Published online by Cambridge University Press: 31 January 2011
This study investigates the influences of Y–Ba–Cu–O compounds solidification under different oxygen partial pressures by a zone melting method. In the Y–Ba–Cu–O system, P(O2) ranged from 0.02 to 1 atm, and the following reaction occurred during heating: YBa2Cu3O6−δ (Y123) → Y2BaCuO5 (Y211) + L. With an increase of oxygen partial pressure or decrease of pulling rate, the morphology of the solidified interface changed from mushy to equiaxed, cellular, and planar. The continuous Y123 grains were readily obtained under high oxygen partial pressure. Based on the constitutional supercooling theory and combining the result of the yttrium solubility limit for different oxygen partial pressures, the influences of oxygen partial pressure on Y123 morphological evolution were clarified.