AQUEOUS SOL-GEL SYNTHESIS OF POWDERS IN THE ZRO2-SIO2 SYSTEM USING ZIRCONIUM FORMATE AND TETRAETHOXYSILANE

Gels of composition xZrO2-(100-x)SiO2, with x = 10, 30 and 50 mol%, are prepared at various conditions using zirconium formate and tetraethoxysilane as precursors. The reaction medium is an aqueous solution of formic acid instead of conventionally applied alcohol. The effect of temperature and the mole ratio of water and tetraethoxysilane on gelation time are studied. Gels are heat treated at 100, 600, 900 and 1100-degrees-C. Physical features of ZrO2 particles and of the gel matrix are investigated by X-ray powder diffraction and infrared spectroscopy after each step of the heat treatment.