Subsolidus Phase Relationships of the BaO-R2O3-CuOz (R=Tm and Yb) Systems Under Carbonate-Free Conditions at po2 = 100 Pa, and T = 750 Degree Celcius and 810 Degree Celcius

Published

February 19, 2017

Author(s)

Winnie Wong-Ng, Zhi Yang, Lawrence P. Cook

Abstract

For applications of phase equilibria to coated conductor processing, phase diagrams constructed under carbonate-free conditions should be employed. Using special apparatus and a procedure for preparing carbonate-free precursors based on BaO, phase diagrams of the BaO-Tm2O3-CuOz and BaO-Yb2O3-CuOz systems were determined at 100 Pa (0.1% O2 by volume, 750 C and 810 C). The diagrams of the BaO-Tm2O3-CuOz system were confirmed to be similar to those of the Y-, Ho-, and Er systems. The BaO-Yb2O3-CuOz system exhibits different features as compared to the Tm-analog. For example, the Yb-system does not contain the Ba3R4O9 (R=lanthanide) and Ba4RCu3O8.5+z phases. The absence of these two phases affects the tie-line relations in the BaO-rich region of the phase diagram of the Yb-system. Furthermore, while the diagrams with relatively large R (i.e. R=Nd, Sm, Eu, Gd, Dy, Er) do not contain a tie-line between BaCuO2+z and BaR2CuO5, this tie-line was found in the Yb-diagram which has a much smaller R. In general, both the diagrams of the BaO-Tm2O3-CuOz and of the BaO-Yb2O3-CuOz systems prepared under carbonate-free conditions are different from those obtained using BaCO3-derived starting materials.

Citation

Journal of Alloys and Compounds

Pub Type

Journals

Keywords

BaO-R2O3-CuOz (R=Tm and Yb), carbonate-free conditions, coated conductors, phase equilibria

Citation

Wong-Ng, W. , Yang, Z. and Cook, L. (2017), Subsolidus Phase Relationships of the BaO-R₂O₃-CuO_z (R=Tm and Yb) Systems Under Carbonate-Free Conditions at p_o2 = 100 Pa, and T = 750 Degree Celcius and 810 Degree Celcius, Journal of Alloys and Compounds (Accessed January 24, 2025)