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排序方式: 共有2004条查询结果,搜索用时 31 毫秒
31.
采用柠檬酸盐法制备铌酸锂铁电薄膜。探讨了柠檬酸(CA)和乙二醇(EG)的用量、pH和水浴温度等工艺参数对溶胶性能的影响。采用XRD和TG—DTA研究了铌酸锂(LiNbO3)晶相的形成过程,用XRD和AFM对所制得薄膜的物相组成和表面形貌进行了表征。结果表明,当前驱体溶胶的pH为7.5,水浴温度大于80℃,n(CA):n(Li+Nb)=3:1,n(CA):n(EG)=1:2时,可以获得稳定性好的溶胶。薄膜经缓慢升温至800℃热处理,可以获得单相、表面光滑、晶粒大小均匀、晶粒大小为70nm的LiNbO3铁电薄膜。 相似文献
32.
Natália F. C. Vargas Mahmoud S. Alkathy José A. Eiras Valmor Roberto Mastelaro Manuel H. Lente 《Journal of the American Ceramic Society》2021,104(6):2600-2609
In this work, the influence of the sintering temperature on the physical properties of (Pb0.8La0.2)(Ti0.9Ni0.1)O3 (PLT-Ni) ceramics is reported. The experimental data revealed that the energy band gap of PLT-Ni ceramics could be tailored from approximately 2.7 to 2.0 eV by changing the sintering temperature from 1100°C to 1250°C. It is demonstrated that the simple substitution of Ti4+ by Ni2+ cations is effective to decrease the intrinsic band gap while increasing the tetragonality factor and the spontaneous polarization. However, the additional red-shift observed in the absorption edge of the PLT-Ni with increasing the sintering temperature was associated with a continuous increase in the oxygen vacancies () amount. It is believed that the impact of the creation of these thermally induced is manifold. The presence of and Ni2+ ions generate the Ni2+- defect-pairs that promoted both a decrease in the intrinsic band gap and an additional increase of the tetragonality factor, consequently, increasing the spontaneous polarization. The creation of Ni2+- defects also changed the local symmetry of Ni2+ ions from octahedral to a square pyramid, thus lifting the degeneracy of the Ni2+ 3d orbitals. With the increase in the sintering temperature, lower-energy absorbing intraband states were also formed due to an excess of , being responsible for an add-on shoulder in the absorption edge, extending the light absorption curve to longer wavelengths and leading to an additional absorption in “all investigated” spectrum as well. 相似文献
33.
通过电滞回线测试,探讨了xPb(Mn1/3Sb2/3)0.05(Zr1/2Ti1/2)0.95O3(1-x)Pb(Zn1/3Nb2/3)0.28(Zr1/2Ti1/2)0.72O3[xPMnS-(1-x)PZN]陶瓷的铁电性能及铁电相变特性.同时研究了Ba2 取代Pb2 对材料铁电性能的影响.结果表明;三方相含量较高的0.2PMnS-0.8PZN陶瓷具有较高的矫顽场和较大的剩余极化强度;四方相含量较高的0.5PMnS-0.5PZN和0.6PMnS-0.4PZN陶瓷具有较低的矫顽场和较小的剩余极化强度,Ba2 取代使三方相含量增加,铁电性能明显提高. 相似文献
34.
4′ 羟基联苯 4 甲酸与甲醇反应,合成了4′ 羟基联苯 4 甲酸甲酯。后者与1,6 二溴己烷反应合成了目标化合物4′ (6 溴己氧基)联苯 4 甲酸甲酯,反应工艺条件为:以无水乙醇为溶剂,n(4′ 羟基联苯 4 甲酸甲酯)∶n(碳酸钾)∶n(1,6 二溴己烷)=1∶1 5∶3,80℃反应8h,收率达60 8%。两步总收率57 6%。目标化合物经IR,1HNMR和元素分析确证了分子结构。 相似文献
35.
Zhaoxia Zhou Ian M. Reaney Peiyi Wang David Hind Jinda Khemprasit Steven J. Milne 《Journal of the American Ceramic Society》2004,87(2):221-226
Integrated lead zirconate titanate thin films deposited on Pt/Ti/SiO2 /Si substrates using a novel triol-based route were characterized using X-ray diffraction and transmission electron microscopy. Crack-free single-layer PZT films of up to 200 nm thick were prepared by triol-based sol–gel processing onto Pt/Ti/SiO2 /Si substrates. Films ∼75 nm thick exhibited a microstructure free of pores and second phase. As film thickness increased, film texture changed from {100} to {111} perovskite. Essentially, single-phase multilayer films could be prepared by the deposition and pyrolysis of several 75 nm layers, followed by a single crystallization step. The influence of heat-treatment schedule on the microstructure and orientation of the multilayer films is discussed. Comparison has been made between multilayer films prepared using the triol-based sol and an inverted mixing order/acetic acid-based sol. 相似文献
36.
是在热力学唯象理论的框架下,研究由两种铁电材料组成的铁电双层膜系统的极化性质.通过引入的两个参量:参量(描述铁电双层膜系统中两种铁电体的物理性能差异)和参量(描述铁电双层膜系统两种铁电体相变温度的差异),研究了不同温度和不同界面耦合系数条件下,铁电双层膜系统平均极化随这两个参量的变化情况.研究表明:参量增大时,铁电双层膜系统的平均极化随之增大.当取固定值时,平均极化随界面耦合系数增大而增大;随着温度t、参量的增大而减小.参量增大时,铁电双层膜系统的平均极化减小.当参量取固定值时,平均极化随着温度t的增大而减小;随着参量、界面耦合系数的增大而增大. 相似文献
37.
Ba0.85Ca0.15(Ti0.9Zr0.1)1-xFexO3 (x = 0, 0.5, and 1%) ceramics were studied for piezocatalysis, photocatalysis, and pyrocatalysis using dye degradation in the simulated wastewater. The effect of electrical poling was also performed and found a significant impact of poling on all three catalytic reactions. Fe decreased the optical bandgap of Ba0.85Ca0.15Ti0.9Zr0.1O3 (BCZTO) to the visible region. Bandgap for x = 0, 0.005, and 0.01 was found to be 3.14 eV, 2.75 eV, and 2.61 eV, respectively. Interestingly, visible light photocatalytic activity was observed after Fe inclusion in BCZTO lattice. These compositions have also demonstrated dye degradation under ultrasonication (piezocatalytsis) and during temporal temperature change (pyrocatalysis). Results indicate promising multicatalysis in BCZTO ceramics which can be tuned using Fe substitution. 相似文献
38.
Jin Xu Tingting Zang Ding Du Sandeep Kumar Moolchand Sharma Rahul Vaish 《Journal of the American Ceramic Society》2021,104(4):1661-1668
The BaTiO3 powder was prepared via a solid-state reaction route. It was studied for the degradation of bacterial cells, dye, and pharmaceuticals waste using ultrasonically driven piezocatalytic effect. The bacterial catalytic behavior of poled BaTiO3 was remarkably increased during ultrasonication (10% E coli survival in 60 minutes). The structural damages were illustrated using scanning electron micrographs of bacterial cells which demonstrated morphological manifestations under different conditions. Methylene blue (MB dye), ciprofloxacin and diclofenac were also cleaned using the piezocatalytic effect associated with the poled BaTiO3 powder. Around 92, 85, and 78% of degradations were observed within 150 minutes duration for methylene blue, ciprofloxacin, and diclofenac, respectively. 相似文献
39.
40.
通过在硅油中加恒电场实验,研究了PZT-5H铁电陶瓷Vickers压痕裂纹的扩展行为,探讨了电场、残余应力以及介质间的耦合作用.结果表明,残余应力不足以使压痕裂纹在硅油中发生滞后扩展,只有外加恒电场E>0.2 kV/cm,电场、残余应力和介质的耦合才能使压痕裂纹在经过一个孕育期tp后发生滞后扩展.由于有效应力强度因子随裂纹扩展而下降,故压痕裂纹扩展10-30 μm后就将止裂.压痕裂纹在硅油中滞后扩展的门槛电场强度EDp=0.2 kV/cm.如外加电场大于临界电场Ep=5.25 kV/cm,电场和残余应力的耦合可使压痕裂纹瞬时扩展;保持恒电场,裂纹能继续扩展,然后止裂.如外加电场大于12.6 kV/cm,不需要残余应力协助,电致裂纹也能在光滑试样上形核、长大、连接,导致试样断裂.试样发生电致滞后断裂的门槛电场EDF=12.6 kV/cm,发生瞬时断裂的临界电场EF=19.1 kV/cm. 相似文献