such as phase purity, compositional homogeneity, carbon content, stoichiometry, particle size and morphology, and tap density. The resulting powder will be used by our partner OST (Oxford Superconductor Technology) to prepare standard 85 x 7 filament round wires. The microstructure and the performance of the wire will then be correlated with the powder characteristics. The performance of a wire depends on the interplay between powder characteristics, wire drawing process variables and configuration, and thermal processing of the wire. Powder Processing conditions, and powder morphology and size will be optimized to increase the core density of the superconducting fraction in the wire. Efforts to minimize porosity due to gas evolution during thermal processing of wires will also be made. The engineering critical current density, JE, as a function of magnetic field will then be measured at 4.2 K. This project is expected to provide an alternative U.S. source for Bi212 powder, which is desired by OST and others interested in high temperature superconductors