Karmakar, Basudeb and Ganguli, Dibyendu (1985) Alkoxide hydrolysis and preparation of Ti02 powders. Transactions of the Indian Ceramic Society, 44 (1). pp. 10-14. ISSN 0371-750X

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Abstract

Hydrolysis of titanium isopropoxide was studied under controlled conditions in presence of dry isopropanol. The alkoxide-water interaction presumably proceeded via several intermediate reactions with soluble products; at an advanced stage of reaction, the products of hydrolysis became insoluble, marked by a sudden appearance of uniform turbidity. The rate of hydrolysis, leading to the ultimate formation of an insoluble species, was found to be dependent on the concentration of water and Ti(OPri) 4 in isopropanol, as well as the molar ratios of the reactants. Weight loss experiments showed the precipitated product to be metatitanic acid, TiO(OH)2. Thermal analysis showed a broad endotherm at around 135°C, corresponding to the loss of water, to be the only thermal effect; separate calcinations and X-ray diffraction studies showed that formation of anatase from the amorphous precursor took place around the same temperature. No thermal effect was obtained for the anatase-rutile transformation. However, on treatment of the precipitated powder with NH4OH (used as a dispersant of the particles), an exothermic effect was noted at about 355°C; this was explained to be due to the breakdown of surface-exchanged NH4 ion and partial oxidation of NH3. Electron microscopic studies showed that the initial amorphous TiO(OH) 2 was extremely fine (at least 0.1-0.2 micron), which increased in size on calcination and crystallization to a maximum of 0.5 micron, though agglomeration was a major problem in determining the particle size distribution. © 1984 Taylor & Francis Group, LLC.

Item Type:	Article
Subjects:	Engineering Materials
Divisions:	Sol Gel
Depositing User:	Bidhan Chaudhuri
Date Deposited:	23 May 2016 07:06
Last Modified:	23 May 2016 07:06
URI:	http://cgcri.csircentral.net/id/eprint/3354

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