DIRECTIONAL SOLIDIFICATION OF COO-ZRO2 EUTECTICS

The directional solidification of CoO-ZrO2 eutectic with and without Y 2O3 has been investigated by the floating zone melting method. A direc tionally solidified structure without cell structure can be grown for both CoO-ZrO2 and CoO-ZrO2-Y2O3 eutectics. The dominant growth morphol ogy in these eutectics was the lamellar structure. The interface of th e lamella has the orientation relationship of (001)cUbC ZrO2\\(111)CoO and steps with periodic spacing. This relation at the interface was r etained even if the ZrO2 phase was transformed to the monoclinic phase from the cubic phase through the tetragonal structure.