Hydrolysis, condensation, and tetragonal phase formation in sol-gel zirconia prepared with electron-irradiated alkoxide solutions

Sol-gel zirconia precursor, zirconium n-butoxide in ter-butanol, was irradi ated with 1.3 MeV electrons to a dose of 330 KGy. Gelling was instantaneous ly produced when an aqueous solution of sulfuric, hydrochloric or acetic ac id was added to the irradiated solution; no hydrolysis catalyst was require d. Samples were characterized with X-ray powder diffraction, infrared spect roscopy, and electron paramagnetic resonance. The electron irradiation acce lerated hydrolysis and condensation, which avoided the stabilization of the tetragonal phase via carboxyls, and decreased the capability of sulfate io ns to stabilize it. These results suggest that the stabilization of the tet ragonal phase of sol-gel zirconia via carboxyl and sulfate ions depends on their diffusion in the sol.