Influence of penetration time on the structure and conductivity of Sin-modified BaTiO_3 powders

摘要

In this study BaTiO_3 powders were prepared by the sol-gel method. And the gaseous penetration technique was adopted to improve the conductivity of the BaTiO_3 powders. The resistivity of BaTiO_3 powders decreased from 4.3 × 10_9 to 1.75 × 10_3 Ωm as the penetration time increased from 1 to 5 hand then increased to 3.43 × 10_3 Ω m with further increase of penetration time to 6 h. Intricate reactions related to Sm took place during the penetration process, and the phases of Ba_4Ti_2O_(27), BaSm_2Ti_4O_(12), and BaSm_2O_4 were detected. The gases penetration led to low Po2 condition, the substitution of Sm~(3+) for Ti~(4+) and the Ti-rich state after penetration. The results indicated that increasing of the penetrative time help to the increase of the Sm content, the growth and fusion of the grains and the decrease of the resistivity. The penetration time is one of the critical factors which influence the effect of penetration and the best penetration time is 5 h. In addition, the authors also suggest that the Sm-modified BaTiO_3 powders will be favorable to get low cost conductive powders.