Effect of temperature schedule on the particle size of barium titanate during solid-state reaction

摘要

Nano-sized BaTiO_3 particles were synthesized by a solid-state reaction in air using a 2-step heat treatment process. The dependence of the particle size and tetragonality (=c/a) on the temperature schedule was investigated. The temperature was held for 10 h at an intermediate temperature before heating to the target temperature of 1000℃ for 1 h. Although more heat was consumed, the powders synthesized by the 2-step heat treatment method showed a much smaller particle size with higher tetragonality than those produced by direct heating. For example, the mean particle size was <100 nm at a holding temperature ranging from 500-700 ℃, while it was 246 nm for direct heating to the same target temperature of 1000 ℃. This was explained by the enhanced nucleation rate during temperature holding stage based on the TG/DTA and high temperature XRD results.