ZHANG Xiaofei ¹，ZUO Xiaohua ², NIU Yongbin ³, XIONG Hui ¹

(1. School of Mathematics and Physics, Hubei Ploytechnic University, Huangshi 435003, Hubei, China;

2. School of Chemistry and Chemical Engineering, Hubei Ploytechnic University, Huangshi 435003, Hubei, China;

3. School of Materials Science and Engineering, Wuhan University of Technology, Wuhan 430070, Hubei, China)

Abstract: The superfine powders with nominal composition of Ba_0.6Sr_0.4Ti_O3+x wt.% Li₂O (x = 0 and x = 0.5) were prepared by the citrate method. Sintering and dielectric properties were investigated for the ceramic specimens. 0.5wt.% Li₂O was shown to be highly contributive to reduce the sintering temperature of Ba_0.6Sr_0.4TiO₃ ceramics. In addition, the obtained ceramics displayed preferable dielectric properties.The low-temperature sintering mechanism may be attributed to transient liquid phase sintering. Sintering aid Li₂O and surface carbonation of Ba_0.6Sr_0.4TiO₃ are considered to be the origin of the eutectic liquid phase. Low temperature densification and grain growth process can be explained in terms of dissolution-precipitation mechanism.

Key words: dielectric materials; barium strontium titanate; low temperature sintering; transient liquid phase; dielectric properties