Atomic scale structure of alcohol-based zirconia xerogels by X-ray diffraction

Abstract

The structural evolution of zirconia thin films and gel powders obtained from an alkoxide precursor has been evaluated by X-ray diffraction (XRD). The results indicate that the topological short-range structure (<5 Å) of amorphous alcohol-based zirconia materials is independent of the product form (gel powders or thin films). However, the short-range structure depends on the processing temperature. For temperatures below ∼340°C, local atomic ordering of both ZrO 2 gel powders and films resembles that of crystalline monoclinic ZrO 2. An alcoxolation mechanism appears to control thin films polymerization processes, while an oxolation mechanism appears responsible for ZrO 2 gel powders polymerization. At higher temperatures, the local atomic structure of both amorphous ZrO 2 gel powders and films resembles that of crystalline tetragonal ZrO 2 polymorph. Tetragonal ZrO 2 crystallites were also observed by XRD analysis in all ZNP-based zirconia samples processed above 340°C.