Directional solidification of CoO-ZrO2 eutectics

The directional solidification of CoO-ZrO2 eutectic with and without Y2O3 has been investigated by the floating zone melting method. A directionally solidified structure without cell structure can be grown for both CoO-ZrO2 and CoO-ZrO2-Y2O3 eutectics. The dominant growth morphology in these eutectics was the lamellar structure. The interface of the lamella has the orientation relationship of (001)cubic ZrO2⌈(111)CoO and steps with periodic spacing. This relation at the interface was retained even if the ZrO2 phase was transformed to the monoclinic phase from the cubic phase through the tetragonal structure.