钐掺杂对钛酸钡锶陶瓷结构和介电性能的影响

采用溶胶-凝胶法制备了系列Sm掺杂的Ba(0.8-3x/2)SmxSr0.2TiO3(x=0,0.001,0.003,0.006,0.008 and 0.010)粉体及陶瓷。利用X射线粉末衍射、扫描电子显微镜和精密阻抗分析表征了样品的结构和性质。X射线衍射结果表明Ba(0.8-3x/2)SmxSr0.2TiO3粉体在800℃预烧2 h后为单一的钙钛矿结构;通过对陶瓷微观形貌研究发现,Sm掺杂可以明显地抑制陶瓷晶粒生长,随着Sm掺杂量的增加,晶粒尺寸由40μm减小到2μm;居里温度随着Sm掺杂量的增加而线性降低,移动速率为10℃/mol%,室温下介电常数呈现先增加后减小的趋势,并在x=0.006时达到最大值7800。

Effect of Samarium Substitution on Structural and Dielectric Properties of Ba0.8Sr0.2TiO3 Ceramics

Samarium substituted Ba(0.8-3x/2)SmxSr0.2TiO3(x=0,0.001,0.003,0.006,0.008 and 0.010) nanopowders were synthesized from alkoxide solution precursor by sol-gel process.The X-ray diffraction studies showed that the Ba(0.8-3x/2)SmxSr0.2TiO3 powders calcined at 800 ℃ for 2 h were single perovskite structures at room temperature.The microstructure investigation showed that Sm substitution caused inhibition of grain growth of the Ba(0.8-3x/2)SmxSr0.2TiO3 ceramics significantly,from 40 to 2 μm.The addition of Sm led to downward shift of Curie temperature(TC) with a rate of 10 ℃/mol%.The dielectric constant was improved significantly with increase of Sm content.The maximum dielectric constant(7800) was observed at 0.6mol% of Sm substitution and the dielectric constant was found to decrease with further increase in Sm content.