Nb2O5-Co3O4-La2O3包覆对Ba0.991Bi0.006TiO3微纳米粉体及其陶瓷的微观结构和性能的影响

Effect of Nb_2O_5-Co_3O_4-La_2O_3 coating on microstructure and dielectric properties of Ba_(0.991)Bi_(0.006)TiO_3 nanoparticles and ceramics

目的改善钛酸钡基陶瓷的烧结性能,调控细晶结构,提高介电温度稳定性。方法通过沉淀包覆法将Nb_2O_5、Co_3O_4和La_2O_3包覆在Ba_(0.991)Bi_(0.006)TiO_3微纳米粉体表面,重点研究了La_2O_3包覆量和烧结温度对Ba_(0.991)Bi_(0.006)TiO_3@Nb_2O_5-Co_3O_4-La_2O_3(BBT@NCL)陶瓷的相组成、微观形貌和介电性能的影响。结果随着La_2O_3包覆量的增加,陶瓷的介电常数呈先增大后减小的趋势,在最佳La2O3包覆量(摩尔比)为0.3%和烧结温度为1 220℃时,陶瓷晶粒的平均尺寸为280nm,室温介电常数达到2 862,介电损耗为0.006 7,所有陶瓷样均满足X8R特性。结论通过沉淀包覆法能够得到具有"芯-壳"结构并满足X8R特性的低烧细晶陶瓷材料。

Purposes-To improve the sintering performance of barium titanate-based ceramics, to regulate the structure of fine grains and to increase the stability of dielectric temperature. Methods- The micro-nano powder of Ba0. 991Bi0.006 TiO3@ Nb2O5 - Co3O4 - La2O3 （BBT@ NCL） are prepared via precipitation method and the effects of the coating amounts of La2O3 and sintering temperature on the microstructure, phase constitution and dielectric properties of BBT@NCL ceramics are also investiga- ted. Results-The dielectric properties increase firstly and then decrease with the increase of La203 content. When the optimum La2O3 molar ratio is 0.3% and the sintering temperature of the ceramic is 1 220℃, the average grain size of BBT@NCL ceramics is 280 nm, dielectric constant is 2 862 at room temperature, dielectric loss of 0. 006 7, all samples satisfy X8R specification. Conclusion-These results show that the BBT@NCL of X8R-type ceramics, with a fine-grained microstructure and excel- lent dielectric properties, are obtained at low sintering temperature with chemical coating method.