AN ALTERNATE PREPARATION FOR GRAIN ALIGNED STRUCTURES OF (BI,PB)2CA2SR2CU3OZ

A unique process for the preparation of bulk, grain aligned (Bi, Pb)2Ca2Sr2Cu3O(z), (2223), is presented. The process starts with the magnetic alignment of Bi2CaSr2Cu2O(z) (2122), in a heptane slurry with sufficient particulate PbO, Ca2CuO3 and CuO necessary to form the (2223). Following evaporation of the heptane to physically set the alignment, the compacts are reacted and sintered at high temperature, for long times, to generate the final (2223) product. Critical currents, J(c), on the order of 700 A cm-2 at 77 K and zero magnetic field have been obtained. The severe degradation of J(c) with increasing fields suggests that grain alignment alone is not sufficient criterion for achieving large values of J(c), and that other factors, such as bulk density and connectivity between grains, are of equal or greater importance.