The CuO-rich region of the system Y-Ba-Cu-O/K2CO3

Tablets of superconducting YBa2Cu3O7-x, containing various excessive amount s of CuO (0. 2.38, 4.49, 5.69 g Cu per 100 g of the mixture), have been kep t in contact with K2CO3 at 903. 983, 1083 and 1209 K. Thereafter, cross-sec tions of the tablets and the contact zones have been studied by optical mic roscopy. X-ray diffraction, microprobe analyses. Raman spectroscopy and ICP -analyses. As a result of these investigations the existence of a low melti ng phase, probably a K-Cu-O compound, has been revealed. It has been found out that barium ions are dissolved with preference in potassium carbonate. (C) 2001 Elsevier Science B.V. All rights reserved.