Daniel Lam

US Patent:

51734761, Dec 22, 1992

Filed:

Oct 3, 1988

Appl. No.:

7/252698

Inventors:

Boyd W. Veal - Downers Grove IL
John W. Downey - Joliet IL
Daniel J. Lam - Orland Park IL
Arvydas P. Paulikas - Downers Grove IL

Assignee:

The United States of America as represented by the United States
Department of Energy - Washington DC

International Classification:

C01B 1318
C01F 1104
C01G 302
C01G 2900

US Classification:

505 1

Abstract:

A superconductor consisting of a sufficiently pure phase of the oxides of Bi, Sr, Ca, and Cu to exhibit a resistive zero near 110K resulting from the process of forming a mixture of Bi. sub. 2 O. sub. 3, SrCO. sub. 3, CaCO. sub. 3 and CuO into aparticulate compact wherein the atom ratios are Bi. sub. 2, Sr. sub. 1. 2-2. 2, Ca. sub. 1. 8-2. 4, Cu. sub. 3. Thereafter, heating the particulate compact rapidly in the presence of oxygen to an elevated temperature near the melting point of the oxides to form a sintered compact, and then maintaining the sintered compact at the elevated temperature for a prolonged period of time. The sintered compact is cooled and reground. Thereafter, the reground particulate material is compacted and heated in the presence of oxygen to an elevated temperature near the melting point of the oxide and maintained at the elevated temperature for a time sufficient to provide a sufficiently pure phase to exhibit a resistive zero near 110K.