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Data on the YBa2Cu3O7 − x-CuOx phase diagram

1989; Elsevier BV; Volume: 150; Linguagem: Inglês

10.1016/0022-5088(89)90271-3

1878-2728

F. Licci, P. Tissot, Hans J. Scheel,

Superconductivity in MgB2 and Alloys

The YBa2Cu3O7 − x(YBCO)-CuOx phase diagram was determined by differential thermal analysis (DTA), thermogravimetric analysis, hot-stage microscopy, annealing experiments and X-ray identification of phases. YBCO decomposes peritectically to a green phase (Y2BaCuO5) and a liquid consisting of BaCuO2 and CuOx at around 1000–1030 °C, depending on the oxygen partial pressure. As the reversible reaction to form YBCO is sluggish, the DTA experiments indicated low-temperature (eutectic) reactions not belonging to the equilibrium phase diagram. This has consequences for the fabrication of YBCO ceramics and wires. Furthermore, no coexistence region of YBCO and liquid was found, so that YBCO cannot be grown from a "CuOx flux".