RETENTION OF THE METASTABLE TETRAGONAL PHASE IN NANOCRYSTALLINE ZrO_2-CeO_2 POWDERS

摘要

ZrO_2-based solid solutions exhibiting the metastable tetragonal phase have excellent electrical and mechanical properties. However, the conditions required for the retention of the tetragonal phase are not well established yet. In this work, we investigate the stability of the tetragonal phase in nanocrystalline ZrO_2 ― 2 to 15 mol% CeO_2 powders synthesised by a nitrate-glycine gel-combustion process. The phases present in these materials were analysed by X-ray diffraction and Raman spectroscopy. The average crystallite sizes were in the range of 8-14 nm. Fully tetragonal materials were obtained for a CeO_2 content of 5 mol% or higher. It was found that the tetragonal phase is more stable for high CeO_2 content and low crystallite size.