Preparation of ZrSiO<sub>4</sub> Powder Using Sol-Gel Process (Part 1)

Abstract

The effect of temperature, heating rate and addition of ZrSiO4 seed crystals on the preparation of ZrSiO4 powders by the sol-gel process was studied using X-ray powder diffractometry. ZrSiO4 powders have been prepared by different precursors in Zr(OPri)4-Si(OEt)4, Zr(OPri)4-SiO2 sol, ZrOCl2⋅8H2O-Si(OEt)4 and ZrOCl2⋅8H2O-SiO2 sol groups. The formation rate of ZrSiO4 was higher in Si(OEt)4 than in SiO2 sol. The formation rate was influenced by heating rate, and, in particular, increased remarkably below 2.5K/min. When a small amount of commercial ZrSiO4 was added to the powder of precursor composition as seed crystals, ZrSiO4 powder with a purity of 94-96% was formed at 1600°-1650°C. It was found that the addition of seeds results in lowering of the formation temperature of ZrSiO4 by about 100°C. On the other hand, a ZrSiO4 powder of 94-96% purity was obtained by heating the powder of precursor composition at 1300°C for 1h, followed by re-heating at 1600°C for 1h. The results have suggested that the preparation of ZrSiO4 powder of nearly single phase is possible using the sol-gel process by controlling the seedings and/or the two-stage heating.