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1.
综述了Bi0.5Na0.5TiO3-BaTiO3系和Bi0.5Na0.5TiO3-Bi0.5K0.5TiO3系无铅压电陶瓷的最新研究进展.总结了各种添加剂对这两种无铅压电陶瓷体系压电性能的影响机理和规律,介绍了当前以各种工艺对其微观结构和压电性能进行改进的研究成果,并展望了这两种无铅压电陶瓷体系的发展趋势. 相似文献
2.
采用传统的干压成型法制备了Na0.5Bi0.5TiO3-K0.5Bi0.5TiO3无铅压电陶瓷,研究了不同K0.5Bi0.5TiO3含量对Na0.5Bi0.5TiO3-K0.5Bi0.5TiO3陶瓷的微观结构与电性能的影响规律.结果表明,Na0.5Bi0.5TiO3-K0.5Bi0.5TiO3无铅压电陶瓷随K0.5Bi0.5TiO3含量增加,晶格常数增大,密度减小,晶粒尺寸减小,压电常数先增大后减小,介电常数增大,介电损耗增加,机械品质因数下降,而居里温度不断升高,在200℃附近存在由铁电相向反铁电相转变的一个相变点,组分为0.84 Na0.5Bi0.5TiO3-0.16 K0.5Bi0.5TiO3的陶瓷位于准同型相界附近,具有最佳的压电性能. 相似文献
3.
研究了(Na1-xKx)0.5Bi0.5TiO3体系x分别为0、0.08、0.16和0.20时陶瓷不同频率下的介电温谱,发现材料为弛豫型铁电体,材料的介电谱在室温到500℃的温度范围内存在一个介电常数-温度"台阶",一个介电常数-温度峰和一个介电损耗-温度峰,通过分析陶瓷不同温度下的电滞回线验证陶瓷在升温过程中产生了铁电-反铁电-顺电相变,采用铁电体成分起伏理论和内电场理论解释了这类弛豫型铁电体相变的原因. 相似文献
4.
New (1 – x ? y)Bi 0.5Na 0.5TiO 3- xY 0.5Na 0.5TiO 3- yBaTiO 3 lead-free ceramics have been prepared by a conventional ceramic fabrication technique, and their structure and electrical properties have been studied. A morphotropic phase boundary (MPB) of rhombohedral and tetragonal phases is formed at 0.04 < y < 0.10. As compared to pure Bi 0.5Na 0.5TiO 3 ceramic, the partial substitutions of Y 3+ for Bi 3+ and Ba 2+ for (Bi 0.5Na 0.5) 2+ in the A-sites of Bi 0.5Na 0.5TiO 3 lower effectively the coercive field E c and increase the remanent polarization P r of the ceramics. Because of low E c, large P r and the MPB, the ceramics with x = 0–0.02 and y = 0.06 exhibit the optimum piezoelectric properties: d 33 = 155–159 pC/N and k p = 28.8–36.7%. The temperature dependences of dielectric properties of the ceramics show relaxor-like behaviors. The ferroelectric properties at different temperature suggest that the ceramics may contain both the polar and non-polar regions near/above T d. 相似文献
5.
The elastic constant matrix at room temperature and the temperature dependence of C
11 constant (30–400°C) of Na 0.5Bi 0.5TiO 3 single crystal have been measured for the first time. The anomaly at the temperature, which corresponds to disappearing of ferroelectric state (200°C), and broad minimum about temperature, which correlates to maximum of electric permittivity (320°C), has been revealed. It has been concluded, that this minimum can be dynamic effect and does not indicate of the structural phase transition. Also the use of NBT for device applications has been indicated. 相似文献
6.
Gd 2O 3 (0–0.8 wt.%)-doped 0.82Bi 0.5Na 0.5TiO 3–0.18Bi 0.5K 0.5TiO 3 (BNKT18) lead-free piezoelectric ceramics were synthesized by a conventional solid-state process. The effects of Gd 2O 3 on the microstructure, the dielectric, ferroelectric and piezoelectric properties were investigated. X-ray diffraction (XRD) data shows that Gd 2O 3 in an amount of 0.2–0.8 wt.% can diffuse into the lattice of BNKT18 ceramics and form a pure perovskite phase. Scanning electron microscope (SEM) images indicate that the grain size of BNKT18 ceramics decreases with the increase of Gd 2O 3 content; in addition, all the modified ceramics have a clear grain boundary and a uniformly distributed grain size. At room temperature, the ferroelectric and piezoelectric properties of the BNKT18 ceramics have been improved with the addition of Gd 2O 3, and the BNKT18 ceramics doped with 0.4 wt.% Gd 2O 3 have the highest piezoelectric constant ( d33 = 137 pC/N), highest relative dielectric constant ( εr = 1023) and lower dissipation factor (tan δ = 0.044) at a frequency of 10 kHz. The BNKT18 ceramics doped with 0.2 wt.% Gd 2O 3 have the highest planar coupling factor ( kp = 0.2463). 相似文献
9.
Lead-free piezoelectric ceramics with compositions around the morphotropic phase boundary (MPB) x(Na0.5Bi0.5)TiO3-y(K0.5Bi0.5)TiO3-zBaTiO3 [x + y + z = 1; y:z = 2:1] were synthesized using conventional, solid-state processing. Dielectric maximum temperatures of 280 degrees C and 262 degrees C were found for tetragonal 0.79(Na0.5Bi0.5)TiO3-0.14(K0.5Bi0.5)TiO3-0.07BaTiO3 (BNBK79) and MPB composition 0.88(Na0.5Bi0.5)TiO3-0.08(K0.5Bi0.5)TiO3-0.04BaTiO3 (BNBK88), with depolarization temperatures of 224 degrees C and 162 degrees C, respectively. Piezoelectric coefficients d33 were found to be 135 pC/N and 170 pC/N for BNBK79 and BNBK88, and the piezoelectric d31 was determined to be -37 pC/N and -51 pC/N, demonstrating strong anisotropy. Coercive field values were found to be 37 kV/cm and 29 kV/cm for BNBK79 and BNBK88, respectively. The remanent polarization of BNBK88 (approximately 40 microC/cm2) was larger than that of BNBK79 (approximately 29 microC/cm2). The piezoelectric, electromechanical, and high-field strain behaviors also were studied as a function of temperature and discussed. 相似文献
10.
铁电薄膜材料、集成铁电器件以及与之相关的物理问题,多年来一直是物理学(特别是电介质物理学)、材料科学与工程、微电子与光电子等领域的科学技术人员所关注的重要问题之一。重点介绍了钛酸铋钠系列铁电薄膜及其掺杂的研究,同时介绍了笔者对钛酸铋钠薄膜掺杂钙、锶、钡的一系列研究工作。 相似文献
11.
合成了具有单一钙钛矿结构的(Nao.5Bi0.5)1-xBaxTiO3超细粉料,研究其陶瓷的压电性能.结果表明,柠檬酸与金属离子的摩尔比(C/Mn )和前驱体溶液的pH值是影响溶胶与凝胶形成的主要因素,凝胶在600℃下热处理1 h后可形成单一钙钛矿结构的(Nao.5Bi0.5)1-xBaxTiO3超细粉料.用柠檬酸盐法合成粉料的颗粒细小、化学成分均匀,有利于提高(Na0 5Bi0.5)1-xBaxTiO3陶瓷的压电性能.在准同质相界附近的组分存在较多的自发极化取向,因而表现出优良的压电性能.x=0.06时,柠檬酸盐法制备陶瓷样品的压电常数d33达到180 pC/N. 相似文献
12.
Er 2O 3 (0–0.8 wt.%)-doped 0.82Bi 0.5Na 0.5TiO 3–0.18Bi 0.5K 0.5TiO 3 (BNKT18) lead-free piezoelectric ceramics were synthesized by a conventional solid-state reaction method. The effects of Er 2O 3 on the microstructure and electrical properties were investigated. X-ray diffraction (XRD) data shows that Er 2O 3 in an amount of 0.2–0.8 wt.% can diffuse into the lattice of the BNKT18 ceramics and form the pure perovskite phase. Scanning electron microscope (SEM) images indicate that the grain sizes of BNKT18 ceramics decrease with the increase of Er 2O 3 content; in addition, the modified ceramics have the clear grain boundary and a uniformly distributed grain size. At room temperature, the electrical properties of the BNKT18 ceramics have been improved with the addition of Er 2O 3, and the BNKT18 ceramics doped with 0.6 wt.% Er 2O 3 have the highest piezoelectric constant ( d33 = 138 pC/N), the highest planar coupling factor ( kp = 0.2382), the highest remnant polarization ( Pr = 25.2 μC/cm 2), the higher relative dielectric constant ( εr = 936) and lower dissipation factor (tan δ = 0.047) at a frequency of 10 kHz. Moreover, the Tm and Td of the samples increase with the addition of Er 2O 3. 相似文献
13.
We have investigated the voltage-tunable characteristics of the Na(0.5)Bi(0.5)TiO(3)-NaTaO(3) homogeneity region, for which samples were prepared using a conventional solid-state reaction. The highest value of the relative tunability (n(r)) was obtained for the sample with 5 mol% of NaTaO(3), i.e., 47% at 1 MHz and a 70 kV/cm dc bias field. This sample also showed the highest value of the dielectric losses (tan delta) and temperature coefficient of the dielectric constant (tau(epsilon)), i.e., 0.05 and 4478 ppm/K, respectively. As the concentration of NaTaO(3) increased up to 90 mol% n(r), tan delta, and tau(epsilon) gradually decreased toward 22%, 0.0002 and -899 ppm/K, respectively. The dielectric constant of the samples varied in a similar manner between 662 and 130. At microwave frequencies, the dielectric losses of the samples substantially increased due to their relaxor-type nature. The lowest value was obtained for the samples with 90 mol% of NaTaO(3), i.e., 0.002. The tunable characteristics of the samples are related to the ferroelectric and dielectric properties, and it appears that the dielectric tunability of the Na(0.5)Bi(0.5)TiO(3)-NaTaO(3) system originates from its relaxor-type behavior. 相似文献
14.
In this paper, room temperature multiferroic behaviour in Ni (Nickel)-doped NBT (Na0.5Bi0.5TiO3) ceramics synthesized using solid state reaction technique have been investigated. Structural, dielectric, ferroelectric, magnetic and magneto-dielectric properties were consistently probed with the increment in transition metal doping. XRD peaks were indexed for the monoclinic Cc phase. SEM micrographs clearly depicted the reduction of grain size with addition of Ni content. Ferroelectric polarization (P) vs applied electric field (E) hysteresis curves shows an increase in lossy behaviour with an increase in Ni content. The room temperature magnetization (M) vs applied magnetic field (H) curves depict the weak ferromagnetic ordering on increasing the Ni doping. Enhanced magneto-dielectric change of 1.26% was observed in 25% Ni-doped NBT ceramic, which may be useful in the development of novel non-volatile lead-free multiferroic memory devices. 相似文献
15.
目的 在Na0.5Bi0.5TiO3基陶瓷材料中诱导缺陷来提高其电致伸缩性能,在室温下获得性能优异的电致伸缩材料,该材料可用于包装机械物料供给微振动器的研发。方法 利用传统固相合成法制备0.7(Bi0.5Na0.5)Ti0.9Mn0.1O3?0.3Sr(1?3x/2)Bix□x/2TiO3(NBT?SBxT?Mn)陶瓷。通过掺杂Sr(1?3x/2)Bix□x/2TiO3,在陶瓷中形成VA?VO局部缺陷,获得具有极性纳米微区的非极性相结构。同时,通过掺杂MnO在陶瓷中形成Mn?VO缺陷偶极子,获得滞后小的电致伸缩应变。结果 所制备的样品均表现出极性纳米微区的非极性相结构和弥散度高于1.80的典型弛豫特征。随着x的增加,氧空位的含量先降低后明显增大。氧空位含量的降低表明在NBT?SBxT?Mn陶瓷中形成了Mn?VO缺陷偶极子。在VA?VO局部缺陷、Mn?VO缺陷偶极子、较高弛豫性及形成的极性纳米微区的共同作用下,组分x=0.07样品的电致伸缩系数高达0.036 m4/C2,性能优异。结论 通过在NBT基陶瓷材料中诱导缺陷能够有效改善其电致伸缩性能。 相似文献
16.
研究了Na 0.5Bi 0.5TiO 3和(Na 0.5Bi 0.5) 0.94Ba 0.06TiO 3陶瓷的电滞回线、压电性能和热滞现象·得到(Na 0.5Bi 0.5) 0.94 Ba 0.06TiO 3陶瓷的剩余极化P r=19uC/cm 2、矫顽场E c=4.7kV/mm.发现用适量的Ba 2+取代(Na 0.5Bi 0.5) 2+尽管压电性能有所提高,但同时使得材料的温度稳定性大大降低. 相似文献
17.
目的 利用SrTiO3调控Na0.5Bi0.5TiO3−BaTiO3−SrTiO3(NBT−BT−ST)三元系陶瓷的相结构,在室温下获得性能优异的电致伸缩材料,该材料可用于包装机械物料供给微振动器的研发。方法 采用传统固相合成法制备(1− x)[0.94NBT−0.06BT]− xST陶瓷。在分析(1− x)[0.94NBT−0.06BT]− xST陶瓷相图的基础上,阐述不同相区应变的来源,并系统研究弛豫相区陶瓷铁电、应变和电致伸缩性能等。结果 随着ST含量的增加,(1− x)[0.94NBT−0.06BT]− xST陶瓷的相结构由三方相、四方相两相共存→四方铁电相→铁电相、弛豫相共存→弛豫相。三方、四方两相共存区陶瓷的应变主要来源于晶格变形和非180 o畴转向。铁电、弛豫两相共存区陶瓷的应变主要来源于电场引发弛豫相和铁电相的相变。弛豫相区陶瓷的应变主要来源于样品晶格本征变形产生的电致伸缩效应。在弛豫相区,随着ST含量的增大,(1− x)[0.94NBT−0.06BT]− xST陶瓷的弛豫性增强,电滞回线逐渐变瘦,应变和滞后性均出现不同程度的降低,其中, x=0.40的样品在电场强度60 kV/cm下的应变滞后性降至7.8%,表现出典型的电致伸缩特征。在较强的弛豫性和形成纳米极性微区的作用下,在组分 x=0.40时陶瓷在电场强度50 kV/cm下的电致伸缩系数高达0.021 3 m 4/C 2。结论 通过ST调控NBT基陶瓷的相结构,在弛豫相区能够有效地改善其电致伸缩性能。利用该技术制备的陶瓷电致伸缩材料可为包装机械物料供给微驱动器的研发和改进提供技术支持。 相似文献
18.
综述了(Na0.5Bi0.5)Tio3(简写为NBT)基无铅压电陶瓷的发展现状,特性及影响因素,用分子轨道理论解释了NBT强铁电性的成因,对研究较多的三个体系:NBT-ATiO3(A=Ca,Sr,Ba),NBT-BNbO3(B=Na,K)和NBT-Ln掺杂体系给予了概括介绍,内容包括成分配比,性能和应用,并提出了NBT基无铅压电陶瓷的设计原则。 相似文献
19.
随着人们环保意识的增强,作为环境友好型的无铅压电陶瓷典型代表Bi0.5Na0.5TiO3基压电陶瓷已成为压电陶瓷领域研发的热点材料之一.结合目前有关报道,着重介绍了近年来国内外该陶瓷在相关电子器件中的应用,并展望了BNT基无铅压电陶瓷应用的发展趋势. 相似文献
20.
AbstractA novel method for synthesizing Na 0.5Bi 0.5TiO 3 (BNT) anisotropic particles with grain orientation is reported. Anisotropically shaped particles of BNT were prepared by conversion of Na 0.5Bi 4.5Ti 4O 15 (NBT15) single crystals. Platelet NBT15 was produced by molten-salt synthesis. They were converted to BNT by second molten-salt synthesis at 800—1200 ?C. NBT15 single-crystal platelets were transformed into platelet particles of polycrystalline BNT. The reaction is topotaxial, those recrystallized BNT were oriented with (h 0 0) plane parallel to the platelet. The use of converted BNT particles as seed was confirmed by performing templated grain growth (TGG) of BNT with 5% grain-oriented, anisotropic particles of BNT. 相似文献
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