Structure, ferroelectric and piezoelectric properties of (Bi0.98−xLa0.02Na1−x)0.5BaxTiO3 lead-free ceramics
Structure, ferroelectric and piezoelectric properties of (Bi0.98−xLa0.02Na1−x)0.5BaxTiO3 lead-free ceramics
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DOI：
10.1007/s00339-009-5189-z
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发表时间：
2009-03
期刊：
影响因子：
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通讯作者：
Dunmin Lin;K. Kwok
中科院分区：
文献类型：
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作者：
Dunmin Lin;K. Kwok
采用常规烧结工艺制备了无铅（Bi 0.98-xLa 0.02Na 1-x）0.5 μ m TiO 3陶瓷，并对其结构、铁电和压电性能进行了研究。X射线衍射结果表明，La 2+和Ba 2+扩散到Bi 0.5Na 0.5TiO 3晶格中形成了纯钙钛矿结构的新固溶体，在0.04<x<0.10处存在准同型相界（MPB）。与纯Bi 0.5Na 0.5TiO 3陶瓷相比，（Bi 0.98 − xLa 0.02Na 1 −x）0.5 μ m TiO 3陶瓷具有更小的矫顽场E_c和更大的反射极化Pr。由于低的Ec（3.38 kV/mm）、大的Pr（46.2 μC/cm ~ 2）和四方相MPB的形成，在x =0.06：d33=181 pC/N和kp = 36.3%时，陶瓷的压电性能得到显著提高。退极化温度T在MPB附近达到最小值。该陶瓷表现出驰豫特征，这可能是12重配位点阳离子无序的结果。铁电和介电性能的温度依赖性表明，陶瓷可能包含极性和非极性区域在温度高于Td。
Lead-free (Bi0.98−xLa0.02Na1−x)0.5BaxTiO3ceramics have been prepared by an ordinary sintering technique and their structure, ferroelectric and piezoelectric properties have been studied. The results of X-ray diffraction show that La2+and Ba2+diffuse into the Bi0.5Na0.5TiO3lattices to form a new solid solution with a pure perovskite structure, and a morphotropic phase boundary (MPB) exists at 0.04<x<0.10. Compared with pure Bi0.5Na0.5TiO3ceramics, the (Bi0.98−xLa0.02Na1−x)0.5BaxTiO3ceramics possess much smaller coercive fieldEcand larger remanent polarizationPr. Because of the lowEc(3.38 kV/mm), largePr(46.2 μC/cm2) and the formation of the MPB of rhombohedral and tetragonal phases, the piezoelectric properties of the ceramics are significantly enhanced atx=0.06:d33=181 pC/N andkp=36.3%. The depolarization temperatureTdreaches a minimum value near the MPB. The ceramics exhibit relaxor characteristic, which is probably a result from the cation disordering in the 12-fold coordination sites. The temperature dependences of the ferroelectric and dielectric properties suggest that the ceramics may contain both polar and non-polar regions at the temperatures aboveTd.