Subsolidus Phase Relationships of the BaO-Y2O3-CuOx System Under Carbonate-Free Conditions at pOd2^^=100 Pa and at pOd2^^=21 kPa

Published

August 1, 2002

Author(s)

Winnie K. Wong-Ng, Lawrence P. Cook, J Suh

Abstract

Current applications of BaO-Y₂O₃-CuO_x phase equilibria are focused on the use of coated conductor technology for fabrication of superconducting tape. Although such processing is typically carried out with carbonate-free high T_c precursors, the majority of phase equilibrium studies completed to date have utilized BaCO₃-derived starting materials. The present study reports results of a BaO-Y₂O₃-CuO_x phase equilibrium investigation at two oxygen pressures using carbonate-free precursors based on BaO. Special apparatus and procedures for handling these atmospherically sensitive compositions are described. Experimental results are used to establish tie-lines in the BaO-rich part of the phase diagram, and have confirmed a difference in tie-line distribution among Ba₂YCu₃O_x, Ba₄YCu₃O_x, BaY₂CuO₅, and BaCuO_2+x phases under carbonate-free conditions relative to those obtained using BaCO₃-derived starting materials. By reducing p02 from 21 Mpa to 100 Pa under carbonate-free conditions, an additional tie-line change among the phases Ba₂YCu₃O_x, Ba₄YCu₃O_x, Ba₆YCu₃O_x, and BaY₂CuO₅ was observed. Implications for coated conductor processing of Ba₂YC₃O_x superconducting tapes are discussed.

Citation

Physica C-Superconductivity and Its Applications

Volume

377

Issue

No. 1-2

Pub Type

Journals

Keywords

BaO-Y₂O₃-CuO_x, carbonate-free conditions, high T_c superconductor, phase diagrams

Citation

Wong-Ng, W. , Cook, L. and Suh, J. (2002), Subsolidus Phase Relationships of the BaO-Y₂O₃-CuO_x System Under Carbonate-Free Conditions at p_Od2^^=100 Pa and at p_Od2^^=21 kPa, Physica C-Superconductivity and Its Applications (Accessed October 9, 2024)