A new solution route to silicates. Part 4.—Subtnicronic zircon powders

Abstract

Submicron-sized zircon powders have been prepared by an aqueous sol-gel process. The starting products were zirconium oxychloride or oxynitrate and a water-soluble silicate. The reaction took place at 120 °C in a PTFE-lined bomb under autogenous pressure or even at 100 °C in refluxing conditions. The resulting powder has been characterized by XRD, IR, EDAX, SEM, TEM and EXAFS. Under pseudo-hydrothermal conditions, zircon was prepared as spherical particles with a very narrow size distribution (mean size 0.6 µm). Crystallinity was improved by thermal curing resulting, at 1100 °C, in disk particles (diameter 0.35 µm; thickness 0.13 µm).