物理化学学报 >> 2008, Vol. 24 >> Issue (08): 1405-1410.doi: 10.1016/S1872-1508(08)60060-1

研究论文 上一篇    下一篇

锰掺杂Ba0.6Sr0.4TiO3-MgTiO3复相陶瓷的制备和介电性能

李明利, 徐明霞, 梁辉, 李晓雷, 徐廷献   

  1. 天津大学材料科学与工程学院, 教育部先进陶瓷与加工技术重点实验室, 天津 300072
  • 收稿日期:2008-02-29 修回日期:2008-05-04 发布日期:2008-08-06
  • 通讯作者: 徐明霞 E-mail:xumingxia@tju.edu.cn;lml@tju.edu.cn

Preparation and Dielectric Properties of Mn-Doped Ba0.6Sr0.4TiO3-MgTiO3 Composite Ceramics

LI Ming-Li, XU Ming-Xia, LIANG Hui, LI Xiao-Lei, XU Ting-Xian   

  1. Key Laboratory for Advanced Ceramics and Machining Technology of the Ministry of Education, School of Materials Science and Engineering, Tianjin University, Tianjin 300072, P. R. China
  • Received:2008-02-29 Revised:2008-05-04 Published:2008-08-06
  • Contact: XU Ming-Xia E-mail:xumingxia@tju.edu.cn;lml@tju.edu.cn

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摘要： 以分析纯的Ba(NO3)2、Sr(NO3)2、草酸和钛酸丁酯为原料, 采用草酸盐共沉淀法制备了钛酸锶钡（Ba0.6Sr0.4TiO3, BST）纳米粉体. XRD和SEM分析结果表明, 该方法制备出立方相的Ba0.6Sr0.4TiO3粉体, 平均粒径小于100 nm, 具有较高的烧结活性. 用传统固相法制备了锰掺杂钛酸锶钡-钛酸镁(Ba0.6Sr0.4TiO3-MgTiO3, BST-MT)复相陶瓷, 系统研究了掺杂0.1%-2.0%(x, 摩尔分数, 下同)锰对钛酸锶钡-钛酸镁复相陶瓷微观形貌和介电性能的影响机理. 结果表明, 当锰的掺杂量小于1.5%时, Mn作为受主掺杂取代占据钙钛矿ABO3的B位, 因此导致居里点略微向高温偏移和相变扩散的发生, 锰的掺杂导致晶格畸变, 促进了晶粒生长, 使晶界相比例下降, 因此介电损耗随着锰掺杂量的增大而减小; 当锰的掺杂量为1.5%时, 介电损耗达到最小值, 继续增大掺杂量, 介电常数下降, 介电损耗上升.

关键词: 钛酸锶钡, 锰掺杂, 微观形貌, 介电性能

Abstract: Barium strontium titanate (Ba0.6Sr0.4TiO3, BST) nano-powders were prepared using Ba(NO3)2, Sr(NO3)2, oxalic acid dehydrate, and tetrabutyl titanate (Ti(OC4H9)4) as precursors by the chemical co-precipitation method. The product was characterized by thermogravimetry-differential scanning calorimetry (TG-DSC) thermal analyses, X-ray diffraction (XRD), and scanning electron microscopy (SEM). The experimental results indicated that the resulting Ba0.6Sr0.4TiO3 nano-powders were homogeneous with agglomerated nature. The Ba0.6Sr0.4TiO3-MgTiO3 (BST-MT) bulk composite ceramics doped by Mn were obtained by the traditional solid phase method. The XRD patterns demonstrated that Mn-doped BST was unable to change the perovskite crystalline structure of BST materials. SEM photographs revealed that the crystalline grains became larger with increasing the content of doping Mn (<1.5% (x, molar fraction)) and then the size of grains decreased after the Mn content exceeded 1.5%in the BST ceramics, suggesting the effect of Mn doping on the morphologies of BST-MT composites. The dielectric properties of BST-MT composite ceramics doped with 0.1%-2.0% (x)Mn were investigated systematically. Two effects of Mn doping on the dielectric properties of the BST-MT composite ceramics were observed. At low Mn doping concentrations (<1.5%), Mn mainly acted as an acceptor dopant to replace Ti at the B site of ABO3 perovskite structure, leading to a diffused phase transition. It was also observed that the grain size increased drastically as the Mn content increased and thus caused the decrease of dielectric loss. At higherMn doping concentrations (>1.5%), the grain size decreased and the suppression of permittivity and the drastic increase of the dielectric losses were observed, which indicated a“composite”mixing effect.

Key words: Bariumstrontiumtitanate, Mn doping, Microstructure, Dielectric property

MSC2000: 

  • O649