D33 Meter Research Articles

Characteristics improvement of Li0.058(K0.480Na0.535)0.966(Nb0.9Ta0.1)O3 lead-free piezoelectric ceramics by LiF additions

In this study, a series of Li0.058(K0.480Na0.535)0.966(Nb0.90Ta0.10)O3 + (x)LiF (x = 0, 0.1, 0.2, 0.3, 0.4, 0.5 wt%) lead-free piezoelectric ceramics were fabricated by a conventional solid-state reaction method. The incorporation of LiF could significantly improve the sintering ability of LKNNT ceramics by reducing the optimal sintering temperature from 1090°C to 1020°C. The crystal phases and micro-structures were analyzed by means of the X-ray diffraction and scanning electronic microscopy, respectively. The impedance analyzer was used to measure the Curie temperature, phase transition point, and electro-mechanical coupling factor. And the d33 meter was used to measure the piezoelectric constants.From the results, due to the addition of 0.2 wt% LiF, uniform and condensed grains can be obtained and hence the sintering temperature can be lowered down. As the contents of LiF increased, the orthorhombic to tetragonal phase transition points TO-T were almost no changed, but the Curie temperature TC decreased from 425°C (x = 0) to 405°C (x = 0.5). And furthermore, the electro-mechanical coupling factor kp and piezoelectric constant d33 were all decreased with increases of LiF contents. Hence, even though the reducing of little amount of piezoelectric characteristics, the LiF addition can improve the sintering ability of the LKNNT ceramics effectively.

The inferences of ZnO additions for LKNNT lead-free piezoelectric ceramics

ABSTRACTBy the conventional solid-state liquid-phase sintering technique, Li0.058(K0.480Na0.535)0.966(Nb0.9Ta0.1)O3 + x wt% ZnO (x = 0, 0.2, 0.4, 0.6, 0.8, 1, 3) lead-free piezoelectric ceramics were fabricated. The addition of ZnO liquid-phase sintering promoters could improve the grain-growth of LKNNT ceramics significantly and its inferences were investigated detailed in this paper. The crystal phases and micro-structures were analyzed by means of the X-ray diffraction and scanning electronic microscopy, respectively. Using the impedance analyzer, the dielectric constant, loss tangent, Curie temperature, phase transition point, and electromechanical coupling factor were measured. And the piezoelectric constants were measured by the d33 meter. Compared to pure LKNNT ceramic (sintered at 1090°C, d33 = 279 pC/N, and kp = 0.46), for x = 0.6 specimen, even though the optimal d33 and kp values were only 272 pC/N and kp = 0.44, but the optimal sintering temperature have been improved from 1090°C to 1020°C successfully.

Comparative face-shear piezoelectric properties of soft and hard PZT ceramics

The face-shear (d36) mode may be the most practical shear mode in piezoelectrics, while theoretically this mode cannot appear in piezoelectric ceramics because of its transversally isotropic symmetry. Recently, we realized piezoelectric coefficient d36 up to 206pC/N in soft PbZr1-xTixO3 (PZT) ceramics via ferroelastic domain engineering [H. C. Miao and F. X. Li, Appl. Phys. Lett. 107, 122902 (2015)]. In this work, we further realized the face-shear mode in both hard and soft PZT ceramics including PZT-4 (hard), PZT-51(soft), and PZT-5H (soft) and investigated the electric properties systematically. The resonance methods are derived to measure the d36 coefficients using both square patches and narrow bar samples, and the obtained values are consistent with that measured by a modified d33 meter previously. For all samples, the pure d36 mode can only appear near the resonance frequency, and the coupled d36-d31 mode dominates off resonance. It is found that both the piezoelectric coefficient d36 and the electromechanical coupling factor k36 of soft PZT ceramics (PZT-5H and PZT-51) are considerably larger than those of the hard PZT ceramics (PZT-4). The obtained d36 of 160–275pC/N, k36 ∼ 0.24, and the mechanical quality factor Q36 of 60–90 in soft PZT ceramics are comparable with the corresponding properties of the d31 mode sample. Therefore, the d36 mode in modified soft PZT ceramics is more promising for industrial applications such as face-shear resonators and shear horizontal wave generators.

The Effect of Niobium Doping on the Electrical Properties of 0.4(Bi0.5K0.5)TiO₃-0.6BiFeO₃ Lead-Free Piezoelectric Ceramics.

Ceramics in the system (Bi0.5K0.5)TiO3-BiFeO3 have good electromechanical properties and temperature stability. However, the high conductivity inherent in BiFeO3-based ceramics complicates measurement of the ferroelectric properties. In the present work, doping with niobium (Nb) is carried out to reduce the conductivity of (Bi0.5K0.5)TiO3-BiFeO3. Powders of composition 0.4(K0.5Bi0.5)Ti1−xNbxO3-0.6BiFe1−xNbxO3 (x = 0, 0.01 and 0.03) are prepared by the mixed oxide method and sintered at 1050 °C for 1 h. The effect of Nb doping on the structure is examined by X-ray diffraction. The microstructure is examined by scanning electron microscopy. The variation in relative permittivity with temperature is measured using an impedance analyzer. Ferroelectric properties are measured at room temperature using a Sawyer Tower circuit. Piezoelectric properties are measured using a d33 meter and a contact type displacement sensor. All the samples have high density, a rhombohedral unit cell and equiaxed, micron-sized grains. All the samples show relaxor-like behavior. Nb doping causes a reduction in conductivity by one to two orders of magnitude at 200 °C. The samples have narrow P-E loops reminiscent of a linear dielectric. The samples all possess bipolar butterfly S-E loops characteristic of a classic ferroelectric material. Nb doping causes a decrease in d33 and Smax/Emax.

Bismuth Titanate Fabricated by Spray-on Deposition and Microwave Sintering For High-Temperature Ultrasonic Transducers.

Thick films of ferroelectric bismuth titanate (Bi4Ti3O12) have been fabricated by spray-on deposition in conjunction with microwave sintering for use as high-temperature ultrasonic transducers. The elastic modulus, density, permittivity, and conductivity of the films were characterized. Electro-mechanical properties of the films were estimated with a commercial d33 meter which gave 16 pC/N. This value is higher than typically reported for bulk bismuth titanate; however, these films withstand higher field strengths during poling which is correlated with higher d33 values. Films were capable of operating at 650 °C for roughly 5 min before depoling and can operate at 600 °C for at least 7 days.

Characterization of Piezoelectric PDMS-Nanoparticle Composites

In this work, the novel fabrication and characterization of elastomeric piezoelectric nanocomposites are explored. Fabrication methods explored herein utilize ball milled barium titanate powder dispersions, along with double walled carbon nanotubes which are dispersed in toluene though the use of an ultrasonic probe. Test devices are then constructed with electrodes made from evaporated gold on polyimide foils and protective dielectrics of pristine PDMS. Two different device construction methods are explored utilizing both direct contact bonding and plasma bonding of the active composite layers to the dielectric/electrode. Test samples are evaluated through the use of a dedicated Berlincourt type piezoelectric d33 meter.

Realization of face-shear piezoelectric coefficient d36 in PZT ceramics via ferroelastic domain engineering

The piezoelectric face-shear (d36) mode may be the most useful shear mode in piezoelectrics, while currently this mode can only exist in single crystals of specific point groups and cut directions. Theoretically, the d36 coefficient vanishes in piezoelectric ceramics because of its transversally isotropic symmetry. In this work, we modified the symmetry of poled PZT ceramics from transversally isotropic to orthogonal through ferroelastic domain switching by applying a high lateral stress along the “2” direction and holding the stress for several hours. After removing the compression, the piezoelectric coefficient d31 is found much larger than d32. Then, by cutting the compressed sample along the Zxt±45° direction, we realized d36 coefficients up to 206pC/N, which is measured by using a modified d33 meter. The obtained large d36 coefficients in PZT ceramics could be very promising for face-shear mode resonators and shear horizontal wave generation in nondestructive testing.

Phase formation and piezoelectric properties of (Pb0·95Ba0·05)(Zr1−xTix)O3 ceramics fabricated by solid state reaction technique

This work studied the crystal structure, microstructure and piezoelectric properties of Lead Barium Zirconate Titanate [(Pb0·95Ba0·05)(Zr1−xTix)O3; (PBZT)] ceramics with 0≤x≤0·50 step 0·05 prepared by the solid state reaction method. PBZT samples were calcined in the range of 900–1000°C for 1 h and sintered at 1200°C for 3 h. The crystal structure, microstructure and piezoelectric properties were analysed by an X-ray diffractometer (XRD), scanning electron microscope (SEM) and d33 meter. It was found that the PBZT ceramics are indexed in the orthorhombic structure for x = 0, the rhombohedral structure for 0·05≤x≤0·30, the coexisting of rhombohedral and tetragonal structure for 0·35≤x≤0·45 and the tetragonal structure for x = 0·50. The average grain size and the density are around 1·20–2·59 μm and 7·52–7·67 g cm−3 respectively. The highest piezoelectric coefficient is 129 pC/N obtained by x = 0·40.

Quelle place pour l’enquête familiale dans la sclérose latérale amyotrophique ?

The impact of microwave sintering on the grain growth, dielectric relaxation and piezoelectric properties of Ba0.82Ca0.18Ti0.90Zr0.10O3 (BCTZ) lead-free ceramics prepared by different methods (solid-state and hydrothermal) was investigated in this study. A combination of XRD, SEM, impedance analyzer, ferroelectric analyzer and d33 meter techniques was used. A higher solid solubility of CaTiO3 in hydrothermal samples was identified from XRD patterns. For the BCTZ prepared by solid state method, high permittivity was obtained, while those prepared by hydrothermal exhibited excellent ferroelectric and piezoelectric properties. In the SEM micrographs, hydrothermal samples showed a relatively smaller and homogeneous grain size (∼100 nm) than solid-state samples (∼800 nm), and nano-ceramics were obtained by this method. A model was established to investigate the differences in grain growth between the two samples during the microwave sintering process. Also, BCTZ ceramics prepared by hydrothermal possessed a better frequency dispersion and thermally activated relaxation.

Impact of fast microwave sintering on the grain growth, dielectric relaxation and piezoelectric properties on Ba0.18Ca0.02Ti0.09Zr0.10O3 lead-free ceramics prepared by different methods

Abstract The impact of microwave sintering on the grain growth, dielectric relaxation and piezoelectric properties of Ba0.82Ca0.18Ti0.90Zr0.10O3 (BCTZ) lead-free ceramics prepared by different methods (solid-state and hydrothermal) was investigated in this study. A combination of XRD, SEM, impedance analyzer, ferroelectric analyzer and d33 meter techniques was used. A higher solid solubility of CaTiO3 in hydrothermal samples was identified from XRD patterns. For the BCTZ prepared by solid state method, high permittivity was obtained, while those prepared by hydrothermal exhibited excellent ferroelectric and piezoelectric properties. In the SEM micrographs, hydrothermal samples showed a relatively smaller and homogeneous grain size (∼100 nm) than solid-state samples (∼800 nm), and nano-ceramics were obtained by this method. A model was established to investigate the differences in grain growth between the two samples during the microwave sintering process. Also, BCTZ ceramics prepared by hydrothermal possessed a better frequency dispersion and thermally activated relaxation.

Effect of Sintering Temperature on Microstructure and Electrical Properties of (1-<i>x</i>)BCZT-<i>x</i>BY Lead-Free Ceramics

Lead-free 0.996(Ba0.85Ca0.15)(Zr0.1Ti0.9)O3-0.004BiYO3 [BCZT-BY] ceramics were prepared by the conventional solid-state sintering method. By means of XRD, SEM, and quasi-static d33 meter etc., the effect of sintering temperature on the microstructure, piezoelectric and dielectric properties of BCZT-BY ceramics were investigated. All the ceramics possess a pure perovskite structure, indicating that Bi3+ and Y3+ are incorporated into Ba0.85Ca0.15Ti0.9Zr0.1O3 lattices to form a solid solution. The results show that the ceramics sintered at 1420°C exhibit the optimum electrical properties: d33 = 130 pC/N, kp = 18.2 %, εr = 4225, and tan δ = 1.95%, respectively.

Effect of Sintering Temperature on Microstructure and Electrical Properties of (Mn, Nb)-Doped BZT-BCT Ceramics

To obtain lead-free 0.5Ba (Zr0.2Ti0.8)O3-0.5(Ba0.7Ca0.3)TiO3 ceramics with excellent microstructure and electrical properties, BZT-BCT ceramics doping Mn4+ and Nb5+ was synthesized follow a conventional solid state reaction route. By means of SEM, XRD, quasi-static d33 meter, the influence of sintering temperature on microstructure, piezoelectric and dielectric properties of BZT-BCT-Mn-Nb ceramics was discussed. The results show that grain size and the dielectric loss of BZT-BCT-Mn-Nb ceramics increase as raising the sintering temperature. When BZT-BCT-Mn-Nb ceramics is sintered at 1380°C, the optimum piezoelectric coefficient and dielectric constant are 264pC/N and 4142, respectively.

Piezoelectric Properties and Domain Configurations of PZT Ceramic with NiO Addition

The effects of nickel oxide addition on the piezoelectric properties and domain configurations of lead zirconate titanate (PZT) ceramic were investigated. PZT with nickel additive having the compositions of (1-x) PZT–xNiO when x = 0, 0.02, 0.04, 0.06, 0.08, and 0.10. The piezoelectric properties (d33 ) of all ceramics were measured at room temperature using d33 meter. The domain structure was observed using piezoresponse force microscopy (PFM). From the results, it could be seen that the properties of PZT ceramic with nickel addition changed significantly with regards to the sintering temperature and nickel content.

Preparation and Piezoelectric Properties of (h00)-Oriented BaTiO3 Ceramics by Tape Casting

(h00)-oriented BaTiO3 ceramics were prepared by tape casting using plate-like BaTiO3 particles as a template. XRD results showed that the degree of orientation of the ceramics is increased from 0.0% to 85.3% by the addition of BaTiO3 template from 0 wt% to 15 wt%, then decreased to 40.7% with further increasing the template to 30wt%. Their piezoelectric properties were measured using a resonance–antiresonance method and d33 meter. It is showed that the piezoelectric properties of oriented samples were increased with increasing degree of orientation. The mass fraction of the template was optimized to achieve improved piezoelectric properties, which was found to be 85.3% with a piezoelectric constant d33 of 320 pC/N.

Molten salt synthesis of (K0.47Na0.47Li0.06)NbO3 lead-free piezoelectric ceramics

(K0.47Na0.47Li0.06)NbO3 (KNLN) lead-free ceramics were prepared by molten salt synthesis (MSS) method using k2CO3-Na2CO3 eutectic mixtures as the flux. The microstructure and piezoelectric properties when sintered at 980–1 030 °C were investigated. The calcined powders were examined by X-ray diffraction. The microstructure of the calcined powders and sintered bodies was observed using a scanning electron microscope (SEM).The piezoelectric constant d33 was measured using a quasi-static piezoelectric d33 meter. The planar coupling coefficient Kp was calculated by resonance-antiresonance method. The experimental data for each sample’s performance indicators were the average values of 8 specimens. The relative densities of sintered specimens are above 97%, and the dielectric loss is below 0.03. It was found that (K0.47Na0.47Li0.06)NbO3 prepared by MSS is compact and lead-free. The piezoelectric constant d33 is 216 pC·N−1 and the planar electromechanical coupling factor Kp is 0.352.

Growth of a New Ordered Langasite Structure Crystal Ca3TaAl3Si2O14

A new ordered piezoelectric single-crystal Ca3TaAl3Si2O14 (CTAS) with langasite structure has been successfully grown with the dimensions of 14−18 mm in diameter and 45 mm in length using the Czochralski technique. The X-ray powder diffraction (XRPD) of the single crystal was performed at room temperature. The lattice parameters were calculated. They are a = 8.060 A, c = 4.909 A, V = 276.19 A3. X-ray fluorescence analysis was used to determine the molar ratio of the ions of the crystal. That is 3.049:0.945:2.975:2:13.875 Ca2+:Ta5+:Al3+:Si4+:O2−. High-resolution X-ray diffraction (HRXRD) results indicate that CTAS crystals are free of low-angle boundaries. The piezoelectric strain constant d11 measured by quasi-static d33 meter is 5.0 pC/N. The transmittance spectrum shows that the as-grown crystal is transparent in the wavelength range of 200−800 nm and the highest transmittance exceeds 86%.

Barium Titanate Piezoelectric Ceramics Manufactured by Two-Step Sintering

Two-step sintering was applied to manufacture fine-grain barium titanate (BaTiO3) piezoelectric ceramics from hydrothermally synthesized 100 nm particles. Scanning electron microscopy (SEM) revealed a small and irregular domain structure in the samples. The sintering condition dependences of density, dielectric constants, and piezoelectric properties were investigated. Under the optimal conditions, dense specimens had an average grain size of approximately 1.6 µm, and showed large dielectric constants and excellent piezoelectric properties. The large piezoelectric constant of d33=460 pC/N was measured using a d33 meter. The Curie and orthorhombic-to-tetragonal phase transition temperatures were 126 and 24 °C, respectively. These results indicated the possibility of applying non-lead-based BaTiO3 ceramics manufactured by a low-cost process to ultrasonic generators, actuators, piezoelectric vibrators, and sensors working at room temperature.

Preparation of [110] Grain Oriented Barium Titanate Ceramics by Templated Grain Growth Method and Their Piezoelectric Properties

[110]-oriented barium titanate (BaTiO3) ceramics were prepared by templated grain growth (TGG) method using [110]-oriented BaTiO3 platelike particles as a template and hydrothermal BaTiO3 sphere particles with different particle sizes as a matrix. The degree of orientation along the [110] direction, F110, was measured using an X-ray diffraction (XRD) pattern by the Lotgering method. To obtain both a high density and a high F110, the preparation conditions were optimized as functions of matrix particle size, volume fraction of the template to the matrix, and sintering temperature. As for the results, BaTiO3-grain-oriented ceramics with a high density of more than 96% were successfully prepared despite various F110 values from 0 to 98%. Scanning electron microscopy (SEM) revealed that their average grain sizes were always approximately 75 µm despite various F110 values and there were no anisotropic microstructures. These grain-oriented BaTiO3 ceramics were poled at 100 °C, and their piezoelectric properties were measured using a resonance–antiresonance method and a piezo d33 meter for d31 and d33 piezoelectric constants. As for the results, the d31 values were almost constant at -50 pC/N despite various F110 values, while the d33 values increased with increasing F110 values, and at around an F110 of 85%, d33 reached a maximum of 788 pC/N.

Characterization of All the Elastic, Piezoelectric, and Dielectric Constants of Tetragonal Pb(Mg1/3Nb2/3)O3–PbTiO3 Single Crystals

Pb(Mg1/3Nb2/3)O3–PbTiO3 (PMN–PT) single crystals have a tetragonal 4 mm symmetry. In this paper, the elastic, piezoelectric, and dielectric constants of PMN–PT single crystals were measured by the resonance method. A total of eleven independent material constants were measured including six elastic compliance constants at a constant electric field, two dielectric constants at constant stress, and three piezoelectric constants d. Four crystal sample sets of different geometries were prepared in order to measure the length–thickness extensional, thickness extensional, length extensional and thickness shear modes of vibrations, respectively. The experimental impedance spectrum of the PMN–PT crystals was compared with a numerical impedance spectrum calculated with the measured material constants. Good agreement between the two spectra confirmed the validity of the characterization method. In addition, the piezoelectric constant d33, which was determined by the resonance method, was also compared with that measured by a commercial d33 meter. This further confirmed the validity of the resonance measurements.

Piezoelectric composite based on the enhanced flexoelectric effects

In this study, a piezoelectric composite is fabricated from a Ba0.67Sr0.33TiO3 (BST) composition and air, and measured at room temperature (24°C) where the BST is in its paraelectric centric phase. The charge separation mechanism is flexoelectricity, driven by the strain gradient introduced by the pyramidal boundary shapes of each BST building unit of the composite. In spite of the macro (millimeter) dimensions of the building units that inhibit a steep strain gradient, the composite is sufficiently active to be measured by using a conventional Berlincourt d33 meter. The measured values are in good agreement with expectation from the earlier measured flexoelectric coefficient μ11 of the BST and the finite element simulation results of the strain gradient in the pyramid BST units.