Constitution of stable and metastable phase diagrams for TmFeO3-ScFeO3 system by undercooling solidification using the containerless technique

Abstract

Spherical samples of Tm1−xScxFeO3 were solidified from the undercooled melt under the containerless state using an aerodynamic levitation (ADL) furnace. The change of solidification behavior from double recalescence to single recalescence and powder X-ray diffraction (XRD) analysis of as-solidified samples revealed that metastable hexagonal LnFeO3 (h-LnFeO3) stabilizes with increasing of mole fraction of Sc. The reason for this stabilization was ascribed to the decrease of the difference in the liquidus temperatures of stable orthorhombic LnFeO3 (o-LnFeO3) and metastable h-LnFeO3 phases. Annealing the as-solidified samples at 1473 K for 1 hour resulted in the two-phase coexistent states of o−LnFeO3 and garnet (c-A3B5O12) at 0 < x < 0.3, c-A3B5O12 and h-LnFeO3 at 0.3 < x < 0.5, and h-LnFeO3 and c-ScFeO3 at 0.5 < x < 1.0. Based on these results, we proposed the quasi phase diagram between TmFeO3 and ScFeO3.