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Bi0.5Na0.5TiO3基无铅压电陶瓷设计与制备研究的新进展 总被引:1,自引:0,他引:1
综述了Bi0.5Na0.5TiO3(BNW)基无铅压电陶瓷体系研究的最新进展,介绍了BNT基无铅压电陶瓷的设计方法及其制备技术.用自洽场离散变分法(self-consult charge-discrete variation-Xa,SCC-DV-Xa)等计算方法可为设计新型BNT基陶瓷提供重要的理论指导.用湿化学法,包括:溶胶-凝胶法、柠檬酸盐法、水热法等,可以合成BNT基纳米粉体,该类方法制备的BNT基粉体具有良好烧结活性,利于致密化烧结,使材料电性能得到改善.用模板晶粒生长技术可获得晶粒生长定向程度很高的BNT基压电陶瓷材料,进而提高材料在特定方向的压电性能. 相似文献
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综述了无铅压电陶瓷研究开发的相关进展,着重介绍了BaTiO3基无铅压电陶瓷、Bi1/2Na1/2TiO3(BNT)基无铅压电陶瓷、NaNbO3基无铅压电陶瓷、铋层状结构无铅压电陶瓷及钨青铜结构无铅压电陶瓷等不同陶瓷种类的相关体系、制备方法及压电铁电性能,并对其应用及发展前景进行了展望。 相似文献
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无铅压电陶瓷的开发与应用是当今压电陶瓷发展的必然趋势,本文综合分析了无铅压电陶瓷的研究背景,给出了钙钛矿型无铅压电陶瓷的主要体系,包括钛酸钡基无铅压电陶瓷、BNT基无铅压电陶瓷,分析比较了其性能及研究现状。 相似文献
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Astri Bjørnetun Haugen Gerhard Henning Olsen Francesco Madaro Maxim I. Morozov Goknur Tutuncu Jacob L. Jones Tor Grande Mari‐Ann Einarsrud 《Journal of the American Ceramic Society》2014,97(12):3818-3825
Improved performance by texturing has become attractive in the field of lead‐free ferroelectrics, but the effect depends heavily on the degree of texture, type of preferred orientation, and whether the material is a rotator or extender ferroelectric. Here, we report on successful texturing of K0.5Na0.5NbO3 (KNN) ceramics by alignment of needlelike KNN templates in a matrix of KNN powder using tape casting. Homotemplated grain growth of the needles was confirmed during sintering, resulting in a high degree of texture parallel to the tape casting direction (TCD) and the aligned needles. The texture significantly improved the piezoelectric response parallel to the tape cast direction, corresponding to the direction of the strongest <001>pc orientation, while the response normal to the tape cast plane was lower than for a nontextured KNN. In situ X‐ray diffraction during electric field application revealed that non‐180° domain reorientation was enhanced by an order of magnitude in the TCD, compared to the direction normal to the tape cast plane and in the nontextured ceramic. The effect of texture in KNN is discussed with respect to possible rotator ferroelectric properties of KNN. 相似文献
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以SO2 为毒物 ,采用脉冲中毒方法 ,再以CO氧化反应为探针 ,对三元复合氧化物催化剂La0 .5Sr0 .5NiO3 与La0 .5Sr0 .5CuO3 以及四元复合氧化物催化剂La0 .5Sr0 .5Ni0 .5Cu0 .5O3 等三种催化剂样品的抗硫毒能力、失活曲线、中毒催化剂的再生性能以及毒物残留形态等进行了全面考察和对比分析。实验结果表明四元复合氧化物催化剂La0 .5Sr0 .5Ni0 .5Cu0 .5O3 在SO2 毒物含量是 1 2 2×10 -2 mmol时 ,特别是在高温 (≥ 30 0℃ )条件下 ,具有优异的抗硫性能 相似文献
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Ling Li Ji Zhang Rui-Xue Wang Mupeng Zheng Yudong Hou Haibo Zhang Shan-Tao Zhang Mankang Zhu 《Journal of the European Ceramic Society》2019,39(5):1827-1836
(1-x)[0.8Bi0.5Na0.5TiO3-0.2Bi0.5K0.5TiO3]-xBi(Mn0.5Ti0.5)O3 (x = 0–0.06, BNKMT100x) lead-free ferroelectric ceramics were prepared via solid state reaction method. Bi(Mn0.5Ti0.5)O3 induces a structure transition from rhombohedral-tetragonal morphotropic phases to pseudo-cubic phase. Moreover, the wide range of compositions within x = 0.03–0.055 exhibit large strain of 0.31%–0.41% and electrostrictive coefficient of 0.027–0.041 m4/C2. Especially, at x = 0.04, the large strain and electrostrictive coefficient are nearly temperature-independent in the range of 25–100 °C. The impedance analysis shows the large strain and electrostrictive coefficient originate from polar nanoregions response due to the addition of Bi(Mn0.5Ti0.5)O3. 相似文献
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采用固相法制备了(1-x)(Na0.5Bi0.5)TiO3-xBa0.5Sr0.5Nb2O6(0≤x≤1.0%)(简称(1-x)NBT-xBSN)无铅压电陶瓷,研究了不同BSN含量(x=0,0.1%,0.3%,0.5%,0.7%,1.0%,摩尔分数)样品的物相组成、显微结构及电性能.结果表明:所有样品均为纯钙钛矿结构,随掺杂量x的增加,陶瓷的相对密度pr、压电常数d33和机电耦合系数kp均先增大后降低,机械品质因子Qm和退极化温度Td则逐渐下降.该体系陶瓷具有弥散相变特征,弥散指数介于1.6~1.7.当x=0.5%时,陶瓷获得最佳性能:d33=92pC/N,kp=0.164,Qm=89,εr=650,tanδ=5.47%,pr=96.5%. 相似文献
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We present how CdTe0.5Se0.5 cores can be coated with Cd0.5Zn0.5S shells at relatively low temperature (around 200°C) via facile synthesis using organic ammine ligands. The cores were firstly fabricated via a less toxic procedure using CdO, trioctylphosphine (TOP), Se, Te, and trioctylamine. The cores with small sizes (3.2-3.5 nm) revealed green and yellow photoluminescence (PL) and spherical morphologies. Hydrophobic core/shell CdTe0.5Se0.5/Cd0.5Zn0.5S quantum dots (QDs) with tunable PL between green and near-infrared (a maximum PL peak wavelength of 735 nm) were then created through a facile shell coating procedure using trioctylphosphine selenium with cadmium and zinc acetate. The QDs exhibited high PL efficiencies up to 50% because of the formation of a protective Cd0.5Zn0.5S shell on the CdTe0.5Se0.5 core, even though the PL efficiency of the cores is low (≤1%). Namely, the slow growth process of the shell plays an important role for getting high PL efficiencies. The properties of the QDs are largely determined by the properties of CdTe0.5Se0.5 cores and shells preparation conditions such as reaction temperature and time. The core/shell QDs exhibited a small size diameter. For example, the average diameter of the QDs with a PL peak wavelength of 735 nm is 6.1 nm. Small size and tunable bright PL makes the QDs utilizable as bioprobes because the size of QD-based bioprobes is considered as the major limitation for their broad applications in biological imaging. 相似文献
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为了进一步探索合成工艺对钛酸铋钠系无铅材料的结构及介电特性的影响,本文以甘氨酸为燃料,利用固相-燃烧法制备了CeO2掺杂的Bi0.5Na0.5TiO3-Bi0.5K0.5TiO3 (BNKT)陶瓷.XRD表明,在固相合成工艺中引入燃烧法制备BNKT陶瓷,比传统固相法降低预烧温度150 ℃,掺杂的CeO2扩散进入了BNKT钙钛矿的晶格,且当掺杂量为0%~0.3%时,形成纯的钙钛矿相结构;SEM表明,CeO2掺杂使晶粒尺寸趋于平均,对晶粒生长有抑制作用;介电温谱表明,随着CeO2掺杂量增加,介电常数εr和退极化温度Td、相转变温度Tm降低,介电反常峰逐渐弱化,且室温至300 ℃,介电损耗tanδ始终在0.3%以下,并从微结构缺陷空位形成机制角度,结合铁电畴壁运动状态,分析讨论了对材料介电特性的作用规律. 相似文献
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We have measured the Raman spectra of bismuth sodium titanate in its rhombohedral, tetragonal, and cubic phases, with special attention paid to the phase transitions at 584K and 837K (heating). Both transitions appear to be order-disorder and strongly first order, with large thermal hysteresis. The phonon spectra at temperature slightly below the tetragonal phase are remarkably similar to BaTiO3 with A1(To) modes at 130, 269, and 541 cm-1 (compared with 170, 270, 520 cm-1 in BaTiO3) and an E(TO) at 52 cm-1. 相似文献
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Irena Gruszka Antoni Kania Ewa Talik Magdalena Szubka Seweryn Miga Joanna Klimontko Jan Suchanicz 《Journal of the American Ceramic Society》2019,102(3):1296-1308
Ceramics of the perovskite multiferroics PbFe0.5Nb0.5O3 (PFN) and PbFe0.5Ta0.5O3 (PFT) were synthesized from new citrate polymeric precursors. X-ray tests pointed to trace amounts of the pyrochlore phase. SEM studies revealed the heterogeneous grain size distribution for PFN and the homogeneous one for PFT. Dielectric studies pointed to one diffuse T-C phase transition at 378 K for PFN and two diffuse M-T and T-C phase transitions, at 200 and 235 K, for PFT, respectively. X-ray photoelectron spectroscopy studies of PFN reveal that all ions exist in one valence state, however, with two chemical shifts for Pb2+. Two valence states for the majority of ions of PFT seem to be connected with a higher volume fraction of the amorphous grain-boundary phase. The electronic energy band gap for both compounds is approximately 2.8 eV. Two magnetic transitions, ie, from the paramagnetic to the antiferromagnetic phase and then to the spin-glass phase, were observed at 156 and 10 K for PFN, and at 145 and 15 K for PFT, respectively. 相似文献