Containerless solidification of YBa2Cu3O7-x in a drop tube

Abstract

YBa2Cu3O7-x was molten and resolidified by a containerless process under free-fall conditions in a drop tube. The resulting samples revealed four different microstructures originating either from a “high-temperature melt” (Tm ≥ 1550 K) or from a “low-temperature melt” (1288 K ≤ Tm ≤ 1550 K). All structures exhibited very fine, homogeneously dispersed structural constituents. One of these microstructures is not compatible with actual equilibrium phase diagrams and implies the kinetic suppression of the nucleation of both the Y2BaCuO5- and the Y2O3-phase.