Analysis of High Ic and Jc Bi-2212 Conductors With Dilute Second Phase Additions

Compositional analysis of the Bi2Sr2CaCu2Oy(Bi-2212) and secondary phases in high-current Bi-2212 conductors with dilute (<;1 wt.%) second phase additions was performed. Aluminum or zirconium based oxide secondary phases were added to the powders in work designed to gauge their usefulness as processing aids in the development of long length, high critical current density Bi-2212 wires and tapes. Dilute amounts of the additions did not appreciably change the composition of the Bi-2212 phase in the conductors. In all cases, there was an excess of bismuth and a deficiency of the alkaline earths with respect to the ideal 2212 stoichiometry. Scanning and transmission electron microscopy were used to determine the key microstructural features of these conductors with the dilute additions and relate them to their superconducting properties.