Crystallization of Metastable Tetragonal Zirconia from the Decomposition of a Zirconium Alkoxide Derivative

摘要

A zirconium alkoxide derivative, dibutoxybis(acety-lacetonato) zirconium, was polymerized at 120℃ and 300 millitorr for 3 h to form oligomers, as characterized by gel permeation chromatography and Fourier transform infra-red spectroscopy. Pyrol-ysis of the precursor at 675℃ in flowing 5% H_2 in N_2 followed by cooling to room temperature, produced nano-scale, tetragonal ZrO_2 considerably below the tetragonal-to-monoclinic transformation temperature (approximately 1200℃). Subsequent heat treatment of the same precursor in flowing air under otherwise identical conditions produced approximately 8 vol% monoclinic ZrO_2. The possible formation of oxygen vacancies from polymer pyrolysis and their role in nucleating the metastable tetragonal phase are discussed.