Particle sizes effects on electrical properties and densification of laminated Ba1.002La0.003TiO3 ceramics

This paper investigated the influences of initial particle sizes on electrical properties and densification of laminated Ba_1.002La_0.003TiO₃ ceramics prepared by the reduction–reoxidation technique. Ba_1.002La_0.003TiO₃ powders with average size of∼820 nm and∼260 nm were prepared by the planet ball milling and the sand milling, respectively. For ceramic samples from ∼260 nm particles, the inflection point where the densification rate begins to decrease occurs at a higher sintering temperature than that of ceramic samples from∼820 nm particles. An abnormal growth of grains is observed in ceramic samples from∼820 nm particles, which resists reoxidation. Samples from∼260 nm particles are prone to be globally reoxidized and exhibit a much greater change in grain boundary resistance and RT resistivity after reoxidation. A possible mechanism of the oxygen diffusion in the reoxidation process is proposed, which verifies that samples with smaller grains as well as lower density are easily oxidized to a deeper degree.