物理化学学报 >> 2011, Vol. 27 >> Issue (08): 2009-2014.doi: 10.3866/PKU.WHXB20110839

材料物理化学 上一篇    

乌青铜型BaNd2Ti4O12微波介质陶瓷的电导和介电损耗

夏海廷1,2, 匡小军3, 王春海1, 李文先2, 荆西平1, 赵飞4, 岳振星4   

  1. 1. 北京大学化学与分子工程学院, 北京分子科学国家实验室, 稀土材料化学及应用国家重点实验室, 北京 100871;
    2. 内蒙古大学化学与化学工程学院, 呼和浩特 010021;
    3. 中山大学化学与化学工程学院, 教育部生物无机与合成化学重点实验室, 光电材料与技术国家重点实验室, 广州 510275;
    4. 清华大学材料科学与工程系, 新型陶瓷和精细工艺国家重点实验室, 北京 100084
  • 收稿日期:2011-04-29 修回日期:2011-06-12 发布日期:2011-07-19
  • 通讯作者: 匡小军, 荆西平 E-mail:kuangxj@mail.sysu.edu.cn. xpjing@pku.edu.cn
  • 基金资助:

    国家自然科学基金(20821091, 21071009, 20423005)资助项目

Conductivity and Dielectric Loss of Tungsten-Bronze-Type BaNd2Ti4O12 Microwave Ceramics

XIA Hai-Ting1,2, KUANG Xiao-Jun3, WANG Chun-Hai1, LI Wen-Xian2, JING Xi-Ping1, ZHAO Fei4, YUE Zhen-Xing4   

  1. 1. Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, P. R. China;
    2. College of Chemistry and Chemical Engineering, Inner Mongolia University, Hohhot 010021, P. R. China;
    3. MOE Key Laboratory of Bioinorganic and Synthetic Chemistry, State Key Laboratory of Optoelectronic Materials and Technologies, School of Chemistry and Chemical Engineering, Sun Yat-Sen University, Guangzhou 510275, P. R. China;
    4. State Key Laboratory of New Ceramics and Fine Processing, Department of Materials Science and Engineering, Tsinghua University, Beijing 100084, P. R. China
  • Received:2011-04-29 Revised:2011-06-12 Published:2011-07-19
  • Contact: KUANG Xiao-Jun, JING Xi-Ping E-mail:kuangxj@mail.sysu.edu.cn. xpjing@pku.edu.cn
  • Supported by:

    The project was supported by the National Natural Science Foundation of China (20821091, 21071009, 20423005).

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摘要：

用固相反应合成了乌青铜型钛酸盐陶瓷BaNd2Ti4O12, 并用电化学阻抗和微波介质谐振测试表征了不同热处理和钽掺杂对电导和微波介电损耗的影响. 电导率随退火气氛(空气, 氧气和氮气)的变化与缺陷反应平衡2OO×↔2VO··+O2↑+2e'和TiTi×+e'↔Ti'Ti随氧分压的变化一致, 表明BaNd2Ti4O12具有n型导电性质. 在空气和氧气中退火有利于减少包括VO×, Ti'Ti和弱束缚电子在内的本征缺陷因而降低电导. 而在低氧分压的氮气中进行退火处理, 增加了缺陷的浓度, 同时提高了电导率. 在空气/氧气/氮气中的退火处理对微波介电损耗没有明显的影响, 表明本征缺陷对微波介电损耗的影响可以忽略. 空气退火处理样品的电导率和微波介电损耗低于空气淬火处理的样品; 其中电导的变化与缺陷反应平衡相关, 但空气退火降低微波介电损耗可能与退火消除晶格热应力有关. 五价钽的掺杂降低了电导但增大了微波介电损耗. 本研究表明空气退火处理能有效地改善BaNd2Ti4O12陶瓷的品质因子Q×f, 其值提高了约12%.

关键词: 缺陷, 电导, 微波介电损耗, BaNd2Ti4O12, 乌青铜结构

Abstract:

Tungsten-bronze type titanate BaNd2Ti4O12 ceramics were synthesized by solid state reactions. The conductivity and microwave dielectric loss of the samples that were thermally treated under various conditions and Ta-doped were investigated by electrochemical impedance measurement and microwave dielectric resonator measurement. The variation in conductivity with annealing atmospheres of air, O2, and N2 was consistent with the defect equilibriums 2OO×↔2VO··+O2↑+2e' and TiTi×+e'↔Ti'Ti, suggesting n-type conductance for BaNd2Ti4O12. Thermal treatment in air/O2 was found to favor the elimination of the native defects VO×, Ti'Ti and weakly bound electrons thus decreasing the conductivity. Thermal treatment in a N2 atmosphere, which had a low oxygen partial pressure, increased the defect content and the conductivity. Thermal treatment in air/O2/N2 did not clearly affect the microwave dielectric loss, suggesting that native defects have negligible effects on this property. The air-annealed sample was found to have lower conductivity and lower microwave loss compared with the air-quenched sample. The change in conductivity was found to be related to the equilibrium of the native defects but the change in microwave dielectric loss might be explained by the release of thermally induced lattice strain. Ta doping reduced the conductivity but increased the microwave dielectric loss. This work shows that air-annealing may be an efficient way to improve the Q×f factor for BaNd2Ti4O12 ceramics, which was enhanced by ~12%.

Key words: Defect, Conductivity, Microwave dielectric loss, BaNd2Ti4O12, Tungsten-bronze