Effect of Ag on the Primary Phase Field of High Tc (Bi,Pb)-2223 Superconductor

Published

February 1, 2000

Author(s)

Winnie K. Wong-Ng, Lawrence P. Cook, W Greenwood, Anthony J. Kearsley

Abstract

The subsolidus equilibria and the primary phase field (crystallization field) of the 110K high T_c (Bi,Pb)-2223 ([Bi,Pb]:Sr:Ca:Cu) superconductor in the presence of Ag have been determined under 7.5 volume % O₂ (92.5 % Ar). A total of 29 six-phase volumes that include the (Bi, Pb)-2223 and Ag phases as components was obtained. These subsolidus volumes retain the same phase relationships as compared to those without the presence of Ag. The range of initial melt compositions of the 29 volumes expressed in mole fraction % covers BiO_1.5 from 5.6 % to 25.3 %, PbO from 0.4 % to 13.8 %, SrO from 8.4 % to 31.9 %, CaO from 12.2 % to 33.3 %, CuO from 21.7 % to 40.9 %, and Ag from 1.2 % to 6.3 %. Based on these data, the primary crystallization field for the (Bi,Pb)-2223 phase in the presence of Ag was constructed using the convex hull technique. A section of this volume was portrayed by holding the AgO_1.5, SrO and CaO components at the median value of the 29 compositions while allowing projection on the other three axes (BiO_1.5, PbO, and CuO). Ag lowers the melting temperature of al 29 volumes and its presence on the melt composition appears to reduce the Pb concentration while enhancing the entry of Sr. The applications of the liquidus data are discussed.

Citation

Journal of Materials Research

Volume

15

Issue

No. 2

Pub Type

Journals

Keywords

2223 superconductor, BSCCO, effect of Ag, phase equilibria, primary phase field

Citation

Wong-Ng, W. , Cook, L. , Greenwood, W. and Kearsley, A. (2000), Effect of Ag on the Primary Phase Field of High T_c (Bi,Pb)-2223 Superconductor, Journal of Materials Research (Accessed April 18, 2024)