摘要
以分析纯的碳酸锶、碳酸钡、碳酸钙、氧化镁和五氧化二铌为原料,采用固相法制备掺杂Ca(Mg)的Sr0.5Ba0.5Nb2O6陶瓷材料。采用X射线衍射仪、扫描电镜和阻抗分析仪,研究掺杂样品的相组成、微观组织和介电性能。研究结果表明,Ca2+掺杂量≤0.23mol时,Ca2+取代钨青铜结构中A位的Sr2+和Ba2+,随Ca掺杂量的增加,SBN晶格常数逐渐减小。介电温谱曲线显示:在150℃和330℃处出现介电双峰;当Ca2+掺杂量≥0.28mol时,出现第二相CaNb2O6,此时对应(Sr,Ba,Ca)Nb2O6的介电峰逐渐消失。Mg掺杂的所有陶瓷样品,XRD谱呈现SBN50与MgNb2O6两相共存的情形。在150℃和310℃处同样出现介电双峰,随着Mg掺杂量增加,介电峰为1个单峰,并移向低温。
Strontium barium niobate, Sr0.5Ba0.5Nb2O6（SBN50） ceramics doped with Ca^2＋ or Mg^2＋ were prepared by solid state reaction route, using strontium carbonate, barium carbonate, calcium carbonate, magnesia and niobium pentaoxide of analytical grade as raw materials. The phase composition, microstructure and dielectric properties were investigated by X-ray diffraction, scanning electric microscope and impedance analyzer. The results show that Ca^2＋ substitution for Sr^2＋ and Ba^2＋ in A-site of tungsten bronze type structure occurs when n（Ca）^2＋≤0.23 mol. The crystal cell volume decreases with the increase of the amount of calcium doping. The dielectric dual peaks at 150℃ and 330℃, which corresponds to the Curie temperature （To） of SBN50 and the phase transition temperature of （Sr, Ba, Ca） Nb2O6 respectively, are observed. The phase of CaNb2O6 comes out and the peak of （Sr, Ba, Ca） Nb2O6 disappears when n（Ca^2＋）≥0.28 mol. The phases of MgNb2O6 and SBN50 coexist for all the samples doped with magnesium. The dielectric dual peaks at 150℃ and 330℃ are also observed. With the increase of the amount of magnesium doping, only the single dielectric peak exists and it shifts toward low temperature.
出处
《中南大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
2009年第1期205-210,共6页
Journal of Central South University:Science and Technology
基金
广西研究生教育创新计划资助项目(2007105950805M23)
关键词
铌酸锶钡
碱土金属掺杂
介电性能
微结构
strontium barium niobate
alkaline earth metal doping
dielectric properties
microstructure
