A method of preparing wires or tapes including Bi-2223 superconductor material by providing oxide and carbonate sources of Bi, Sr, Ca, Cu and Pb, milling the material for a time not to exceed about 30 minutes but preferably not greater than 20 minutes to produce a homogeneous mixture. Then heat treating by calcining the milled mixture at a temperature of at least about 830.degree. C. for a time not less than about 12 hours, followed by at least one additional milling for a time not to exceed about 20 minutes and one additional heat treatment, to produce an oxide powder having an average diameter in the 4 to 5 micron range. Then a silver or silver alloy tube is filled with the oxide powder, and shape formed into a rectangular tape. Then alternately thermally treating and mechanically working the tube filled with oxide powder by heating the filled tube to an elevated temperature of about 835.degree. C. to 840.degree. C. and reducing the diameter of the tube, repeating the thermal and mechanical treatment. The filled tube is held at the elevated temperature for a total time in the range of from about 48 hours to about 350 hours to provide Pb.sub.0.4, Bi.sub.1.8 Sr.sub.2.0 Ca.sub.2.2 Cu.sub.3 O.sub.x where x is between 10 and 11.
CONTRACTUAL ORIGIN OF THE INVENTION
The United States Government has rights in this invention pursuant to Contract No. W-31-109-ENG-38 between the U.S. Department of Energy and The University of Chicago representing Argonne National Laboratory.