摘要
采用固相反应法制备了未掺杂和La2O3掺杂(0.5%、1%、2%(摩尔分数))的Ba0.55Sr0.45TiO3/MgO复合陶瓷材料,并研究了它们的显微结构和各种介电性能。研究结果表明,La2O3除一部分会进入BST晶格獭代Ba或Sr的位置外,还会有一部分与MgO等形成无定形态物质滞留在晶界,起到抑制BST晶粒生长的作用。BST/MgO复合陶瓷的居里温度随La2O3掺杂量的增大而降低,居里温度的降低导致了介电常数的减小。适量的La2O3掺杂提高了复合陶瓷的调谐性,而且La2O3掺杂明显降低了复合陶瓷的微波介电损耗。0.5%(摩尔分数)La2O3掺杂的BST/MgO复合陶瓷具有最佳的综合介电性能,其在10kHz下的调谐性为6.9%(2kV/mm),3.99GHz时的介电常数和介电损耗分别为87.5和3.35×10-3,基本可以满足铁电移相器的使用要求。
Undoped and La2O3 doped （0. 5mol%, 1mol%, 2mol%） Ba0.55Sr0.45 TiO3/MgO composites were prepared by traditional ceramic process-solid phase synthesis and their microstructure and dielectric properties were systemically studied. The results show that a small amount of La^3＋ ions can enter BST lattices to substitute for Ba^2＋ or Sr^2＋. In addition, the amorphous materials formed by La2O3 and MgO segregated in the grain boundary region and inhibited the grain growth of BST. The curie temperature of the composites decreases with the increase of the La2O3 doping content, which results in the decrease of the dielectric constant. The proper content of La2O3 is beneficial to improve the tunability, and La2O3 doping can greatly decrease the dielectric loss of the composite at microwave frequency. For 0.5mo1% La2O3 doped BSTM composite, the tunability at 10kHz is 6.9 %（2kV/mm）, the dielectric constant and the loss at 3.99GHz 87.5 and 3.35 × 10^-3 separately. So it has the improved dielectric properties and can basically meet the requirements of the microwave phase shifters.
出处
《功能材料》
EI
CAS
CSCD
北大核心
2007年第12期2093-2096,共4页
Journal of Functional Materials
关键词
铁电复合陶瓷材料
微观结构
调谐性
ferroelectric composite ceramics
microstructure
tunability
作者简介
通讯作者周洪庆（1963-），男．江苏溧阳人，教授，博士生导师，主要从事信息功能材料的研究。
