Pb-Distribution in a Five-Phase (Bi, Pd)-Sr-Ca-Cu-O Assemblage

Published

March 12, 1998

Author(s)

Lawrence P. Cook, Winnie K. Wong-Ng

Abstract

The partitioning of lead between phases in the nominal five-phase assemblage: (Pb,Bi)₃Sr₂Ca₂CuO_x + (Ca,Sr)₂PbO₄ + (Bi,Pb)₂Sr₂CaCu₂O_x + (Ca,Sr)O + Liquid has been investigated in an atmosphere of 7.5% O₂925% Ar. Samples were studied using a combination of high temperature quenching, simultaneous differential thermal analysis and thermogravimetric analysis, scanning electron microscopy, and energy dispersive x-ray analysis. Results indicate a strong partitioning of lead relative to bismuth into the (Pb,Bi)₃Sr₂Ca₂CuO_x and (Ca,Sr)₂PbO₄ phases, for which the average Pb/(Pb + Bi) ratios were determined to be 0.73 and 0.85, respectively. In the (Bi,Pb)₂Sr₂CaCu₂O_x and Liquid phases, the average Pb/(Pb + Bi) ratios were much lower, 0.14 and 0.24, respectively. This indicates an apparent saturation of Pb in the (Bi,Pb)₂Sr₂CaCu₂O_x superconductor at a relatively low level. Data on Sr/(Sr+Ca) ratios for coexisting phases are also presented, along with a thermodynamically-derived projection of the 5-component data for the coexisting phases.

Proceedings Title

Proceedings Of ACerS

Volume

84

Conference Dates

May 1, 1997

Conference Title

ACerS

Pub Type

Conferences

Keywords

BSCCO, five phase assemblage, high Tc superconductors, lead distribution, phase equilibria

Citation

Cook, L. and Wong-Ng, W. (1998), Pb-Distribution in a Five-Phase (Bi, Pd)-Sr-Ca-Cu-O Assemblage, Proceedings Of ACerS (Accessed April 19, 2024)