Spray Drying of Metal Alkoxide Sol for Strontium Titanate Ceramics |
| |
Authors: | Hari Krishna Varma P. Krishna Pillai Themanam Veettil Mani Krishna Gopa Kumara Warrier Alathoor D. Damodaran |
| |
Affiliation: | Regional Research Laboratory (CSIR), Trivandrum 695 019, India |
| |
Abstract: | Conditions for obtaining a stable sol in an isopropyl alcohol–water medium containing titanium isopropoxide and strontium nitrate, and acetic acid as a modifier, have been described. Spray drying of the sol results in submicrometer spherical agglomerates which on further thermal decomposition yield submicrometer particles of strontium titanate at temperatures as low as 500°C. The thermal decomposition characteristics of the spray-dried precursor and the development of strontium titanate phase have been discussed. Calcined precursor powder possesses a specific surface area of 12m2/g, a comp action density of 57%, and a sintered density of > 98%. The optimum sintering temperature of such a powder was 1450°C, which resulted in a sintered grain size around 1.5 μm. Further, such a sintered sample had a dielectric constant of 260 and a loss factor of 0.008 at 1 kHz. This method appears to be very convenient with respect to handling of stable sols and thus avoids the usual difficulties regarding extended gelation as well as inhomogeneous precipitation. |
| |
Keywords: | |
|
|