Piezoelectric Strain Constant D33 Research Articles

Effects of conductive carbon black on PZT/PVDF composites

ABSTRACTIn this paper, the hot-pressing method is selected to prepare piezoelectric vibrator. The effects of different volume ratio of PZT on the dielectric, piezoelectric and mechanical properties of the composites are studied. With the increase of PZT volume fraction in a certain range, the density of the composites, the dielectric constant (ɛ), the dielectric loss (tanδ) and the piezoelectric strain constant (d33) are all increased, while the piezoelectric voltage constant (g33) tends to change smoothly, however, the deformation and compressive yield strength are decreased. The mechanical and piezoelectric properties of the composites are improved after the addition of conductive carbon black particles. The results show that the conductive carbon black can make the structure more compacted and improve the conductivity (σ) of PZT/PVDF composites.

Enhancement of piezoelectricity of tetragonal P4mm SrHfO3 under uniaxial stress: A first principle study

First principle calculations in the framework of density functional theory and density functional perturbation theory within the generalized gradient approximation are used to calculate the ground state polarization, Born effective charges and piezoelectric strain constant d33 of hypothetical tetragonal P4mm SrHfO3. Our results predict the occurrence of piezoelectricity in this hypothetical system. Born effective charges of both Hf and O atoms are much larger than their anticipated nominal charges which show a strong hybridization between Hf and O atomic orbitals. The effect of uniaxial stress along the c-axis on polarization, Born effective charges and piezoelectric strain coefficient d33 are also studied. We found that the polarization will increase as the uniaxial stress raises from negative to positive values. These changes suggest that the uniaxial tensile stress could raise the ferroelectricity, while the uniaxial compressive stress would cancel it. We also found that the piezoelectricity of this system could be improved by applying stress. These results could be significant in the field of lead free piezoelectric materials.

Low-Temperature-Grown KNbO3 Thin Films and Their Application to Piezoelectric Nanogenerators and Self-Powered ReRAM Device.

Amorphous KNbO3 (KN) film containing KN nanocrystals was grown on TiN/SiO2/Si substrate at 350 °C. This KN film showed a dielectric constant (εr) and a piezoelectric strain constant (d33) of 43 and 80 pm/V at 10 V, respectively, owing to the existence of KN nanocrystals. Piezoelectric nanogenerators (PNGs) were fabricated using KN films grown on the TiN/polyimide/poly(ethylene terephthalate) substrates. The PNG fabricated with the KN film grown at 350 °C showed an open-circuit output voltage of 2.5 V and a short-circuit current of 70 nA. The KN film grown at 350 °C exhibited a bipolar resistive switching behavior with good reliability characteristics that can be explained by the formation and rupture of the oxygen vacancy filaments. The KN resistive random access memory device powered by the KN PNG also showed promising resistive switching behavior. Moreover, the KN film shows good biocompatibility. Therefore, the KN film can be used for self-powered biomedical devices.

Origin of enhanced piezoelectric constants of MgNbAlN studied by first-principles calculations

We theoretically investigate the piezoelectric properties of Mg–Nb codoped wurtzite AlN by first-principles calculations and find the following two points. First, doping induces a remarkable softening of elastic constants, especially the diagonal component along the c-axis. This results in the increased piezoelectric strain constant d33, which is about 4.3 times larger than that of wurtzite AlN. Second, the c-axis lattice length increases up to the dopant concentration of around 60 at. %, and then decreases. These features are in excellent agreement with the experimental results previously reported.

Effects of Coupling Agents on the Structure and Electrical Properties of PZT-Poly (Vinylidene Fluoride) Composites

Piezoelectricceramictransducer(PZT)-Poly(vinylidenefluoride)compositeswereprepared by the hot-pressing method. Before addition, PZT particles were firstly modified with two different coupling agents. The micromorphology, microstructure, dielectric properties, and piezoelectric propertiesofthecompositeswerecharacterizedandinvestigated. ResultsindicatedthatPZTparticles were homogeneously dispersed in the poly (vinylidene fluoride) (PVDF) matrix by the addition of coupling agents. The electric properties of PZT-PVDF composites with NDZ-101 were the best. Especially when the volume ratio of the titanate coupling agent NDZ-101 was 1%, the piezoelectric strain constant d33 of PZT-PVDF composites reached maximum value 19.23 pC/N; its relative dielectric constant εr was 67.45; at the same time its dielectric loss tan δ was 0.0766.

The growth and thermal, electrical properties characterization of Ba2TiSi2O8 piezoelectric crystal

Ba2TiSi2O8 (BTS) crystals were successfully grown by the Czochralski method. The raw material ratio was optimized according to the effective segregation coefficient keff of different components in the BTS crystal. The thermal properties of the BTS crystal were systematically studied at elevated temperature, including thermal expansion, specific heat, thermal diffusivity and thermal conductivity. The variations of the thermal expansion coefficients α33 and α11 in the temperature range of 25–185°C were small, whereas those in the temperature range of 185–1000°C were 17.14×10−6/°C and 4.73×10−6/°C, respectively. A strong anisotropic characteristic in the thermal expansion ratio is associated with the lamellar structure of the BTS crystal. The thermal conductivity increased slowly as the temperature rises. The piezoelectric strain constant d33 of the BTS crystal was determined to be 4.5 pC/N at room temperature using a quasi-static d33 meter. The electrical resistivity of the BTS crystal was investigated at temperatures up to 900°C, the resistivity ρr of the BTS Z-cut sample was 2.06×109Ωcm at 800°C, which is three orders of magnitude higher than that of a Ca3TaGa3Si2O14 (langasite-type crystal) X-cut sample (7.15×106Ωcm) at the same temperature. Thermal and electrical properties have shown that BTS crystal is a potential alternative material for the high temperature piezoelectric sensors.

Structural and Piezoelectric Properties of (Na1−xKx)NbO3 Platelets and Their Application for Piezoelectric Nanogenerator

(Na1−xKx)NbO3 (NKN) platelets synthesized at 600°C for 12 h have an Amm2 orthorhombic structure. However, the structure of NKN platelets synthesized at 500°C is a mixture of R3m rhombohedral and Amm2 orthorhombic structures. The formation of a rhombohedral structure is attributed to the presence of OH− and H2O defects in the NKN platelets. The piezoelectric strain constant (d33) of NKN platelets synthesized at 600°C for 12 h is 100 pmV−1, whereas that of NKN platelets synthesized at 500°C is lesser (50 pmV−1) due to the presence of these defects. Piezoelectric nanogenerators (PNGs) are fabricated using composites consisting of NKN platelets and polydimethylsiloxane. A large output voltage of 25 V and output current of 2.7 μA were obtained for the PNG with NKN platelets synthesized at 600°C for 6 h. This PNG shows a high output electrical energy of 3.0 μW at an external load of 5.1 MΩ.

Enhancement of piezoelectric constants induced by cation-substitution and two-dimensional strain effects on ZnO predicted by density functional perturbation theory

Using density functional perturbation theory, we investigated the effect of various substitutional dopant elements and in-plane strain on the piezoelectric properties of ZnO. The piezoelectric stress constant e33 of doped ZnO was found to depend on the formal charge of the substitutional dopant. By decomposing the piezoelectric stress constant e33 into the individual atomic contributions, the change in the piezoelectric properties was found to originate from a change in the coupling between the atomic displacement and the strain. Furthermore, we found that in-plane tensile strain along the a axis, which is specific to the thin film, can enhance the piezoelectric constant of ZnO. A phase transition from wurtzite to h-BN-type structure was found to occur with increasing in-plane tensile. The piezoelectric strain constant d33 was predicted to reach ∼200 pC/N for 2.78 at. % V-substituted ZnO at 5.5% in-plane strain, just before the phase transition. These theoretical results suggest that the piezoelectric constant of ZnO can be enhanced by controlling the in-plane strain via selection of the substrate material and dopant element.

Square cross-section piezoelectric fiber composites: structure and ferroelectric properties

Square cross-section lead zirconate titanate (PZT5) fibers were fabricated by viscous polymer processing. Fibers were perpendicularly arranged in glass tubes and infiltrated with bisphenol-A epoxy resin E51 to form 1–3 composite structures. Phase, micromorphology, mechanical properties and electric properties were identified for fibers and composites. As a result, PZT5 ceramic fibers sintering at high temperature above 1280 °C have pure trigonal perovskite phase and side length of ~300 μm. A brittle broken mechanism was put forward by the linear stress–strain curves of PZT5 fibers. 1–3 composites with 30 % fiber volume fraction demonstrated closed and saturated P–E loops, high remnant polarization P r of 15.94 μC/cm2 and low coercive field E c of 0.91 kV/mm. Moreover, the composites performed high piezoelectric strain constant d 33, piezoelectric voltage constant g 33 and high anisotropy parameters k t/k p. The acoustic impedance Z was about one-third of PZT5 ceramics. The above performances of PZT5 composites showed an excellent application prospect in the fields of ultrasonic medical imaging systems and nondestructive testing.

Matrix influence on the piezoelectric properties of piezoelectric ceramic/polymer composite exhibiting particle alignment

ABSTRACTThis study was addressed to the influence of an electric field strength applied at fabrication process and matrix properties, such as the dielectric constant and the Young's modulus, on “pseudo‐1‐3 piezoelectric ceramic/polymer composite” in order to further enhance the piezoelectricity of that. The pseudo‐1‐3 piezoelectric ceramic/polymer composite consists of linearly ordered piezoelectric ceramic particles in polymer material. Silicone gel, silicone rubber, urethane rubber, and poly‐methyl‐methacrylate, which exhibit different dielectric constants and Young's modulus, were used as matrices to evaluate the matrix influence. The piezoelectricity of the pseudo‐1‐3 piezoelectric ceramic/polymer composite was evaluated using the piezoelectric strain constant d33. The d33 is one of the indices of the piezoelectric properties for piezoelectric materials. As a result, it was confirmed that d33 of the pseudo‐1‐3 piezoelectric ceramic/polymer composite increased with the increase of the electric filed strength applied at fabrication process, though, it reached a constant value at a certain strength value. Further it was confirmed that dielectric constant of the matrix had a small influence on d33 of the pseudo‐1‐3 piezoelectric ceramic/polymer composite, however, in case of matrix of lower Young's modulus, d33 was increase. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41817.

Piezoelectric Ceramics for Use in Multilayer Actuators and Energy Harvesters

Microstructural and piezoelectric properties of 0.72Pb(Zr1−xTix)–0.28Pb(Zn0.4Ni0.6)1/3Nb2/3O3 (PZ1−xTx‐PZNN) ceramics with 0.50 ≤ x ≤ 0.55 were investigated for evaluating the possibility of their use in multilayer actuators and energy harvesters, which demand a large piezoelectric strain constant (d33) and a small dielectric constant (εT33/εo). The PZ0.47T0.53‐PZNN ceramic with a morphotropic phase boundary (MPB) composition showed large d33 and εT33/εo values, making it unsuitable for use in multilayer actuators and energy harvesters. However, the PZ0.48T0.52‐PZNN ceramic with a rhombohedral structure showed a small εT33/εo value of 1605, yet maintained a large d33 of 550 pC/N. Thermal stimulation did not have any significant effect on the piezoelectric properties of this specimen, except for a slight increase in the εT33/εo value upon heating the specimen at 150°C for 4 h. In an effort to reduce the sintering temperature, CuO was used as an additive for the ceramic. As a result, the CuO‐added PZ0.48T0.52‐PZNN ceramic was well sintered at 900°C. In particular, the 1.0 mol% CuO‐added PZ0.48T0.52‐PZNN ceramic exhibited a large d33 value of 554 pC/N and a small εT33/εo value of 1620, making it highly suitable for use in multilayer actuators and energy harvesters.

Active control of honeycomb sandwich plate using MFC piezoelectric actuators

This paper deals with the vibration control of a cantilever honeycomb sandwich plate by using Macro-Fiber Compos- ite (MFC) piezoelectric actuator. Firstly, the honeycomb plate is equivalent to an orthogonal anisotropic plate. Secondly driving force and bending moment formulas of MFC actuator are derived based on the constitutive relations of the piezoelectric mate- rial, the equivalent parameters and bend deformation theory. The result reveals that driving force and bending moment not only depend on the driving voltage and piezoelectric strain constants (d33), but also have relationship with the elastic modulus of honeycomb plate. To simulate the vibration of cantilever honeycomb plate structure, the governing equation of the plate bonded with MFC actuators is derived. Finally, the vibration by proportional derivative (PD) control of system with MFC actuator is simulated. The results show that better control performance is obtained by using MFC actuator when system under impulse excitation and steady state sine excitation. The vibration amplitude is diminished over 75% under PD control.

Fabrication of Piezoelectric-Rubber of Large Piezoelectric Property

ABSTRACTIn the previous investigation, piezoelectric properties of the ‘Aligned-type’ in which the piezoelectric-ceramic particles are formed in linear aggregates in the rubber, remarkable piezoelectric properties were confirmed. In this investigation, to further enhance the piezoelectric properties of the Aligned-type, the influence of the matrix properties was investigated. The properties on which we focused were the dielectric constant and the Young’s modulus. Four kinds of matrix materials whose dielectric constant and Young’s modulus are different from each other; Silicone gel, Silicone rubber, Urethane rubber and Poly-methyl-methacrylate were investigated. As a result of measurement of the piezoelectric strain constant d33 of the Aligned-Type, it was confirmed that though the influence of the dielectric constant of the matrix material was small, the lower the Young’s modulus of the matrix was, the higher d33 was.

Evaluation of piezoelectric material properties for a higher power output from energy harvesters with insight into material selection using a coupled piezoelectric-circuit-finite element method

Piezoelectric material properties have substantial influence on electrical power output from piezoelectric energy harvesters (PEHs). Understanding their influences is the first step in designing effective PEHs to generate higher power outputs. This paper uses a coupled piezoelectric-circuit-finite element method to study the power outputs of different types of piezoelectric materials, including single crystal, polyvinylidene fluoride (PVDF), and soft and hard lead zirconate titanate (PZT) materials. The purpose of this study is to try to gain an understanding of which piezoelectric material property--the elastic compliance s11, the piezoelectric strain constant d31, the piezoelectric stress constant g31, and the relative dielectric constant ϵ(T)r33, and the associated material properties of the d31 × g31, called the figure of merit (FOM), and the coupling coefficient k31--dominates the power output. A rectangular piezoelectric plate under a low-frequency excitation is used to evaluate piezoelectric material properties for a higher power output. It was found that 1) d31 is a more dominant material property over other material properties for higher power output; 2) FOM was more linearly related to the power output than either the k31 or the d31; and 3) ϵ(T)r33 had some role; when the materials have an identical d31; a lower ϵ(T)r33 was preferred. Because of unexplained outliers, no single material parameter was able to be recommended as selection criteria, but combined FOM with d31 parameters is recommended for selection of piezoelectric material for a higher power output from PEHs.

High energy-density 0.72Pb(Zr0.47Ti0.53)O3-0.28Pb[(Zn0.45Ni0.55)1/3Nb2/3]O3 thick films fabricated by tape casting for energy-harvesting-device applications

0.72Pb(Zr0.47Ti0.53)O3-0.28Pb[(Zn0.45Ni0.55)1/3Nb2/3]O3 (0.72PZT-0.28PZNN) thick films were prepared by using a tape casting method to develop new materials with high energy-density applicable to energy-harvesting devices. The piezoelectric strain constant (d 33), dielectric constant (ɛ 33 /ɛ 0), piezoelectric voltage constant (g 33) and transduction coefficient (d 33·g 33) of the films were affected by the sintering temperature. These results could be attributed to the crystal structure, microstructures and secondary phases. However, the dielectric loss (tanδ) of the films was not changed remarkably with increasing sintering temperature. Typically, a d 33 of 452 pC/N, ɛ 33 /ɛ 0 of 1444, d 33·g 33 of 20,340 × 10−15 m2/N and tanδ of 0.15% were obtained for the films sintered at 1050 °C for 1 h. The power generation performance of the piezoelectric unimorph cantilever was assessed to demonstrate the feasibility of the 0.72PZT-0.28PZNN piezoelectric thick film. Also, theoretical models were employed to predict the resonance frequency of the unimorph cantilever generator, and the predicted values were compared with experimental data.

Influence of Calcined Temperature on the Piezoelectric Properties of (Na0.48K0.47Li0.05)NbO3 Lead-Free Piezoelectric Ceramics Doped with CuO

Na0.48K0.47Li0.05)NbO3(NKLN)Lead-free piezoelectric ceramics doped with CuO were prepared by traditional solid-state reaction method. Influence of calcined temperature on the material phase of NKLN lead-free piezoelectric ceramics doped with CuO by X-ray diffraction (XRD) and the influence of calcined temperature and sintered temperature on the properties of NKLN lead-free piezoelectric ceramics doped with CuO by others analysis method. The results show that the best calcined temperature is got, when calcined temperature is up to 850 °C, the mixed phase disappeares, a single phase perovskites structure is formed. With the increase of calcined temperature, piezoelectric strain constant (d33) planar electromechanical coupling factor (Kp) of NKLN lead-free piezoelectric ceramics increase first and then decrease, while only dielectric loss (tanδ) decreases first and then increases.The best calcined temperature is 850 °C, the best sintered temperature is 1080 °C, the NKLN lead-free piezoelectric ceramics doped with CuO with good comprehensive properties are obtained, whose d33 , Kp , tanδ are 85 pC/N, 0.3, 0.038, respectively.

Behaviour of Pb (Ni1/3Sb2/3)O3–PbZrTiO3 ferroelectric ceramics under cyclic electric loading

This study investigates the behavior of Pb(1−z)Laz (NiSb)0.05 [(Zr0.52 Ti0.48)1−Z/4]0.95O3 (La-PNS-PZT) ceramics where z = 0.01–0.05 in response to cyclic electrical loading. Samples were fabricated by mixed oxide route and subjected to electrical stress by applying the electric load of 1,500 V, along the polar axis, with fatigue amplitudes of 20 V. Impedance and resonance frequency response was studied after every 106 cycles. Degradation in electromechanical coupling factor (kp), piezoelectric strain constant (d33) and dielectric constant (\( K_{3}^{T} \)) were also studied and correlated with structural properties. Results revealed that the La-PNS-PZT composition containing 3 mol% of lanthanum could be more suitable for actuator applications since it shows minimum degradation in properties after 1012 cycles of electric load.

Investigation of the dielectric, elastic, and piezoelectric properties of Cs2TeMo3O12 crystals

The complete sets of dielectric, elastic, and piezoelectric constants of Cs2TeMo3O12 crystals at room temperature were determined by means of the resonant technique and impedance analysis. The piezoelectric strain constants d33 and d15 were on the order of 20.3 and 29.2 pC/N, respectively, with the electromechanical coupling coefficients being k33 = 36.6% and k15 = 14.3%. Moreover, temperature dependence of the electro-elastic coefficients was measured in the range of 0–150 °C, where the elastic constant s44 was found to possess relatively low temperature coefficient (Ts44(1) = 77 × 10−6/ °C), and the variations of d33 and k33 were less than 3.5% and 1.0%, respectively.

High piezoelectricity 0–3 cement-based piezoelectric composites

0–3 cement-based piezoelectric composites were prepared with Portland cement as matrix, lead zirconate titanate (abbreviation PZT) as functional phase and powder with high dielectric constant and high specific surface area as enhanced phase. The composites were fabricated with compacted method and the compressive strength was 96MPa. Results indicated that, with 1.5kV/mm polarization voltage and steam curing, the 24h piezoelectric strain constant d33 was 32.4pC/N when the contents of PZT and enhanced phase were 60vol.% and 20wt.%, respectively; d33 exceeded 70pC/N after curing at room temperature and dry atmosphere for 38days; gradually, it reached a constant value 99.0pC/N after 90days. This exhibited superior piezoelectric properties.

Study on Ce and La Doped 0.85NBT-0.144KBT-0.006BT Lead-Free Piezoelectric Ceramics

0.85(Na0.5Bi0.5)TiO3-0.144(K0.5Bi0.5)TiO3-0.006BaTiO3(0.85NBT-0.144KBT-0.006BT) lead-free piezoelectric ceramics was prepared by conventional ceramic technique. The influence of La2O3 doping amount and CeO2 doping amount on properties , crystal structure and surface topography of 0.85NBT-0.144KBT-0.006BT ceramics were investigated by X-ray diffraction (XRD), scanning electron microscope (SEM) and other analytic methods. It shows that all compositions show the characteristics of pure perovskite structure solid states, La2O3 and CeO2 doping only changes crystal cell dimension rather than crystal structure. The piezoelectric strain constant (d33) starts increasing and then decreasing, the dielectric constant (εT33/ε0) increases, the dielectric loss (tanδ) starts increasing and then decreasing and then increasing while La2O3 doping amount increasing. d33 and εT33/ε0of ceramics starts increasing and then decreasing, tanδ decreases while CeO2 doping amount increasing . When the La2O3 doping amount is up to 0.4 wt.%, the doped samples show good performances with d33=151 pC/N, εT33/ε0=1543 and tanδ=4.3%. When the CeO2 doping amount is 0.1 wt.%, the doped samples show good performances with d33=156 pC/N, εT33/ε0=1364 and tanδ=3.8%. La2O3 doping promotes crystal grain growth, CeO2 doping makes grain crystal size uniform, changes tetragonal into granular structure and restrains crystal grain growth.