Sr_(0.3)Ba_(0.7)Bi_(3.7)La_(0.3)Ti_4O_(15)铁电陶瓷的烧结及介电性能

采用两步烧结工艺制备Sr0.3Ba0.7Bi3.7La0.3Ti4O15铁电陶瓷,研究了烧结工艺对陶瓷的晶相和介电性能的影响。结果表明:适当提高最高温度、保温温度和保温时间可改善陶瓷的介电性能。当最高温度为1180～1200℃,在1050～1080℃保温5～15h时,其εr为238～262,tanδ小于10–2,σ为1.0×10–11～10–12S·m–1。该烧结工艺可减少铋的挥发,降低氧空位浓度,因而减弱了陶瓷的高温低频耗散现象。随着保温时间的增加,高温电导得到有效抑制,在1050℃保温15h样品的σ降低了一个数量级,在280℃时为5.2×10–9S·m–1。

Sintering and dielectric properties of Sr_(0.3)Ba_(0.7)Bi_(3.7)La_(0.3)Ti_4O_(15) ferroelectric ceramics

Sr0.3Ba0.7Bi3.7La0.3Ti4O15 ferroelectric ceramics were fabricated by two-step sintering process. The effect of sintering process on crystalline phase and dielectric properties of Sr0.3Ba0.7Bi3.7La0.3Ti4O15 ceramics was investigated. The increase in maximum temperature,dwelling temperature and dwelling time,results in improved dielectric properties. Good dielectric properties,with εr is 238～262,tanδ less than 10–2,and σ is 1.0×10–11～10–12 S·m–1,are achieved at a maximum temperature of 1 180～1 200 ℃,a dwelling temperature of 1 050～1 080 ℃ and a dwelling time of 5～15 h. The decrease in bismuth volatization by two-step sintering results in the decrease in oxygen vacancy and low frequency dispersion at high temperature. The conductivity at higher temperature decreases with increased dwelling time. The conductivity of ceramic specimens with a dwelling time of 15 h at 1 050 ℃ reduces one order of magnitude,and σ is 5.2×10–9 S·m–1 at 280 ℃.