Ultrafine Barium Titanate Powders via Microemulsion Processing Routes

Abstract

Three processing routes have been used to prepare barium titanate powders, namely conventional coprecipitation, single-microemulsion coprecipitation using diether oxalate as the precipitant, and double-microemulsion coprecipitation using oxalic acid as the precipitant. A single-phase perovskite barium titanate was obtained when the doublemicroemulsion-derived oxalate precursor was calcined for 2 h at a temperature of as low as 550°C, compared to 600°C required by the single-microemulsion-derived precursor. A calcination for 2 h at >700°C was required for the conventionally coprecipitated precursor in order to develop a predominant barium titanate phase. It was, however, impossible to eliminate the residual TiO 2 impurity phase by raising the calcination temperature, up to 1000°C. The microemulsion-derived barium titanate powders also demonstrated much better powder characteristics, such as more refined crystallite and particle sizes and a much lower degree of particle agglomeration, than those of the conventionally coprecipitated powder, although they contained ∼0.2 wt% BaCO 3 as the impurity phase.

Tailoring the properties of BaTi0.8Cu0.2O3 catalyst selecting the synthesis method

“…To prepare BaTiO3, a wide variety of synthetic methods have been proposed, including conventional solid-state synthesis [14], co-precipitation [15], micro-emulsion method [16][17][18], spray pyrolysis [19], oxalate route [20], hydrothermal method [21][22][23][24][25][26], microwave-hydrothermal method [27,28], and sol-gel method [1,29,30] among others. The conventional solid-state synthesis typically involves high-temperature calcinations (1200°C) of a BaCO3 and TiO2 powder mixture, which often results in low purity and polydispersity of the final structure due to the high reaction temperature and heterogeneous solid-phase reactions [14].…”

Ultrafine NiFe2O4 powder fabricated from reverse microemulsion process

“…8 To locate the determination between the microemulsion and nonmicroemulsion regions, the aqueous phase was titrated into a mixture of given cyclohexane to surfactant ratio. Thorough mixing of the three components was achieved using a Vortex mixer.…”

Dielectric properties of nano-crystalline BaTiO3 synthesized by micro-emulsion method

“…This involves hydrolysis proceeding in water droplets of inverse micelles as microreactors dispersed in oil. [8][9][10][11][12] Particle sizes are controlled by the diameter of the water droplets in nanometer range. BaTiO 3 particles with a mean size of 8 nm and narrow grain size distribution were obtained by this method.…”