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DTA/TGA Study of Eutectic Melting in the System BaF2-BaO-Y2O3-CuOx-H2O

Published

Author(s)

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

Abstract

Differential thermal analysis and thermogravimetric analysis (DTA/TGA) experiments have been completed in the BaF2-BaO-Y2O3-CuOx-H2O system at various oxygen pressures to determine the effect of adding BaF2 and H2O on the eutectic melting in the system BaO-Y2O3-CuOx. We have investigated the eutectic melting temperature over the range of pO2 = 20 Pa to pO2 = 0.1 MPa under the following conditions: 1) without BaF2 or H2O; 2) with H2O only; 3) with BaF2 only; 4) with both BaF2 and H2O. Results indicate that without BaF2 or H2O, eutectic melting is depressed from 917 C at pO2 = 0.1 MPa to 838 C at pO2 = 1 kPa. At oxygen pressures below 1 kPa, down to pO2 = 20 Pa, no further lowering of eutectic melting temperature was observed. The topologies of the temperature vs. log pO2 curves for various combinations of BaF2 and H2O were similar to that for the experiments without BaF2 or H2O, but all curves were shifted to lower temperatures. For the experiments with addition of BaF2 only, H2O only, and BaF2 with H2O, the eutectic melting temperatures as a function of pO2 were lowered by, respectively, 5 C - 15 C, 15 C - 25 C and 20 C - 30 C. Application of results to the BaF2 ex-situ method of processing Ba2YCu3Ox coated conductors is discussed.
Proceedings Title
High-Temperature Superconductors-Crystal Chemistry, Processing and Properties, Symposium ||High-Temperature Superconductors-Crystal Chemistry, Processing and Properties |Materials Research Society
Volume
659
Conference Dates
November 1, 2000
Conference Title
Materials Research Society Symposium Proceedings

Keywords

Ba<sub>2</sub>YCU<sub>3</sub>O<sub>x</sub>, Ex-situ, process, processing, Superconductors

Citation

Cook, L. , Wong-Ng, W. and Suh, J. (2001), DTA/TGA Study of Eutectic Melting in the System BaF<sub>2</sub>-BaO-Y<sub>2</sub>O<sub>3</sub>-CuO<sub>x</sub>-H<sub>2</sub>O, High-Temperature Superconductors-Crystal Chemistry, Processing and Properties, Symposium ||High-Temperature Superconductors-Crystal Chemistry, Processing and Properties |Materials Research Society (Accessed July 13, 2024)

Issues

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Created July 1, 2001, Updated February 19, 2017