Phase transitions and electrical characterizations of (K0.5Na0.5)2x(Sr0.6Ba0.4)5−xNb10O30 (KNSBN) ceramics with ‘unfilled’ and ‘filled’ tetragonal tungsten–bronze (TTB) crystal structure
Phase transitions and electrical characterizations of (K0.5Na0.5)2x(Sr0.6Ba0.4)5−xNb10O30 (KNSBN) ceramics with ‘unfilled’ and ‘filled’ tetragonal tungsten–bronze (TTB) crystal structure
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DOI：
10.1016/j.jeurceramsoc.2012.07.034
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发表时间：
2012-12
影响因子：
5.7
通讯作者：
Y. B. Yao;C. Mak;B. Ploss
中科院分区：
文献类型：
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作者：
Y. B. Yao;C. Mak;B. Ploss
采用固相反应法制备了碱金属掺杂的钛酸锶钡（K0.5Na0.5）2x（Sr0.6Ba0.4）5−xNb10O30（KNSBN）陶瓷。碱金属掺杂剂浓度x从0.24变化到1.15，使得晶体结构从“未填充”转变为“填充”四方钨青铜（TTB）结构。除了结构性质的变化，碱金属掺杂剂的相变以及铁电，压电和热释电性能的影响也进行了研究。在−200°C至350°C的温度范围内研究了相变。这些相变的起源进行了讨论。碱金属掺杂提高了KNSBN陶瓷的铁电、压电和热释电性能。碱掺杂也有利于异常晶粒生长，从而导致多孔的微观结构，这可能有助于提高热释电性能。
Alkali-doped strontium barium niobate (K0.5Na0.5)2x(Sr0.6Ba0.4)5−xNb10O30(KNSBN) ceramics has been prepared by a conventional solid-state reaction method. The alkali-dopant concentration x has been varied from 0.24 to 1.15 so that the crystal structure was transformed from ‘unfilled’ to ‘filled’ tetragonal tungsten–bronze (TTB) structure. Apart from the change in the structural properties, the effects of the alkali-dopants on the phase transition as well as ferroelectric, piezoelectric and pyroelectric properties have also been investigated. Phase transitions have been studied in the temperature range of −200°C to 350°C. The origins of these phase transitions are discussed. The addition of the alkali-dopants enhances the ferroelectric, piezoelectric and pyroelectric properties of the KNSBN ceramics. Alkali-doping also favors abnormal grain growth and thus results in a porous microstructure, which might contribute to the enhancement of the pyroelectric performance.