CONCENTRATION OF RE (Y, PR, SM, GD, DY, Y B) ELEMENTS IN LIQUID OF BA-CU-O LIQUID REBA(2)CU(3)O(7-DELTA) OR RE(2)BACUO(5) 2 PHASE REGION/

Each solubility of Y, Yb, Dy, Pr and Sm for the Ba-Cu-O melt in air at mosphere was investigated by ICP measurement. The melt compositions we re selected BaCu3O4 for Pr and Ba3Cu5O8 for Other elements because the se compositions were used to fabricate REBa(2)Cu(3)O(7-delta) (RE; rar e earth) by the crystal pulling method. The measurements have been mad e in the temperature range from approximately 1223 K to about 1573 K. According to these results, the liquidus slope of 123 phase/liquid and 211 phase (110 phase in the case of the Pr system)/liquid was determi ned at each peritectic temperature. The solubility of Y for the Ba-Cu- O melt in different O-2 partial pressures and P(O-2) = 2, 21.3, 101 kP a was measured. The decomposition temperature of the Y123 phase increa sed with increasing oxygen partial pressure. However, the effect of ox ygen partial pressure for the Y concentration in the liquid at the tem perature range of Y123+Liquid was relatively small. Furthermore, we es timate the enthalpy of dissolution of RE123, RE211 and Pr110 by a simp le thermodynamic model with regular solution approximation.