Electrical properties, synthesis and characterization of BaTiO₃ by the sol-gel method and sol-precipitation

Full text: Barium titanate is a material of great importance for the electronics industry because of its electrical properties. In this work the barium titanate was synthesized from the same precursors by the sol-gel method and sol-precipitation. The objective of this work is to analyze and compare the two processes for obtaining a crystalline BaTiO₃ in the context of the microstructure and dielectric properties. Using the sol-gel method, a solution of barium acetate with acetic acid was reacted with another solution containing tetraisopropyl orthotitanate dissolved in 2-propanol. Samples of the obtained gel were calcined at 600 °C, 800 °C and 1000 °C. In alkaline medium, by the sol-precipitation method, tetraisopropyl orthotitanate was reacted with acetylacetone and water. To this solution was added a concentrated solution of KOH, with the formation of a precipitate. The precipitate was reacted with a barium acetate solution at 100 °C under stirring. The powders were washed with deionized water and oven dried at 110 °C. The products will be characterized by DRX, TGA/DSC, FTIR and MEV. The calcined powders will be sintered at 1350 °C and dense ceramic bodies will have their dielectric constant determined. It is expected that the results of these analyzes may indicate the possibility of obtaining stoichiometric, homogeneous powders with high purity of BaTiO₃ from barium acetate precursors and tetraisopropyl orthotitanate and may reveal microstructural and dielectric characteristics of the obtained products. The production of low temperature crystalline BaTiO₃ powders without additional calcination by the sol precipitation method can reduce manufacturing costs while maintaining end product characteristics through process control [1]. References: [1] Phule, P. P. and Risbud, S. H., Materials Science and Engineering vol. 3, pp. 241–247 (1989). (author)