Preparation of ZrSiO_4 Powders by Sol-Gel Process (Part 2) : Preparation Conditions of ZrSiO_4 Composition Precursor Gels

ZrSiO_4 powders were prepared from partially hydrolyzed solutions of Si(OC_2H_5)_4 (TEOS) and ZrOCl_2 aqueous solutions by the sol-gel processing, and the influence of amount of water for partial hydrolysis of TEOS,pH of the ZrOCl_2, aqueous solution and mixing time on the formation rate of ZrSiO_4 was investigated. The preparation conditions were evaluated by the formation rate of ZrSiO_4 after 1.5 wt% ZrSiO_4 seed crystals were added to the precursor powders and then the powder mixtures were heated at 1200°to 1500℃ for 2h. In the preparation of ZrSiO_4 composition precursor gels from TEOS-ZrO_2 sol and SiO_2 sol-ZrOCl_2, the H_2O/TEOS molar ratio of about 2 and the pH of the ZrOCl_2 aqueous solution of about 3 were appropriate. About 2h were necessary for mixing of partially hydrolyzed solution of TEOS and ZrOCl_2 aqueous solution to improve the homogeneity of precursor sols, and more than 10 h was required for the mechanical mixing of precursor sols. The formation of ZrSiO_4 produced by firing the precursor sols obtained from the partially hydrolyzed solution of TEOS and ZrOl_2 aqueous solution at 1300° to 1400℃ showed an accelerative increase through the Hedvall effect by silica.rights: 社団法人日本セラミックス協会rights: 本文データは学協会の許諾に基づきCiNiiから複製したものであるrelation: IsVersionOf: http://ci.nii.ac.jp/naid/110002289116