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



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


Current applications of BaO-Y2O3-CuOx 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 Tc 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-CuOx 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 Ba2YCu3Ox, Ba4YCu3Ox, BaY2CuO5, and BaCuO2+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 Ba2YCu3Ox, Ba4YCu3Ox, Ba6YCu3Ox, and BaY2CuO5 was observed. Implications for coated conductor processing of Ba2YC3Ox superconducting tapes are discussed.
Physica C-Superconductivity and Its Applications
No. 1-2


BaO-Y<sub>2</sub>O<sub>3</sub>-CuO<sub>x</sub>, carbonate-free conditions, high T<sub>c</sub> superconductor, phase diagrams


Wong-Ng, W. , Cook, L. and Suh, J. (2002), Subsolidus Phase Relationships of the BaO-Y<sub>2</sub>O<sub>3</sub>-CuO<sub>x</sub> System Under Carbonate-Free Conditions at p<sub>O</sub>d2^^=100 Pa and at p<sub>O</sub>d2^^=21 kPa, Physica C-Superconductivity and Its Applications (Accessed December 6, 2023)
Created August 1, 2002, Updated February 19, 2017