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1.
The structure, ferroelectric characteristics and piezoelectric properties of (Na 0.5Bi 0.5) 1 − xBa xTiO 3 ( x = 0.04, 0.06, 0.10) ceramics prepared by conventional solid state method were investigated. The influences of poling condition and sintering temperature on the piezoelectric properties of the ceramics were examined. The piezoelectric properties of the ceramics highly depend on poling field and temperature, while no remarkable effect of poling time on the piezoelectric properties was found in the range of 5-25 min. Compared with (Na 0.5Bi 0.5) 0.96Ba 0.04TiO 3 and (Na 0.5Bi 0.5) 0.90Ba 0.10TiO 3, the piezoelectric properties of (Na 0.5Bi 0.5) 0.94Ba 0.06TiO 3 are more sensitive to poling temperature due to the relatively low depolarization temperature. Moderate increase of sintering temperature improved the poling process and piezoelectric properties due to the development of microstructural densification and crystal structure. With respect to sintering behavior and piezoelectric properties, a sintering temperature range of 1130-1160 °C was ascertained for (Na 0.5Bi 0.5) 0.90Ba 0.10TiO 3. 相似文献
2.
(1? x)Bi 0.5Na 0.5TiO 3s (solid-state method)– xBi 0.5Na 0.5TiO 3g (sol–gel method)–0.06BaTiO 3 (0 ≤ x ≤ 1) ceramics were prepared and the effect of powder synthesis conditions on the physical properties of ceramics was investigated. A morphotropic phase boundary was observed in the Bi 0.5Na 0.5TiO 3–0.06BaTiO 3 system. With increasing Bi 0.5Na 0.5TiO 3g content, the maximum value of dielectric constant reduces sharply. The Bi 0.5Na 0.5TiO 3g significantly disrupts the long-range ferroelectric order dominant of the ceramics, which leads to a degradation of the remanent polarization and coercive field. These results may be helpful to further understand and design new Bi 0.5Na 0.5TiO 3-based lead-free piezoelectric ceramics. 相似文献
3.
Plate-like templates for the development of grain oriented microstructures are required for lead-free piezoelectric ceramics with directionality of properties. Plate-like Na 0.5Bi 0.5TiO 3 templates with perovskite structure were synthesized by the Topochemical Microcrystal Conversion (TMC) method from bismuth layer-structured ferroelectric compound Bi 4Ti 3O 12. The TMC-derived NBT templates, with diameters of 5-15 µm and an average thickness of 0.7 µm, maintained the morphology of Bi 4Ti 3O 12 precursors, showing a high degree of preferred pseudocubic < 001> orientation. The Na 0.5Bi 0.5TiO 3 particles prepared could serve as good templates for the preparation of grain oriented lead-free NBT-based piezoelectric ceramics. 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 influences of Er content on the dielectric and photoluminescence performances of Bi 0.5Na 0.5TiO 3- xEr ( x = 0, 0.005, 0.01, 0.015, 0.02, 0.03) ceramics have been investigated. The results show that Bi 0.5Na 0.5TiO 3- xEr ceramics with x = 0.01 Er have maximum values of photoluminescence and piezoelectric properties. A bright green emission at 550 nm and enhanced piezoelectric response are achieved in the ceramic Bi 0.5Na 0.5TiO 3-0.01Er at room temperature. Furthermore, the photoluminescence performance of the ceramics is significantly enhanced by electric poling. 相似文献
6.
The Nb 5+ doped (Bi 0.5Na 0.5)TiO 3 (BNT) ceramics were manufactured by a conventional solid state reaction method. The influence of Nb 5+ doping on the sintering, microstructure and various electrical properties of BNT ceramics was investigated. The results of
X-ray diffraction show that the solubility limit of Nb 5+ in the BNT lattice is less than 3%. Additionally, Nb 5+ doping produces significant effects on the densification and grain growth of BNT ceramics. Various electrical properties
of BNT ceramics are obviously changed with doping a small amount of Nb 5+. The ferroelectric and piezoelectric properties display enhanced values at a low doping level. The formation of A-site vacancies
is considered as the reason for the changed ferroelectric and electromechanical behavior. 相似文献
7.
Y 2O 3 doped lead-free piezoelectric ceramics (Bi 0.5Na 0.5) 0.94Ba 0.06TiO 3 (0-0.7 wt%) were synthesized by the conventional solid state reaction method, and the effect of Y 2O 3 addition on the structure and electrical properties was investigated. X-ray diffraction shows that Y 2O 3 diffuses into the lattice of (Bi 0.5Na 0.5) 0.94Ba 0.06TiO 3 to form a solid solution with a pure perovskite structure. The temperature dependence of dielectric constant of Y 2O 3 doped samples under various frequencies indicates obvious relaxor characteristics different from typical relaxor ferroelectric and the mechanism of the relaxor behavior was discussed. The optimum piezoelectric properties of piezoelectric constant d33 = 137 pC/N and the electromechanical coupling factor kp = 0.30 are obtained at 0.5% and 0.1% Y 2O 3 addition, respectively. 相似文献
8.
In this study, a simple compound (1 ? x)(Bi 0.5Na 0.5)TiO 3– xKNbO 3 ( x = 0 – 0.12) lead-free bulk ceramic was developed for high electric power pulse energy storage applications. The dielectric and ferroelectric properties of the ceramics were measured. The results illustrate that the energy storage density of the ceramics is enhanced by the addition of KNbO 3. The influence of applied electric field, temperature, and fatigue on the energy storage properties of the ceramics was evaluated for the composition-optimized (Bi 0.5Na 0.5)TiO 3–0.1KNbO 3 ceramic. The results demonstrate that (Bi 0.5Na 0.5)TiO 3–0.1KNbO 3 ceramic is a promising lead-free material for high power pulse capacitor applications. The excellent energy storage properties of the (Bi 0.5Na 0.5)TiO 3–0.1KNbO 3 ceramics are ascribed to the reversible relaxor–ferroelectric phase transition induced by the electric field. 相似文献
9.
(001)(pc)-oriented (Na(0.5)Bi(0.5))(0.94)Ba(0.06)TiO(3) (NBBT) lead-free piezoelectric ceramics were fabricated by the screen printing technique using Na(0.5)Bi(0.5)TiO(3) (NBT) templates. The plate-like NBT template particles were synthesized from bismuth layer-structured ferroelectric Bi(4)Ti(3)O(12) (BiT) precursors by the topochemical method. The screen printed NBBT ceramics with 20 wt% NBT templates contained a large fraction of grains aligned with their c-axis normal to the sample surface, giving a Lotgering factor of 0.486. The dielectric and ferroelectric properties of textured NBBT ceramics were anisotropic. Compared with the non-textured NBBT ceramics, the dielectric, ferroelectric, and piezoelectric properties of the textured NBBT ceramics were improved, giving a dielectric constant ?(T)(33)/?(0) of 910, a remnant polarization P(r) of 29.2 μC/cm(2), a coercive field E(c) of 23.5 kV/cm, a piezoelectric coefficient d(33) of 180 pC/N, and a thickness-mode electromechanical coupling coefficient k(t) of 0.485. 相似文献
10.
The 0.935(Bi 0.5Na 0.5) TiO 3 -0.065BaTiO 3 (abbreviated as BNT6.5BT) lead-free ceramics were prepared by conventional solid state sintering technique. The effects of sintering temperature (1150–1200 °C) and poling condition on its piezoelectric properties were examined. Piezoelectric properties like the piezoelectric constant (d 33) and electromechanical factors (k p , k t ) depend on the poling field and poling temperature, whereas different poling times, in the 5–30 min range, were not observed to have any significant effect on the piezoelectric properties. With respect to piezoelectric properties, the chosen sintering temperature range is suitable for BNT6.5BT ceramics. 相似文献
11.
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
12.
The binary lead-free piezoelectric ceramics with the composition of (1 − x)Bi 0.5Na 0.5TiO 3- xBi 0.5K 0.5TiO 3 were synthesized by conventional mixed-oxide method. The phase structure transformed from rhombohedral to tetragonal phase in the range of 0.16 ≤ x ≤ 0.20. The grain sizes varied with increasing the Bi 0.5K 0.5TiO 3 content. Electrical properties of ceramics are significantly influenced by the Bi 0.5K 0.5TiO 3 content. Two phase transitions at Tt (the temperature at which the phase transition from rhombohedral to tetragonal occurs) and Tc (the Curie temperature) were observed in all the ceramics. Adding Bi 0.5K 0.5TiO 3 content caused the variations of Tt and Tc. A diffuse character was proved by the linear fitting of the modified Curie-Weiss law. Besides, the ceramics with homogeneous microstructure and excellent electrical properties were obtained at x = 0.18 and sintered at 1170 °C. The piezoelectric constant d33, the electromechanical coupling factor Kp and the dielectric constant ?r reached 144 pC/N, 0.29 and 893, respectively. The dissipation factor tan δ was 0.037. 相似文献
13.
Lead-free ceramics (Bi 1?xLa x) 0.5(Na 0.84K 0.16) 0.5TiO 3 were prepared by a conventional ceramic technique and the effects of La doping and sintering temperature on the microstructure, ferroelectric and piezoelectric properties of the ceramics were studied. All the ceramics possess a pure perovskite structure and La 3+ diffuses into the Bi 0.5(Na 0.84K 0.16) 0.5TiO 3 lattices to form a solid solution with a rhombohedral symmetry. The addition of La leads to the significant change in the grain morphology and size for the (Bi 1?xLa x) 0.5(Na 0.84K 0.16) 0.5TiO 3 and a number of rod grains with the length of 10–50 μm and the diameter of 1–2 μm are observed in the ceramic with x = 0.04 sintered at 1,140 °C for 2 h. However, as sintering temperature increases to 1,160 °C, the rod grains disappears and the uniform and rectangular grains are observed in the ceramics with x = 0.04. As x increases from 0 to 0.06, the coercive field E c of the ceramics decreases from 4.33 to 2.81 kV/mm and the remanent polarization P r of the ceramics retains the high values of 25.9–27.7 μm/cm 2. The depolarization temperature T d decreases from 154 to 50 °C with x increasing from 0 to 0.10. All the ceramics exhibit the diffusive phase transition at high temperature (280–320 °C). The ceramic with x = 0.04 sintered at 1,150 °C for 2 h exhibit the optimum piezoelectric properties, giving d 33 = 165 pC/N and k p = 32.9 %. The optimum sintering temperature is 1,150 °C at which the improved piezoelectric properties ( d 33 = 165 pC/N and k p = 32.9 %) are obtained. At the high La 3+ level (x = 0.10 and 0.12), the ceramics exhibit weak ferroelectricity ( P r = 13.0–21.2 μm/cm 2) and thus possess poor piezoelectricity ( d 33 = 17–27 pC/N). 相似文献
14.
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
15.
In this study, NaNO 3, Bi(NO 3) 3·5H 2O, Ba(NO 3) 2, Ti(OC 4H 9) 4 and citric acid were successfully introduced to fabricate lead-free piezoelectric (Na 0.5Bi 0.5) 0.94Ba 0.06TiO 3 [NBBT] nanopartical powders by a novel modified sol–gel auto-combustion method. The resultant products were characterized
by the X-ray diffraction analysis and transmission electron microscope method. (Na 0.5Bi 0.5) 0.94Ba 0.06TiO 3 + Mn(NO 3) 2 [NBBTM] can be sintered by the traditional solid-state reaction, and the effects of NBBT doped different amounts of Mn(NO 3) 2 at various sintering temperatures upon phase formation, microstructure as well as piezoelectric properties were further studied.
The experimental results show that it was helpful to control their chemical ingredients and microstructure to prepare nanocrystalline
single phase NBBT powders. Where is the X-ray diffraction result of the corresponding ceramics to prove the existence of the
mixing between rhombohedral and tetragonal phases at the MPB compositions. Doping 0.015 mol% Mn(NO 3) 2 into NBBT at 1,090 °C, piezoelectric constant ( d
33) and relative dielectric constant (ε r) reach the superior value of 159pC/N and 1,304, respectively, and dielectric loss (tan δ) and electromechanical coupling
factor ( K
t) are 2.5% and 65%, respectively. 相似文献
16.
(1 − x)Bi 0.5Na 0.5TiO 3- xBi 0.5K 0.5TiO 3 [BNT-BKT-100 x] thin films have been successfully deposited on Pt/Ti/SiO 2/Si substrates by a sol-gel process together with rapid thermal annealing. A morphotropic phase boundary (MPB) between Bi 0.5Na 0.5TiO 3 and Bi 0.5K 0.5TiO 3 was determined around x ∼ 0.15. Near the MPB, the film exhibits the largest grain size, the highest ε value (360) and the largest Pr value (13.8 μC/cm 2). The BNT-BKT thin film system is expected to be a new and promising candidate for lead-free piezoelectric applications. 相似文献
17.
A new lead-free solid solution of (0.75 ? x)BiFeO 3–0.25BaTiO 3– xBi 0.5(Na 0.8K 0.2) 0.5TiO 3 + 1 mol% MnO 2 has been prepared by a conventional ceramic technique and the effects of Bi 0.5(Na 0.8K 0.2) 0.5TiO 3 and sintering temperature on the structure, ferroelectric and piezoelectric properties of the material have been studied. The ceramics sintered at 960 °C for 2 h possess a pure perovskite structure and no second phases can be detected. After the addition of Bi 0.5(Na 0.8K 0.2) 0.5TiO 3, a morphotropic phase boundary of rhombohedral and orthorhombic phases is formed at x = 0.01. The addition of a small amount of Bi 0.5(Na 0.8K 0.2) 0.5TiO 3 can promote the grain growth, while excess Bi 0.5(Na 0.8K 0.2) 0.5TiO 3 causes an inhibition of grain growth. Sintering temperature has an important influence on the structure and electrical properties of the ceramics. The sintering temperature of 960 °C is a critical temperature to obtain the ceramics with good piezoelectric properties. For the ceramic with x = 0.01 sintered at/above 960 °C located at the morphotropic phase boundary, large grains, good densification, high resistivity and enhanced electrical properties are obtained. 相似文献
18.
The compositional effects on the crystal structure, phase transition, dielectric, ferroelectric and piezoelectric properties
of the (1- x)BaTiO 3- x(Bi 0.5Na 0.5)TiO 3 solid solution ceramics were investigated. After sintering at 1200 °C for 2 h, the ceramics with different content of (Bi 0.5Na 0.5)TiO 3 (BNT) formed single-phase solid solutions with perovskite structure. The lattice constant c/ a ratio of the solid solutions decreased as BNT content increased except that with 20 mol% BNT, which had the largest value
of c/ a ratio for all samples. The second phase transition corresponding to BaTiO 3 (BT) at about 5 °C shifted to low temperature and gradually disappeared as BNT increased. A new secondary phase transition
appeared at 32 °C and 64 °C, respectively, when BNT content was 5 and 14 mol%. The Curie temperature, T
c, shifted in the temperature range between 112 °C and 166 °C, and the remanent polarization, P
r, decreased whereas the coercive field, E
c, increased as the BNT content increased. The relatively high value of piezoelectric coefficient d 33 together with a relatively high Curie temperature and low loss tangent and stable dielectric properties were obtained when
the addition of BNT was 20 mol%. 相似文献
19.
A ferroelectric/multiferroic/ferroelectric sandwiched structure composed by Na 0.5Bi 0.5TiO 3 (NBT) and Bi 1.07Nd 0.03FeO 3 (BNF) with a LaNiO 3 buffer layer were prepared by a sol–gel method. X-ray diffraction indicated the NBT/BNF/NBT films exhibited a pure perovskite structure. The average grain size of BNF and NBT/BNF/NBT were found to be 40 and 80 nm, respectively. Interestingly, the electrical and ferroelectric properties such as leakage current, dielectric constant, and remnant polarization of NBT/BNF/NBT sandwiched layer, were superior to those of BNF single film. However, the saturation magnetization of NBT/BNF/NBT sandwiched layer was reduced. Our work suggested the NBT/BNF/NBT sandwiched layer with improved multiferroic characteristics have a promising application for future information storage devices. 相似文献
20.
(1 − x)Bi 0.5Na 0.5TiO 3– xBi 0.5Li 0.5TiO 3 lead-free ceramics have been prepared by a conventional solid-state reaction method, and their piezoelectric and dielectric
properties have been studied. X-ray diffraction studies reveal that Li + diffuses into the Bi 0.5Na 0.5TiO 3 lattices to form a solid solution with a pure perovskite structure. The addition of Bi 0.5Li 0.5TiO 3 effectively lowers the sintering temperature of the ceramics and greatly assists in the densification of the ceramics. The
ceramic with x = 0.075 possesses the optimum piezoelectric properties: piezoelectric coefficient d
33 = 121 pC/N and planar electromechanical coupling factor k
P = 18.3%. After the partial substitution of Li + for Na + in the A-sites of Bi 0.5Na 0.5TiO 3, the ceramics exhibit more relaxor characteristic, which is probably resulted from the cation disordering in the 12-fold
coordination sites. The depolarization temperature T
d shifts to low temperature with the substitution level x of Li + for Na + increasing. 相似文献
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