Phase-transition temperatures and piezoelectric properties of (Bi1/2Na1/2)TiO3- (Bi1/2Li1/2)TiO3-(Bi1/2K1/2)TiO3 lead-free ferroelectric ceramics
Phase-transition temperatures and piezoelectric properties of (Bi1/2Na1/2)TiO3- (Bi1/2Li1/2)TiO3-(Bi1/2K1/2)TiO3 lead-free ferroelectric ceramics
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DOI：
10.1109/tuffc.2007.566
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发表时间：
2007-12
期刊：
影响因子：
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通讯作者：
Y. Hiruma;H. Nagata;T. Takenaka
中科院分区：
文献类型：
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作者：
Y. Hiruma;H. Nagata;T. Takenaka
研究了x(Bi1/2Na1/2)TiO3-y(Bi1/2Li1/2)TiO3-z(Bi1/2K1/2)TiO3[x+y+z=1](简称BNLKT100y-100z)陶瓷的相变温度和压电性能。这些陶瓷是用传统的陶瓷制造工艺制备的。通过介电、压电性能等电学测量，确定了材料的退极化温度Td、三方-四方相变温度Tr-T和介电最高温度Tm。BNLKT100y-100z的X射线粉末衍射图表明，在z=0.20时，BNLKT100y-100z为三方相和四方相之间的准同型相界(MPB)，并且在MPB处具有最大的压电性。BNLKT4-20和BNLKT8-20的机电耦合系数&33分别为0.603、176pC/N和171℃，压电常数为0.590、190pC/N和115℃。此外，还给出了BNLKT4-100z和BNLKT8-100z的四方边和三方边的D33与Td的关系。综合考虑高Td和高D33，认为BNLKT4-100z的四方晶面是较好的成分。BNLKT4-28的D33和Td分别为135 pC/N和218℃。此外，本研究还揭示了Td的变化与菱形90-α和四方c/a等晶格畸变率的变化有关。
The phase-transition temperatures and piezoelectric properties of x(Bi1/2Na1/2)TiO3-y(Bi1/2Li1/2)TiO3-z(Bi1/2K1/2)TiO3 [x + y + z = 1] (abbreviated as BNLKT100y-100z) ceramics were investigated. These ceramics were prepared using a conventional ceramic fabrication process. The phase-transition temperatures such as depolarization temperatures Td, rhombohedral-tetragonal phase transition temperature TR-T, and dielectric-maximum temperature Tm were determined using electrical measurements such as dielectric and piezoelectric properties. The X-ray powder diffraction patterns of BNLKT100y-100z show the morphotropic phase boundary (MPB) between rhombohedral and tetragonal at approximately z = 0.20, and the piezoelectric properties show the maximum at the MPB. The electromechanical coupling factor &33, piezoelectric constant d33 and Td of BNLKT4-20 and BNLKT8-20 were 0.603, 176 pC/N, and 171degC, and 0.590, 190 pC/N, and 115degC, respectively. In addition, the relationship between d33 and Td of tetragonal side and rhombohedral side for BNLKT4-100z and BNLKT8-100z were presented. Considering both high Td and high d33, the tetragonal side of BNLKT4-100z is thought to be the superior composition. The d33 and Td of BNLKT4-28 were 135 pC/N and 218degC, respectively. Moreover, this study revealed that the variation of Td is related to the variation of lattice distortion such as rhombohedrality 90-alpha and tetragonality c/a.