BaTiO_3粉体的预处理及其对陶瓷烧结与介电性能的影响

Effect of Pretreatment of BaTiO_3 Powder on Sintering and Dielectric Properties of Ceramics

以工业生产的BaTiO3粉体为基础原料,探讨不同预处理条件及Sr、Y元素掺量对BaTiO3陶瓷显微结构及介电性能的影响。结果表明:掺杂少量的Sr、Y元素可促进BaTiO3晶体向四方相转变;用乙醇作球磨介质处理粉体并在900℃预烧,可促进陶瓷的致密烧结和晶粒细化;掺杂摩尔分数为1.0%的Sr,可使居里温度降低2℃,室温相对介电常数提高到2 400以上;掺杂Y元素可使陶瓷的居里温度升高,并显著提高陶瓷的介电常数,Y元素掺量为0.3%(摩尔分数)时,室温相对介电常数达到21 000以上。

The influence of different pretreatments and doping amounts of strontium or yttrium on the microstructure and dielectric properties of BaTiO3 ceramics was studied, using industrial produced BaTiO3 as the raw materials. The results showed that the small doping amount of strontium or yttrium promoted the tetragonal changing of BaTiO3 crystals. Using ethanol as the ball-milling media and preheating at 900 ℃ could promote the sintering of ceramic and refinement of crystalline. When the doping amount of strontium was 1.0% （molar fraction）, the Curie temperature of ceramics dropped by 2 ℃, and the relative dielectric constant increased to 2 400. Doping of yttrium raised the Curie temperature and significantly increased the dielectric constant of ceramics. When the doping amount of yttrium was 0.3% （molar fraction）, the relative dielectric constant of the ceramics reached over 21 000 at room temperature.