Solidification structure in pure zirconia liquid molten phase

Up to now few studies concerning the crystallographic features of zirconia materials (HZ) used as refractory material have been performed. The elaboration process through raw material fusion followed by a controlled cooling step lead to a material containing 94 wt.% of dendritic monoclinic zirconia. During cooling, ZrO2 passes through three different structural phase transitions (SPTs), inducing formation of a complex microstructure made of different crystallographic domains called variants. This study focus on formation of these different monoclinic variants in a non-doped zirconia based material and the possibility to reconstruct initial cubic parent crystals formed at high temperature using optical microscopy and Electron Back Scattering Diffraction (EBSD). EBSD experiments allow to identify 24 monoclinic variants issued from tetragonal parent crystal and to highlight the contours of the parent cubic crystal. Then, the microstructure appearing during the first steps of the solidification of the material can be evidenced.