Intergranular Stress Induced Phase Transition in CaZrO3 Modified KNN‐Based Lead‐Free Piezoelectrics
Intergranular Stress Induced Phase Transition in CaZrO3 Modified KNN‐Based Lead‐Free Piezoelectrics
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DOI：
10.1111/jace.13461
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发表时间：
2015-04
影响因子：
3.9
通讯作者：
Feng Chen;Yuan-Hang Li;Guan-Yin GAO;Fang-Zhou Yao;Ke Wang;Jingfeng Li;Xiaolin Li;Xingpeng Gao;Wenbin Wu
中科院分区：
文献类型：
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作者：
Feng Chen;Yuan-Hang Li;Guan-Yin GAO;Fang-Zhou Yao;Ke Wang;Jingfeng Li;Xiaolin Li;Xingpeng Gao;Wenbin Wu
用X射线衍射和拉曼散射研究了CaZrO_3掺杂（Nb_（Na0.49K0.49Li0.02）Ta_（0.2））O_3无铅压电材料（LKNNT-CZ_5）的相变温度。结果表明，相同晶粒尺寸（约2- 5 μ m）的LKNNT-CZ 5陶瓷和粉体的相变行为随温度的变化有明显的差异。陶瓷块体在室温（RT）下被粉碎成粉末后，其正交相突然转变为四方相结构，并且随着温度的升高遵循相变顺序：正交相（RT-65 ° C）、正交相和四方相（65 ° C-105 ° C）、以及四方相（105 ° C至类似于220 ° C）。相比之下，粉末在整个温度范围内（RT-220 ℃）保持四元结构而没有任何相变。这些差异可能是由存在的内应力或残余应变引起的，这些内应力或残余应变可以在磨削过程中释放。
The phase transition temperatures of CaZrO3-doped (Na0.49K0.49Li0.02)(Nb0.8Ta0.2)O-3 lead-free piezoelectrics (LKNNT-CZ5) have been studied with X-ray diffraction and Raman scattering. It is found that LKNNT-CZ5 ceramics and powders with the same crystallite size (similar to 2-5m) exhibit distinctly different phase transition behaviors versus temperature. The ceramic bulk changes its orthorhombic phase to tetragonal structure abruptly after being pulverized to powders at room temperature(RT), and follows a phase transition sequence with increasing temperature: orthorhombic (RT-65 degrees C), orthorhombic and tetragonal (65 degrees C-105 degrees C), and tetragonal phase (105 degrees C to similar to 220 degrees C). Contrastively, the powders hold a tetragonal structure without any phase transition within the whole temperature region (RT-220 degrees C). These differences might be induced by the existing internal stress or residual strain, which could be released during the grinding process.