Phase structure and piezoelectric properties of Li-modified NKLN lead-free piezoelectric ceramics

International Nuclear Information System (INIS)

Kim, Sin-Woong; Lee, Sung-Chan; Kim, Min-Soo; Jeong, Soon-Jong; Kim, In-Sung; Song, Jae-Sung

2012-01-01

Through the low-temperature sintering method, a sintered body with excellent characteristics was produced in an eco-friendly niobate-based piezoelectric ceramic, whose application was low in expectation due to poor sinterability. Li 2 CO 3 was added in excess to (Na 0.49 K 0.45 Li 0.06 )NbO 3 , and ceramics were manufactured using a commercial sintering method. Then, the sinterability and the piezoelectric properties of the specimens containing varying amounts of Li 2 CO 3 were investigated. The microstructure demonstrated the typical abnormal grain growth tendencies with the addition of Li 2 CO 3 , and this was explained through changes in the critical driving force in the interface reaction-controlled nucleation and growth theory. When the specimen had been sintered at 1000 .deg. C for 4 hours in air after the addition of 1.5 mol% Li 2 CO 3 , the sintered body showed outstanding characteristics with a piezoelectric coefficient of 180 pC/N, an electromechanical coupling coefficient of 0.32, and a dielectric constant of 975. These results showed that eco-friendly niobate-based ceramics, whose use in applications was expected to be difficult in spite of their excellent properties, could be used to produce piezoelectric materials with outstanding properties through a commercial low-temperature sintering method using additives.

Phase structure and piezoelectric properties of Li-modified NKLN lead-free piezoelectric ceramics

Energy Technology Data Exchange (ETDEWEB)

Kim, Sin-Woong; Lee, Sung-Chan; Kim, Min-Soo; Jeong, Soon-Jong; Kim, In-Sung; Song, Jae-Sung [Korea Electrotechnology Research Institute, Changwon (Korea, Republic of)

2012-09-15

Through the low-temperature sintering method, a sintered body with excellent characteristics was produced in an eco-friendly niobate-based piezoelectric ceramic, whose application was low in expectation due to poor sinterability. Li{sub 2}CO{sub 3} was added in excess to (Na{sub 0.49}K{sub 0.45}Li{sub 0.06})NbO{sub 3}, and ceramics were manufactured using a commercial sintering method. Then, the sinterability and the piezoelectric properties of the specimens containing varying amounts of Li{sub 2}CO{sub 3} were investigated. The microstructure demonstrated the typical abnormal grain growth tendencies with the addition of Li{sub 2}CO{sub 3}, and this was explained through changes in the critical driving force in the interface reaction-controlled nucleation and growth theory. When the specimen had been sintered at 1000 .deg. C for 4 hours in air after the addition of 1.5 mol% Li{sub 2}CO{sub 3}, the sintered body showed outstanding characteristics with a piezoelectric coefficient of 180 pC/N, an electromechanical coupling coefficient of 0.32, and a dielectric constant of 975. These results showed that eco-friendly niobate-based ceramics, whose use in applications was expected to be difficult in spite of their excellent properties, could be used to produce piezoelectric materials with outstanding properties through a commercial low-temperature sintering method using additives.

An equivalent dipole analysis of PZT ceramics and lead-free piezoelectric single crystals

Directory of Open Access Journals (Sweden)

Andrew J. Bell

2016-06-01

Full Text Available The recently proposed Equivalent Dipole Model for describing the electromechanical properties of ionic solids in terms of 3 ions and 2 bonds has been applied to PZT ceramics and lead-free single crystal piezoelectric materials, providing analysis in terms of an effective ionic charge and the asymmetry of the interatomic force constants. For PZT it is shown that, as a function of composition across the morphotropic phase boundary, the dominant bond compliance peaks at 52% ZrO2. The stiffer of the two bonds shows little composition dependence with no anomaly at the phase boundary. The effective charge has a maximum value at 50% ZrO2, decreasing across the phase boundary region, but becoming constant in the rhombohedral phase. The single crystals confirm that both the asymmetry in the force constants and the magnitude of effective charge are equally important in determining the values of the piezoelectric charge coefficient and the electromechanical coupling coefficient. Both are apparently temperature dependent, increasing markedly on approaching the Curie temperature.

Low sintering temperature and high piezoelectric properties of Li-doped (Ba,Ca)(Ti,Zr)O3 lead-free ceramics

International Nuclear Information System (INIS)

Chen, Xiaoming; Ruan, Xuezheng; Zhao, Kunyun; He, Xueqing; Zeng, Jiangtao; Li, Yongsheng; Zheng, Liaoying; Park, Chul Hong; Li, Guorong

2015-01-01

Highlights: • Li-doped Ba 0.85 Ca 0.15 Ti 0.9 Zr 0.1 O 3 (BCZT) lead-free piezoceramics were prepared by the two-step synthesis and solid-state reaction method. • Their sintering temperature decreases from about 1540 °C down to about 1400 °C. • With the proper addition of Li, the densities and grain sizes of ceramics increase. • The ceramics not only have the characteristics of hard piezoceramics but also possesses the features of soft piezoceramics at low sintering temperature. - Abstract: Li-doped Ba 0.85 Ca 0.15 Ti 0.9 Zr 0.1 O 3 (BCZT) lead-free piezoelectric ceramics were prepared by the two-step synthesis and the solid-state reaction method. The density and grain size of ceramics sufficiently increases by Li-doped sintering aid, and their sintering temperature decreases from about 1540 °C down to about 1400 °C. X-ray diffraction reveals that the phase structure of Li-doped BCTZ ceramics is changed with the sintering temperature, which is consistent with their phase transition observed by the temperature-dependent dielectric curves. The well-poled Li-doped BCZT ceramics show a high piezoelectric constant d 33 (512 pC/N) and a planar electromechanical coupling factor k p (0.49), which have the characteristics of soft Pb(Zr,Ti)O 3 (PZT) piezoceramic, on the other hand, the mechanical quality factor Q m is about 190, which possesses the features of hard PZT piezoceramics. The enhanced properties of the Li-doped BCZT are explained by the combination of Li-doped effect and sintering effect on the microstructure and the phase transition around room temperature

Morphotropic NaNbO{sub 3}-BaTiO{sub 3}-CaZrO{sub 3} lead-free ceramics with temperature-insensitive piezoelectric properties

Energy Technology Data Exchange (ETDEWEB)

Zuo, Ruzhong, E-mail: piezolab@hfut.edu.cn, E-mail: rzzuo@hotmail.com; Qi, He; Fu, Jian [Institute of Electro Ceramics and Devices, School of Materials Science and Engineering, Hefei University of Technology, Hefei, 230009 (China)

2016-07-11

A morphotropic NaNbO{sub 3}-based lead-free ceramic was reported to have temperature-insensitive piezoelectric and electromechanical properties (d{sub 33} = 231 pC/N, k{sub p} = 35%, T{sub c} = 148 °C, and low-hysteresis strain ∼0.15%) in a relatively wide temperature range. This was fundamentally ascribed to the finding of a composition-axis vertical morphotropic phase boundary in which coexisting ferroelectric phases are only compositionally driven and thermally insensitive. Both phase coexistence and nano-scaled domain morphology deserved well enhanced electrical properties, as evidenced by means of synchrotron x-ray diffraction and transmission electron microscopy. Our study suggests that the current lead-free ceramic would be a very promising piezoelectric material for actuator and sensor applications.

Transmission electron microscopy investigation of the microstructural mechanisms for the piezoelectricity in lead-free perovskite ceramics

Energy Technology Data Exchange (ETDEWEB)

Ma, Cheng [Iowa State Univ., Ames, IA (United States)

2012-01-01

Lead-free materials with superior piezoelectricity are in increasingly urgent demand in the current century, because the industrial standard Pb(Zr,Ti)O₃-based piezoelectrics, which contain over 60 weight% of the toxic element lead, pose severe environmental hazards. Although significant research efforts have been devoted in the past decade, no effective lead-free substitute for Pb(Zr,Ti)O₃ has been identified yet. One of the primary hindrances to the development of lead-free piezoelectrics lies in the ignorance of the microstructural mechanism for the electric-field-induced strains in the currently existing compositions. In this dissertation, the microstructural origin for the high piezoelectricity in (1-x)(Bi_1/2Na_1/2)TiO₃-xBaTiO₃ [(1-x)BNT-xBT], the most widely studied lead-free piezoelectric system, has been elucidated.

Lead-free piezoceramics.

Science.gov (United States)

Saito, Yasuyoshi; Takao, Hisaaki; Tani, Toshihiko; Nonoyama, Tatsuhiko; Takatori, Kazumasa; Homma, Takahiko; Nagaya, Toshiatsu; Nakamura, Masaya

2004-11-04

Lead has recently been expelled from many commercial applications and materials (for example, from solder, glass and pottery glaze) owing to concerns regarding its toxicity. Lead zirconium titanate (PZT) ceramics are high-performance piezoelectric materials, which are widely used in sensors, actuators and other electronic devices; they contain more than 60 weight per cent lead. Although there has been a concerted effort to develop lead-free piezoelectric ceramics, no effective alternative to PZT has yet been found. Here we report a lead-free piezoelectric ceramic with an electric-field-induced strain comparable to typical actuator-grade PZT. We achieved this through the combination of the discovery of a morphotropic phase boundary in an alkaline niobate-based perovskite solid solution, and the development of a processing route leading to highly textured polycrystals. The ceramic exhibits a piezoelectric constant d33 (the induced charge per unit force applied in the same direction) of above 300 picocoulombs per newton (pC N(-1)), and texturing the material leads to a peak d33 of 416 pC N(-1). The textured material also exhibits temperature-independent field-induced strain characteristics.

Fabrication and Characterization of Aligned Flexible Lead-Free Piezoelectric Nanofibers for Wearable Device Applications

Directory of Open Access Journals (Sweden)

Sang Hyun Ji

2018-03-01

Full Text Available Flexible lead-free piezoelectric nanofibers, based on BNT-ST (0.78Bi0.5Na0.5TiO3-0.22SrTiO3 ceramic and poly(vinylidene fluoride-trifluoroethylene (PVDF-TrFE copolymers, were fabricated by an electrospinning method and the effects of the degree of alignment in the nanofibers on the piezoelectric characteristics were investigated. The microstructure of the lead-free piezoelectric nanofibers was observed by field emission scanning electron microscope (FE-SEM and the orientation was analyzed by fast Fourier transform (FFT images. X-ray diffraction (XRD analysis confirmed that the phase was not changed by the electrospinning process and maintained a perovskite phase. Polarization-electric field (P-E loops and piezoresponse force microscopy (PFM were used to investigate the piezoelectric properties of the piezoelectric nanofibers, according to the degree of alignment—the well aligned piezoelectric nanofibers had higher piezoelectric properties. Furthermore, the output voltage of the aligned lead-free piezoelectric nanofibers was measured according to the vibration frequency and the bending motion and the aligned piezoelectric nanofibers with a collector rotation speed of 1500 rpm performed the best.

Enhanced piezoelectricity in (1 -x)Bi1.05Fe1-yAyO3-xBaTiO3 lead-free ceramics: site engineering and wide phase boundary region.

Science.gov (United States)

Zheng, Ting; Jiang, Zhenggen; Wu, Jiagang

2016-07-28

Site engineering has been employed to modulate the piezoelectric activity of high temperature (1 -x)Bi1.05Fe1-yScyO3-xBaTiO3 lead-free ceramics fabricated by a conventional solid-state method together with a quenching technique. The effects of x and y content on the phase structure, microstructure, and electrical properties have been investigated in detail. A wide rhombohedral (R) to pseudo-cubic (C) phase boundary was formed in the ceramics with x = 0.30 and 0 ≤y≤ 0.07, thus leading to enhanced piezoelectricity (d33 = 120-180 pC N(-1)), ferroelectricity (Pr = 19-22 μC cm(-2)) and a high Curie temperature (TC = 478-520 °C). In addition, the influence of different element substitutions for Fe(3+) on phase structure and electrical behavior was also investigated. Improved piezoelectricity (d33 = 160-180 pC N(-1)) and saturated P-E loops can be simultaneously achieved in the ceramics with A = Sc, Ga, and Al due to the R-C phase boundary. As a result, site engineering may be an efficient way to modulate the piezoelectricity of BiFeO3-BaTiO3 lead-free ceramics.

Disk-type piezoelectric transformer of a Na0.5K0.5NbO3–CuNb2O6 lead-free ceramic for driving T5 fluorescent lamp

International Nuclear Information System (INIS)

Yang, Ming-Ru; Chu, Sheng-Yuan; Chan, I.-Hao; Yang, Song-Ling

2012-01-01

Highlights: ► CuNb 2 O 6 dopants were doped into NKN ceramics not only improved the density but also exhibited superior piezoelectric characteristic, temperature stability of resonance frequency. ► Lead-free NKN-01CN piezoelectric transformer was simplified as an equivalent circuit and analyzed using MATLAB. ► An 8W T5 fluorescent lamp was successfully driven by the NKN-01CN piezoelectric transformer. - Abstract: Lead-free (Na 0.5 K 0.5 )NbO 3 (NKN) ceramics doped with 1 mol% CuNb 2 O 6 (CN) ceramics were prepared using the conventional mixed oxide method, with a sintering temperature of 1075 °C. Microstructural analyses of the NKN–01CN ceramics were carried out and compared, using X-ray diffraction (XRD). NKN–01CN ceramics sintered at 1075 °C not only exhibited excellent ‘hard’ piezoelectric properties of k p = 40%, k t = 45%, k 33 = 57%, a ferroelectric property of E c = 23 kV/cm, and an extraordinarily high mechanical quality factor (Q m ) of 1933 but also showed excellent stability with temperature (TCF = −154 ppm/°C). The piezoelectric transformer was simplified, using an equivalent circuit, and analyzed, using MATLAB; the simulation data agreed well with the experimental results. An efficiency of 95.7% was achieved for the NKN–01CN piezoelectric transformer with load resistance of 20 kΩ. An 8 W T5 fluorescent lamp was successfully driven by the NKN–01CN piezoelectric transformer.

Low sintering temperature and high piezoelectric properties of Li-doped (Ba,Ca)(Ti,Zr)O{sub 3} lead-free ceramics

Energy Technology Data Exchange (ETDEWEB)

Chen, Xiaoming [Key Laboratory of Inorganic Functional Materials and Devices, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China); University of Chinese Academy of Sciences, Beijing 100039 (China); School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237 (China); Ruan, Xuezheng; Zhao, Kunyun [Key Laboratory of Inorganic Functional Materials and Devices, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China); He, Xueqing [School of Materials and Metallurgy, Northeastern University, Shenyang 110004 (China); Zeng, Jiangtao, E-mail: zjt@mail.sic.ac.cn [Key Laboratory of Inorganic Functional Materials and Devices, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China); Li, Yongsheng [School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237 (China); Zheng, Liaoying [Key Laboratory of Inorganic Functional Materials and Devices, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China); Park, Chul Hong [Department of Physics Education, Pusan National University, Pusan 609735 (Korea, Republic of); Li, Guorong [Key Laboratory of Inorganic Functional Materials and Devices, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China)

2015-05-25

Highlights: • Li-doped Ba{sub 0.85}Ca{sub 0.15}Ti{sub 0.9}Zr{sub 0.1}O{sub 3} (BCZT) lead-free piezoceramics were prepared by the two-step synthesis and solid-state reaction method. • Their sintering temperature decreases from about 1540 °C down to about 1400 °C. • With the proper addition of Li, the densities and grain sizes of ceramics increase. • The ceramics not only have the characteristics of hard piezoceramics but also possesses the features of soft piezoceramics at low sintering temperature. - Abstract: Li-doped Ba{sub 0.85}Ca{sub 0.15}Ti{sub 0.9}Zr{sub 0.1}O{sub 3} (BCZT) lead-free piezoelectric ceramics were prepared by the two-step synthesis and the solid-state reaction method. The density and grain size of ceramics sufficiently increases by Li-doped sintering aid, and their sintering temperature decreases from about 1540 °C down to about 1400 °C. X-ray diffraction reveals that the phase structure of Li-doped BCTZ ceramics is changed with the sintering temperature, which is consistent with their phase transition observed by the temperature-dependent dielectric curves. The well-poled Li-doped BCZT ceramics show a high piezoelectric constant d{sub 33} (512 pC/N) and a planar electromechanical coupling factor k{sub p} (0.49), which have the characteristics of soft Pb(Zr,Ti)O{sub 3} (PZT) piezoceramic, on the other hand, the mechanical quality factor Q{sub m} is about 190, which possesses the features of hard PZT piezoceramics. The enhanced properties of the Li-doped BCZT are explained by the combination of Li-doped effect and sintering effect on the microstructure and the phase transition around room temperature.

Lead-free piezoelectric (K,Na)NbO3-based ceramic with planar-mode coupling coefficient comparable to that of conventional lead zirconate titanate

Science.gov (United States)

Ohbayashi, Kazushige; Matsuoka, Takayuki; Kitamura, Kazuaki; Yamada, Hideto; Hishida, Tomoko; Yamazaki, Masato

2017-06-01

We developed a (K,Na)NbO3-based lead-free piezoelectric ceramic with a KTiNbO5 system, (K1- x Na x )0.86Ca0.04Li0.02Nb0.85O3-δ-K0.85Ti0.85Nb1.15O5-BaZrO3-Fe2O3-MgO (K1- x N x N-NTK-FM). K1- x N x N-NTK-FM ceramic exhibits a very dense microstructure and a coupling coefficient of k p = 0.59, which is almost comparable to that of conventional lead zirconate titanate (PZT). The (K,Na)NbO3-based ceramic has the Γ15 mode for a wide x range. The nanodomains of orthorhombic (K,Na)NbO3 with the M3 mode coexist within the tetragonal Γ15 mode (K,Na)NbO3 matrix. Successive phase transition cannot occur with increasing x. The maximum k p is observed at approximately the minimum x required to generate the M3 mode phase. Unlike the behavior at the morphotropic phase boundary (MPB) in PZT, the characteristics of K1- x N x N-NTK-FM ceramic in this region changed moderately. This gentle phase transition seems to be a relaxor, although the diffuseness degree is not in line with this hypothesis. Furthermore, piezoelectric properties change from “soft” to “hard” upon the M3 mode phase aggregation.

Fabrication of high-power piezoelectric transformers using lead-free ceramics for application in electronic ballasts.

Science.gov (United States)

Yang, Song-Ling; Chen, Shih-Ming; Tsai, Cheng-Che; Hong, Cheng-Shong; Chu, Sheng-Yuan

2013-02-01

CuO is doped into (Na(0.5)K(0.5))NbO(3) (NKN) ceramics to improve the piezoelectric properties and thus obtain a piezoelectric transformer (PT) with high output power. In X-ray diffraction patterns, the diffraction angles of the CuO-doped NKN ceramics shift to lower values because of an expansion of the lattice volume, thus inducing oxygen vacancies and enhancing the mechanical quality factor. A homogeneous microstructure is obtained when NKN is subjected to CuO doping, leading to improved electrical properties. PTs with different electrode areas are fabricated using the CuO-doped NKN ceramics. Considering the efficiency, voltage gain, and temperature rise of PTs at a load resistance of 1 kΩ, PTs with an electrode with an inner diameter of 15 mm are combined with the circuit design for driving a 13-W T5 fluorescent lamp. A temperature rise of 6°C and a total efficiency of 82.4% (PT and circuit) are obtained using the present PTs.

Polymorphic phase transition dependence of piezoelectric properties in (K0.5Na0.5)NbO3-(Bi0.5K0.5)TiO3 lead-free ceramics

International Nuclear Information System (INIS)

Du Hongliang; Zhou Wancheng; Luo Fa; Zhu Dongmei; Qu Shaobo; Li Ye; Pei Zhibin

2008-01-01

Lead-free ceramics (1 - x)(K 0.5 Na 0.5 )NbO 3 -x(Bi 0.5 K 0.5 )TiO 3 [(1 - x)KNN-xBKT] were synthesized by conventional solid-state sintering. The phase structure, microstructure and electrical properties of (1 - x)KNN-xBKT ceramics were investigated. At room temperature, the polymorphic phase transition (from the orthorhombic to the tetragonal phase) (PPT) was identified at x = 0.02 by the analysis of x-ray diffraction patterns and dielectric spectroscopy. Enhanced electrical properties (d 33 = 251 pC N -1 , k p = 0.49, k t = 0.50, ε 33 T / ε 0 =1260, tan δ = 0.03 and T C = 376 deg. C) were obtained in the ceramics with x = 0.02 owing to the formation of the PPT at 70 deg. C and the selection of an optimum poling temperature. The related mechanisms for high piezoelectric properties in (1 - x)KNN-xBKT (x = 0.02) ceramics were discussed. In addition, the results confirmed that the selection of the optimum poling temperature was an effective way to further improve the piezoelectric properties of KNN-based ceramics. The enhanced properties were comparable to those of hard Pb(Zr, Ti)O 3 ceramics and indicated that the (1 - x)KNN-xBKT (x = 0.02) ceramic was a promising lead-free piezoelectric candidate material for actuator and transducer applications

Preparation and electrical properties of Bi0.5Na0.5TiO3-BaTiO3-KNbO3 lead-free piezoelectric ceramics

International Nuclear Information System (INIS)

Ni Haimin; Luo Laihui; Li Weiping; Zhu Yuejin; Luo Haosu

2011-01-01

Research highlights: → Bi 0.47 Na 0.47 Ba 0.06 TiO 3 -KNbO 3 ceramics exhibit excellent piezoelectric properties. → The optimized properties of the ceramics: d 33 = 195 pC/N; k t = 58.9; Q m = 113; E c = 19.5 kV/cm. → KNbO 3 has diffused into the Bi 0.47 Na 0.47 Ba 0.06 TiO 3 lattices to form a new solid solution. → Macro-micro domain switching occurs at depolarization temperature T d . - Abstract: Lead-free (1 - x)Bi 0.47 Na 0.47 Ba 0.06 TiO 3 -xKNbO 3 (BNBT-xKN, x = 0-0.08) ceramics were prepared by ordinary ceramic sintering technique. The piezoelectric, dielectric and ferroelectric properties of the ceramics are investigated and discussed. The results of X-ray diffraction (XRD) indicate that KNbO 3 (KN) has diffused into Bi 0.47 Na 0.47 Ba 0.06 TiO 3 (BNBT) lattices to form a solid solution with a pure perovskite structure. Moderate additive of KN (x ≤ 0.02) in BNBT-xKN ceramics enhance their piezoelectric and ferroelectric properties. Three dielectric anomaly peaks are observed in BNBT-0.00KN, BNBT-0.01KN and BNBT-0.02KN ceramics. With the increment of KN in BNBT-xKN ceramics, the dielectric anomaly peaks shift to lower temperature. BNBT-0.01KN ceramic exhibits excellent piezoelectric properties and strong ferroelectricity: piezoelectric coefficient, d 33 = 195 pC/N; electromechanical coupling factor, k t = 58.9 and k p = 29.3%; mechanical quality factor, Q m = 113; remnant polarization, P r = 41.8 μC/cm 2 ; coercive field, E c = 19.5 kV/cm.

Effects of improved process for CuO-doped NKN lead-free ceramics on high-power piezoelectric transformers.

Science.gov (United States)

Yang, Song-Ling; Tsai, Cheng-Che; Liou, Yi-Cheng; Hong, Cheng-Shong; Li, Bing-Jing; Chu, Sheng-Yuan

2011-12-01

In this paper, the effects of the electrical proper- ties of CuO-doped (Na(0.5)K(0.5))NbO(3) (NKN) ceramics prepared separately using the B-site oxide precursor method (BO method) and conventional mixed-oxide method (MO method) on high-power piezoelectric transformers (PTs) were investigated. The performances of PTs made with these two substrates were compared. Experimental results showed that the output power and temperature stability of PTs could be enhanced because of the lower resonant impedance of the ceramics prepared using the BO method. In addition, the output power of PTs was more affected by the resonant impedance than by the mechanical quality factor (Q(m)) of the ceramics. The PTs fabricated with ceramics prepared using the BO method showed a high efficiency of more than 94% and a maximum output power of 8.98 W (power density: 18.3 W/cm(3)) with temperature increase of 3°C under the optimum load resistance (5 kΩ) and an input voltage of 150 V(pp). This output power of the lead-free disk-type PTs is the best reported so far.

Lead-free piezoelectric materials and ultrasonic transducers for medical imaging

Directory of Open Access Journals (Sweden)

Elaheh Taghaddos

2015-06-01

Full Text Available Piezoelectric materials have been vastly used in ultrasonic transducers for medical imaging. In this paper, firstly, the most promising lead-free compositions with perovskite structure for medical imaging applications have been reviewed. The electromechanical properties of various lead-free ceramics, composites, and single crystals based on barium titanate, bismuth sodium titanate, potassium sodium niobate, and lithium niobate are presented. Then, fundamental principles and design considerations of ultrasonic transducers are briefly described. Finally, recent developments in lead-free ultrasonic probes are discussed and their acoustic performance is compared to lead-based transducers. Focused transducers with different beam focusing methods such as lens focusing and mechanical shaping are explained. Additionally, acoustic characteristics of lead-free probes including the pulse-echo results as well as their imaging capabilities for various applications such as phantom imaging, in vitro intravascular ultrasound imaging of swine aorta, and in vivo or ex vivo imaging of human eyes and skin are reviewed.

Fabrication of lead-free piezoelectric Li2CO3-added (Ba,Ca)(Ti,Sn)O3 ceramics under controlled low oxygen partial pressure and their properties

Science.gov (United States)

Noritake, Kouta; Sakamoto, Wataru; Yuitoo, Isamu; Takeuchi, Teruaki; Hayashi, Koichiro; Yogo, Toshinobu

2018-02-01

Reduction-resistant lead-free (Ba,Ca)(Ti,Sn)O3 piezoceramics with high piezoelectric constants were fabricated by optimizing the amount of Li2CO3 added. Oxygen partial pressure was controlled during the sintering of (Ba,Ca)(Ti,Sn)O3 ceramics in a reducing atmosphere using H2-CO2 gas. Enhanced grain growth and a high-polarization state after poling treatment were achieved by adding Li2CO3. Optimizing the amount of Li2CO3 added to (Ba0.95Ca0.05)(Ti0.95Sn0.05)O3 ceramics sintered under a low oxygen partial pressure resulted in improved piezoelectric properties while maintaining the high sintered density. The prepared Li2CO3-added ceramic samples had homogeneous microstructures with a uniform dispersion of each major constituent element. However, the residual Li content in the 3 mol % Li2CO3-added (Ba0.95Ca0.05)(Ti0.95Sn0.05)O3 ceramics after sintering was less than 0.3 mol %. Sintered bodies of this ceramic prepared in a CO2 (1.5%)-H2 (0.3%)/Ar reducing atmosphere (PO2 = 10-8 atm at 1350 °C), exhibited sufficient electrical resistivity and a piezoelectric constant (d 33) exceeding 500 pC/N. The piezoelectric properties of this nonreducible ceramic were comparable or superior to those of the same ceramic sintered in air.

Phase transition characteristics and associated piezoelectricity of potassium-sodium niobate lead-free ceramics.

Science.gov (United States)

Wang, Yuanyu; Hu, Liang; Zhang, Qilong; Yang, Hui

2015-08-14

To achieve high piezoelectric activity and a wide sintering temperature range, the ceramic system concerning (1 - x)(K(0.48)Na(0.52))(Nb(0.96)Sb(0.04))O(3)-x[Bi(0.5)(Na(0.7)Ag(0.3))(0.5)](0.90) Zn(0.10)ZrO(3) was designed, and the rhombohedral-tetragonal (R-T) phase boundary can drive a high d(33). Phase transition characteristics as well as their effects on the electrical properties were investigated systematically. The R-T coexistence phase boundary (0.04 ≤ x ≤ 0.05) can be driven via modification with BNAZZ, and has been confirmed by XRD and temperature-dependent dielectric constants as well as Raman analysis, and the ceramics possess enhanced piezoelectric properties (d(33) ∼ 425 pC N(-1) and k(p) ∼ 0.43) and a high unipolar strain (∼0.3%). In addition, a wide sintering temperature range of 1050-1080 °C can warrant a large d(33) of 400-430 pC N(-1), which can benefit practical applications. As a result, the addition of BNAZZ is an effective method to improve the electrical properties (piezoelectricity and strain) and sintering behavior of potassium-sodium niobate ceramics.

Low temperature synthesis & characterization of lead-free BCZT ceramics using molten salt method

Science.gov (United States)

Jai Shree, K.; Chandrakala, E.; Das, Dibakar

2018-04-01

Piezoelectric properties are greatly influenced by the synthesis route, microstructure, stoichiometry of the chemical composition, purity of the starting materials. In this study, molten salt method was used to prepare lead-free BCZT ceramics. Molten salt method is one of the simplestmethods to prepare chemically-purified, single phase powders in high yield often at lower temperatures and shorten reaction time. Calcination of the molten salt synthesized powders resulted in asingle-phase perovskite structure at 1000 °C which is ˜ 350 °C less than the conventional solid-sate reaction method. With increasing calcination temperature the average template size was increased (˜ 0.5-2 µm). Formation of well dispersive templates improves the sinterability at lower temperatures. Lead-free BCZT ceramics sintered at 1500 °C for 2 h resulted in homogenous and highly dense microstructure with ˜92% of the theoretical density and a grain size of ˜ 35 µm. This highly dense microstructure could enhance the piezoelectric properties of the system.

Dual-enhancement of ferro-/piezoelectric and photoluminescent performance in Pr{sup 3+} doped (K{sub 0.5}Na{sub 0.5})NbO{sub 3} lead-free ceramics

Energy Technology Data Exchange (ETDEWEB)

Wei, Yongbin; Jia, Yanmin, E-mail: wuzheng@zjnu.cn, E-mail: ymjia@zjnu.edu.cn; Wu, Jiang; Shen, Yichao [Department of Physics, Zhejiang Normal University, Jinhua 321004 (China); Wu, Zheng, E-mail: wuzheng@zjnu.cn, E-mail: ymjia@zjnu.edu.cn [College of Geography and Environmental Sciences, Zhejiang Normal University, Jinhua 321004 (China); Luo, Haosu [Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 201800 (China)

2014-07-28

A mutual enhancement action between the ferro-/piezoelectric polarization and the photoluminescent performance of rare earth Pr{sup 3+} doped (K{sub 0.5}Na{sub 0.5})NbO{sub 3} (KNN) lead-free ceramics is reported. After Pr{sup 3+} doping, the KNN ceramics exhibit the maximum enhancement of ∼1.2 times in the ferroelectric remanent polarization strength and ∼1.25 times in the piezoelectric coefficient d{sub 33}, respectively. Furthermore, after undergoing a ferro-/piezoelectric polarization treatment, the maximum enhancement of ∼1.3 times in photoluminescence (PL) was observed in the poled 0.3% Pr{sup 3+} doped sample. After the trivalent Pr{sup 3+} unequivalently substituting the univalent (K{sub 0.5}Na{sub 0.5}){sup +}, A-sites ionic vacancies will occur to maintain charge neutrality, which may reduce the inner stress and ease the domain wall motions, yielding to the enhancement in ferro-/piezoelectric performance. The polarization-induced enhancement in PL is attributed to the decrease of crystal symmetry abound the Pr{sup 3+} ions after polarization. The dual-enhancement of the ferro-/piezoelectric and photoluminescent performance makes the Pr{sup 3+} doped KNN ceramic hopeful for piezoelectric/luminescent multifunctional devices.

Evolution of transverse piezoelectric response of lead zirconate titanate ceramics under hydrostatic pressure

International Nuclear Information System (INIS)

Li Fei; Xu Zhuo; Wei Xiaoyong; Gao Junjie; Zhang, Chonghui; Yao Xi; Jin Li

2009-01-01

The piezoelectric properties of 31-mode resonators of lead zirconate titanate ceramics under hydrostatic pressure from 0.1 to 325 MPa were evaluated by a fitting method, in which mechanical loss was taken into account. Our results based on the fitting method showed a hydrostatic pressure independent tendency of the piezoelectric coefficient and the electromechanical coupling factor because the adopted PZT ceramic can be considered as a linear system in our experiment, while two misleading tendencies of piezoelectric coefficient were obtained based on the resonance method when ignoring the contribution of the mechanical loss. (fast track communication)

Finite Element Study on Acoustic Energy Harvesting Using Lead-Free Piezoelectric Ceramics

Science.gov (United States)

Kumar, Anuruddh; Sharma, Anshul; Kumar, Rajeev; Vaish, Rahul

2018-02-01

In this article, a numerical investigation is performed for ambient acoustic energy harvesting at a low-frequency acoustic signal. A model of a quarter-wavelength resonator with a rectangular cross section is constructed, and piezoelectric-laminated bimorph plates are placed inside the system. Finite element modeling is implemented to numerically formulate the piezoelectric energy harvester. With the application of acoustic pressure at the open end of the resonator, amplified acoustic pressure inside the tube vibrates the piezolaminated bimorphs inside the tube, thus generating electric potential on the piezoelectric layers. To generate higher voltage and power in the acoustic harvester, multiple piezolaminated plates are positioned inside the resonator. The lead-free piezoelectric material K0.475Na0.475Li0.05 (Nb0.92Ta0.05Sb0.03)O3 (KNLNTS) is laminated on the host structure as a layer of piezoelectric material for the acoustic energy harvester. With the application of an acoustic sound pressure of 1 dB at the opening of the tube, a maximum output voltage of 16.3 V is measured at the first natural frequency, while the maximum power calculated is 0.033 mW. Maximum voltage is obtained when five piezoelectric bimorphs are place inside the resonator. At the second natural frequency, the maximum voltage measured is 8.40 V, obtained when eight piezoelectric bimorphs are placed inside the resonator, and the maximum power calculated is 0.020 mW.

Preparation and electrical properties of MoO{sub 3}-modified SrBi{sub 2}Nb{sub 2}O{sub 9}-based lead-free piezoelectric ceramics

Energy Technology Data Exchange (ETDEWEB)

Yao, Zhongran, E-mail: ruiqingchu@sohu.com [College of Materials Science and Engineering, Liaocheng University, Liaocheng 252059 (China); Chu, Ruiqing, E-mail: rqchu@lcu.edu.cn [College of Materials Science and Engineering, Liaocheng University, Liaocheng 252059 (China); Xu, Zhijun; Hao, Jigong; Wei, Denghu; Cheng, Renfei [College of Materials Science and Engineering, Liaocheng University, Liaocheng 252059 (China); Li, Guorong [The State Key Lab of High Performance Ceramics and Superfinemicrostructure, Shanghai Institute of Ceramics, Chinese Academy of Science, Shanghai 200050 (China)

2016-05-05

Lead-free piezoelectric ceramics, SrBi{sub 2}(Nb{sub 1-x}Mo{sub x}){sub 2}O{sub 9} (SBNM-x), were prepared by a conventional solid-state reaction method. The crystal structure, microstructure and electrical properties were systematically investigated. The X-ray diffraction analysis suggested that the substitution formed layered perovskite structure. Plate-like morphology of the grains which is characteristic for layer-structure Aurivillius compounds was clearly observed for all the samples. The excellent electrical properties (e.g., d{sub 33}∼18 pC/N, 2P{sub r}∼20.34 μC/cm{sup 2}) and a high Curie temperature (e.g., T{sub c}∼458 °C) are simultaneously obtained in the ceramics with x = 0.12. Additionally, thermal annealing studies indicated that piezoelectric constant (d{sub 33}) of SBNM-0.12 ceramic remains almost unchanged (16 pC/N, only decrease by 12%) at temperatures below 400 °C, demonstrating that the Mo-modified SBN-based ceramics are the promising candidates for high-temperature applications. - Highlights: • Higher valent cation Mo{sup 6+} substituted for B-site Nb{sup 5+} in the perovskite layers ions. • The piezoelectric constant (d{sub 33}) of SrBi{sub 2}Nb{sub 2}O{sub 9} ceramic is increased to be 18 pC/N. • The remnant polarization (2P{sub r}) of SrBi{sub 2}Nb{sub 2}O{sub 9} ceramic is increased to be 20.34 μC cm{sup −2}. • SBNM-x ceramics show good temperature stability for high temperature applications.

An ultrasonic therapeutic transducers using lead-free Na0.5K0.5NbO3-CuNb2O6 ceramics

International Nuclear Information System (INIS)

Yang, Ming-Ru; Chu, Sheng-Yuan; Tsai, Cheng-Che

2010-01-01

Research highlights: → In this paper, CN was added to NKN ceramics to decrease the sintering temperature and to improve the density and piezoelectric characteristics. The influence of CuNb 2 O 6 (CN) content on the microstructure, electrical properties, temperature stability, and mechanical properties of the synthesized samples was investigated. Results show that the samples synthesized with CN-doped not only improved the density but also exhibited superior piezoelectric characteristic, temperature stability of resonance frequency (TCF), and elastic stiffness coefficient than those of pure NKN piezoelectric ceramics. → The bulk density (4.47 g/cm 3 ), k p (40%), k t (45%), Q m (1642), C 33 D (19.64 x 10 10 N/m 2 ), TCF (-0.011%/ o C) and TCC (0.135%/ o C) values for NKN-01CN ceramics obtained from experiments show excellent 'hard' piezoelectric properties. Furthermore, a lead-free NKN-01CN ultrasonic therapeutic transducer was successfully driven by a self-tuning circuit. - Abstract: In this work, we reports on the CuNb 2 O 6 (CN) modified lead-free Na 0.5 K 0.5 NbO 3 (NKN) based piezoelectric ceramics were synthesized by solid-state reaction methods and sintered at 1075 o C for 3 h. A secondary phase of K 4 CuNb 8 O 23 was found in the XRD pattern of NKN-based ceramics as the CN dopants is 1 mol%. Microstructural analyses of un-doped and CN-doped ceramics were performed in a scanning electron microscope. The influence of CN content on the microstructure, electrical properties, temperature stability, and mechanical properties of the synthesized ceramics was investigated. The results show that the synthesized ceramics with CN-doped not only had improved density but also exhibited superior piezoelectric characteristics, temperature stability of resonance frequency (TCF), and a better elastic stiffness coefficient than those of pure NKN piezoelectric ceramics. The bulk density (4.47 g/cm 3 ), k p (40%), k t (45%), Q m (1642), C 33 D (19.64 x 10 10 N/m 2 ), TCF (-0

Preparation and characterization of Mn-doped Li{sub 0.06}(Na{sub 0.5}K{sub 0.5}){sub 0.94}NbO{sub 3} lead-free piezoelectric ceramics with surface sol-gel coatings

Energy Technology Data Exchange (ETDEWEB)

Yoo, Ae Ri; Lee, Seong Eui; Lee, Hee Chul [Korea Polytechnic University, Shiheung (Korea, Republic of)

2014-08-15

This study investigated the effects of Mn doping and sol-gel surface coating on the structural and the electrical properties of lead-free Li{sub 0.06}(K{sub 0.5}Na{sub 0.5}){sub 0.94}NbO{sub 3}(LNKN) ceramics in disc form for use as eco-friendly piezoelectric devices. The 1-mol% Mn-doped LNKN ceramic showed a relatively high piezoelectric constant owing to its high density in the case of its being annealed at a temperature of 1010 .deg. C. A Mn-doped LNKN sol-gel solution with the same composition as that of the ceramics was spin-coated and sintered on both sides of the ceramic surfaces to acquire improved electrical properties. The sol-gel surface coating could play a decisive role in filling the pores, resulting in flat and stable interfaces between the electrodes and the piezoelectric elements. As a result, the highest piezoelectric constant, d{sub 33}, of 173 pC/N could be obtained for the Mn-doped LNKN ceramics with 420-nm-thick sol-gel surface coatings.

Phase structure, dielectric, and piezoelectric properties of (K{sub 0.94-x}Na{sub x}Li{sub 0.06})(Nb{sub 0.94}Sb{sub 0.06})O{sub 3} lead-free ceramics

Energy Technology Data Exchange (ETDEWEB)

Fu, Lingling; Lin, Dunmin; Zheng, Qiaoji; Wu, Xiaochun; Xu, Chenggang [College of Chemistry and Materials Science, and Visual Computing and Virtual Reality Key Laboratory of Sichuan Province, Sichuan Normal University, Chengdu 610066 (China)

2012-11-15

Lead-free piezoelectric ceramics (K{sub 0.94-x}Na{sub x}Li{sub 0.06})(Nb{sub 0.94}Sb{sub 0.06})O{sub 3} have been fabricated by a conventional ceramic technique and the effects of K{sup +}/Na{sup +} ratio on the structure and piezoelectric properties of the ceramics have been studied. All the ceramics possess a pure perovskite structure. The coexistence of tetragonal and orthorhombic phases is formed at room temperature in the ceramics with 0.45 {<=} x {<=} 0.55. The tetragonal-orthorhombic phase-transition temperature T{sub O-T} decreases from 110 to 54 C with x increasing from 0.35 to 0.55 and then increases from 84 to 144 C with x further increasing from 0.6 to 0.7, while the Curie temperature T{sub C} deceases from 388 to 348 C with x increasing from 0.35 to 0.70. Because of the coexistence of the two phases near room temperature, the ceramics with x = 0.50 exhibit the optimum piezoelectric properties: d{sub 33} = 230 pC/N and k{sub p} = 49%. The ceramics possess good time stability of piezoelectric properties. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Mechanical bending strength of (Bi0.5Na0.5 TiO3-based lead-Free piezoelectric ceramics

Directory of Open Access Journals (Sweden)

Hiroaki Takahashi

2017-09-01

Full Text Available (Bi0.5Na0.5TiO3 [BNT] is expected as one of candidate lead-free materials because these ceramics show relatively good high-power piezoelectric properties. In this study, we tried to understand the bending strength and fracture behavior of the BNT-based ceramics. To measure the bending strength, a three-point bending test on the basis of JIS was conducted using 12.0 × 4.0 × 1.0 mm3 specimens. An average bending strength, σA, of pure BNT ceramics sintered at 1100 °C for 2, 12 and 24 h were 217, 195 and 187 MPa, respectively. It is cleared that the σA increased with decreasing the sintering time, (grain size and pore size. We also investigated the bending strength of Nb2O5 doped BNT ceramics [BNT-Nb x, x = 0.05 ∼ 1.5 wt%] and MnCO3 doped BNT ceramics [BNT-Mn x, x = 0.5 and 1.0 wt%]. Values of the σA of BNT-Nb 0.5 and BNT-Mn 0.5 were 222, and 188 MPa, respectively. It is clarified that soft dopants (Nb can improve the bending strength of BNT-based ceramics. Additionally, hot-pressed BNT [HP-BNT] were sintered at 1050 °C for 5 h, and the σA of HP-BNT was 245 MPa.

Effect of porosity on the ferroelectric and piezoelectric properties of (Ba0.85Ca0.15)(Zr0.1Ti0.9)O3 piezoelectric ceramics

DEFF Research Database (Denmark)

Yap, Emily W.; Glaum, Julia; Oddershede, Jette

2018-01-01

The ferroelectric and piezoelectric properties of (Ba0.85Ca0.15)(Zr0.1Ti0.9)O3 (BCZT) ceramics were measured as a function of porosity. Porous BCZT ceramics were fabricated using the sacrificial fugitive technique. Two different pore morphologies were induced by adding polymeric microspheres...... and fibres as the pore-forming agents. Increasing porosity led to decreasing ferroelectric and piezoelectric properties due to a reduction of polarisable BCZT ceramic available. With the benefit of being a lead-free piezoelectric material, porous BCZT ceramics may be considered for acoustic impedance...

Dielectric and piezoelectric properties of BiFeO3 modified Bi0.5Na0.5TiO3-Bi0.5K0.5TiO3 lead-free piezoelectric ceramics

International Nuclear Information System (INIS)

Zhou Changrong; Liu Xinyu; Li Weizhou

2008-01-01

The (0.82 - x)Bi 0.5 Na 0.5 TiO 3 -0.18Bi 0.5 K 0.5 TiO 3 -xBiFeO 3 (x = 0-0.07) lead-free piezoelectric ceramics were fabricated by a conventional solid-state reaction method and the effect of BiFeO 3 addition on microstructure and electrical properties of the ceramics was investigated. The specimens with x ≤ 0.05 maintained a rhombohedral-tetragonal phase coexistence and changed into a rhombohedral phase when x > 0.05 in crystal structure. The addition of BiFeO 3 caused a promoted grain growth. All the specimens reveal a low-frequency dielectric dispersion in the frequency range of 40-1 MHz. The piezoelectric constant d 33 and the electromechanical coupling factor k p show an obvious improvement by the addition of small amount of BiFeO 3 , which shows optimum values of d 33 = 170 pC/N and k p = 0.366 at x = 0.03. Contrary to the enhancement of piezoelectric properties, Q m decreases with increasing BiFeO 3 content. The mechanisms of intrinsic and extrinsic contributions to the dielectric and piezoelectric responses have been proposed. Intrinsic contributions are from the relative ion/cation shift that preserves the ferroelectric crystal structure. The remaining extrinsic contributions are from the domain-wall motion and point defects

Piezoelectric Ceramics Characterization

National Research Council Canada - National Science Library

Jordan, T

2001-01-01

... the behavior of a piezoelectric material. We have attempted to cover the most common measurement methods as well as introduce parameters of interest. Excellent sources for more in-depth coverage of specific topics can be found in the bibliography. In most cases, we refer to lead zirconate titanate (PZT) to illustrate some of the concepts since it is the most widely used and studied piezoelectric ceramic to date.

Gd2O3 doped 0.82Bi0.5Na0.5TiO3–0.18Bi0.5K0.5TiO3 lead-free piezoelectric ceramics

International Nuclear Information System (INIS)

Fu, Peng; Xu, Zhijun; Chu, Ruiqing; Li, Wei; Wang, Wei; Liu, Yong

2012-01-01

Highlights: ► Gd 2 O 3 doped BNKT18 piezoelectric ceramics were designed and prepared. ► The electrical properties of the BNKT18 ceramics are improved with the addition of Gd 2 O 3 . ► The BNKT18 ceramics doped with 0.4 wt.% Gd 2 O 3 has better electrical properties. -- Abstract: Gd 2 O 3 (0–0.8 wt.%)-doped 0.82Bi 0.5 Na 0.5 TiO 3 –0.18Bi 0.5 K 0.5 TiO 3 (BNKT18) lead-free piezoelectric ceramics were synthesized by a conventional solid-state process. The effects of Gd 2 O 3 on the microstructure, the dielectric, ferroelectric and piezoelectric properties were investigated. X-ray diffraction (XRD) data shows that Gd 2 O 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 2 O 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 2 O 3 , and the BNKT18 ceramics doped with 0.4 wt.% Gd 2 O 3 have the highest piezoelectric constant (d 33 = 137 pC/N), highest relative dielectric constant (ε r = 1023) and lower dissipation factor (tan δ = 0.044) at a frequency of 10 kHz. The BNKT18 ceramics doped with 0.2 wt.% Gd 2 O 3 have the highest planar coupling factor (k p = 0.2463).

Electrically Induced Strain and Polarization Fatigue in Lead-Free Ceramics

Science.gov (United States)

Sommer, Daniel

Piezoelectric ceramics have traditionally been used in commercial applications such as actuators and sensors. By far the most popular piezoceramics currently in use are Pb(Zr,Ti)O3-based (PZT) ceramics. PZT ceramics are able to produce large strain and polarization with the application of an electric field, and this is due to the Morphotropic phase boundary (MPB). A MPB is associated with the boundary between tetragonal and rhombohedral perovskite phases. A disadvantage of PZT ceramics is that they contain ? 60 wt. % of lead. Since lead is toxic, this poses an environmental and health hazard because lead is released into the surroundings during fabrication and disposal. Because of this, there is a push to discover lead-free alternatives that have comparable properties to PZT but none of the health risks. One possibility is Bi 1/2(Na0.8K0.2)1/2Ti0.985 Ta0.015O3 (BNKT-1.5Ta). In addition to comparable electrical properties, any lead-free alternatives must have decent fatigue resistance to be useful for applications. This thesis focuses on the fatigue properties of BNKT-1.5Ta. The composition demonstrates high strain for a given applied electric field. To determine the fatigue resistance of BNKT-1.5Ta, data was gathered on how strain and polarization changed over number of cycles. Furthermore, fatigue tests at different temperatures were performed to ascertain if temperature affected fatigue life. X-ray diffraction (XRD) patterns and dielectric measurements were also collected to further examine any change in crystal structure and relative permittivity, respectively, before and after cycling.

Advances in Lead-Free Piezoelectric Materials for Sensors and Actuators

Directory of Open Access Journals (Sweden)

Jacob L. Jones

2010-03-01

Full Text Available Piezoelectrics have widespread use in today’s sensor and actuator technologies. However, most commercially available piezoelectric materials, e.g., Pb [ZrxTi1-x] O3 (PZT,are comprised of more than 60 weight percent lead (Pb. Dueto its harmful effects, there is a strong impetus to identify new lead-free replacement materials with comparable properties to those of PZT. This review highlights recent developments in several lead-free piezoelectric materials including BaTiO3, Na0.5Bi0.5TiO3, K0.5Bi0.5TiO3, Na0.5K0.5NbO3, and their solid solutions. The factors that contribute to strong piezoelectric behavior are described and a summary of the properties for the various systems is provided.

Piezoelectric properties and diffusion phase transition around PPT of La-doped (Na{sub 0.52}K{sub 0.44}Li{sub 0.04}) Nb{sub 0.8}Ta{sub 0.2}O{sub 3} lead-free piezoelectric ceramics

Energy Technology Data Exchange (ETDEWEB)

Yang, Wenlong, E-mail: yangwenlong1983@163.com; Wang, Li; Li, Haidong; Han, Junsheng; Xiu, Hanjiang; Zhou, Zhongxiang

2016-10-01

Lead-free ceramics (Na{sub 0.52}K{sub 0.44}Li{sub 0.04}){sub 1−3x}La{sub x}Nb{sub 0.8}Ta{sub 0.2}O{sub 3} (KNLNT-Lax, x=0.00, 0.25, 0.5, 0.75, 1.00, 1.25 mol%) as non-polluting materials were prepared by solid state reaction method. The structure, piezoelectric proprieties and temperature stability of KNLNT ceramic with different La doping concentrations were investigated. The results show a transition from orthorhombic-tetragonal mix phase to tetragonal single phase with the variation of La{sup 3+} concentrations. The SEM micrographs of surface and fractured surface show a dense microstructure with few micropores. The La-doped KNLTN ceramic will be an alternative candidate contributes to excellent piezoelectric properties, which are found in the 0.75 mol% La-doped KNLNT ceramics, with d{sub 33}=215pC/N, k{sub p}=42.8%and Q{sub m}=89. It has been remarkably improved that the temperature stability of KNLTN-Lax piezoelectric properties at room temperature, and the dielectric relaxation can be observed obviously. The mechanism of La doping was analyzed in terms of valence compensation and polymorphic phase transition (PPT) diffusion. The orthorhombic-tetragonal phase transition around room temperature and the relaxation transition were considered contributing to the excellent piezoelectric performance and improved temperature stability of La{sup 3+}-doped KNLTN.

Processing and characterization of lead-free ceramics on the base of sodium-potassium niobate

Science.gov (United States)

Politova, E. D.; Golubko, N. V.; Kaleva, G. M.; Mosunov, A. V.; Sadovskaya, N. V.; Stefanovich, S. Yu.; Kiselev, D. A.; Kislyuk, A. M.; Panda, P. K.

Lead-free sodium-potassium niobate-based piezoelectric materials are most intensively studied in order to replace the widely used Pb-based ones. In this work, the effects of modification of compositions by donor and acceptor dopants in the A- and B-sites of perovskite lattice on structure, dielectric, ferroelectric, and piezoelectric properties of ceramics from Morphotropic Phase Boundary in the (1-x)(K0.5Na0.5)NbO3-xBaTiO3 system and in compositions with x=0.05 and 0.06 additionally doped by Ni3+ cations have been studied.

Processing and characterization of lead-free ceramics on the base of sodium–potassium niobate

Directory of Open Access Journals (Sweden)

E. D. Politova

2018-02-01

Full Text Available Lead-free sodium–potassium niobate-based piezoelectric materials are most intensively studied in order to replace the widely used Pb-based ones. In this work, the effects of modification of compositions by donor and acceptor dopants in the A- and B-sites of perovskite lattice on structure, dielectric, ferroelectric, and piezoelectric properties of ceramics from Morphotropic Phase Boundary in the (1−x(K0.5Na0.5NbO3–xBaTiO3 system and in compositions with x=0.05 and 0.06 additionally doped by Ni3+ cations have been studied.

Determination of temperature dependence of piezoelectric coefficients matrix of lead zirconate titanate ceramics by quasi-static and resonance method

International Nuclear Information System (INIS)

Li Fei; Xu Zhuo; Wei Xiaoyong; Yao Xi

2009-01-01

The piezoelectric coefficients (d 33 , -d 31 , d 15 , g 33 , -g 31 , g 15 ) of soft and hard lead zirconate titanate ceramics were measured by the quasi-static and resonance methods, at temperatures from 20 to 300 0 C. The results showed that the piezoelectric coefficients d 33 , -d 31 and d 15 obtained by these two methods increased with increasing temperature for both hard and soft PZT ceramics, while the piezoelectric coefficients g 33 , -g 31 and g 15 decreased with increasing temperature for both hard and soft PZT ceramics. In this paper, the observed results were also discussed in terms of intrinsic and extrinsic contributions to piezoelectric response.

Field-induced strain and polarization response in lead-free Bi1/2(Na0.80K0.20)1/2TiO3–SrZrO3 ceramics

International Nuclear Information System (INIS)

Hussain, Ali; Rahman, Jamil Ur; Zaman, Arif; Malik, Rizwan Ahmed; Kim, Jin Soo; Song, Tae Kwon; Kim, Won Jeong; Kim, Myong Ho

2014-01-01

The structure, field-induced strain, polarization and dielectric response of lead-free SrZrO 3 -modified Bi 1/2 (Na 0.80 K 0.20 ) 1/2 TiO 3 (abbreviated as BNKT–SZ100x, with x = 0–0.05) ceramics were investigated. The X-ray diffraction analysis of BNKT–SZ100x ceramics reveals no remarkable change in the crystal structure within the studied composition range. Around critical composition (x = 0.03) at a driving field of 6 kV mm −1 , large unipolar strain of 0.37% (S max /E max = 617) was obtained at room temperature. The ferroelectric and piezoelectric properties of BNKT ceramics were significantly increased at 2 mol%. At x = 0.02, remnant polarization reached a maximum value of 34 μC cm −2 , while the piezoelectric constant (d 33 ) attained maximum value of 190 pC/N. These results indicate that BNKT–SZ100x ceramics can be considered as promising candidate materials for lead-free piezoelectric actuator applications. - Highlights: • BNKT–SZ ceramics were synthesized by a conventional solid state reaction process. • Field-induced strain and piezoelectric constant were increased at critical composition. • BNKT–SZ100x ceramics at x = 0.03 exhibit a large field induced dynamic piezoelectric coefficient. • BNKT–SZ100x ceramics at x = 0.02 exhibit a high static piezoelectric constant. • The depolarization temperature of BNKT–SZ100x ceramics decrease with increase in SZ content

Effect of composition on electrical properties of lead-free Bi{sub 0.5}(Na{sub 0.80}K{sub 0.20}){sub 0.5}TiO{sub 3}-(Ba{sub 0.98}Nd{sub 0.02})TiO{sub 3} piezoelectric ceramics

Energy Technology Data Exchange (ETDEWEB)

Jaita, Pharatree [Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Watcharapasorn, Anucha; Jiansirisomboon, Sukanda [Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Materials Science Research Center, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand)

2013-07-14

Lead-free piezoelectric ceramics with the composition of (1-x)Bi{sub 0.5}(Na{sub 0.80}K{sub 0.20}){sub 0.5}TiO{sub 3}-x(Ba{sub 0.98}Nd{sub 0.02})TiO{sub 3} or (1-x) BNKT-xBNdT (with x = 0-0.20 mol fraction) have been synthesized by a conventional mixed-oxide method. The compositional dependence of phase structure and electrical properties of the ceramics were systemically studied. The optimum sintering temperature of all BNKT-BNdT ceramics was found to be 1125 Degree-Sign C. X-ray diffraction pattern suggested that BNdT effectively diffused into BNKT lattice during sintering to form a solid solution with a perovskite structure. Scanning electron micrographs showed a slight reduction of grain size when BNdT was added. It was found that BNKT-0.10BNdT ceramic exhibited optimum electrical properties ({epsilon}{sub r} = 1716, tan{delta} = 0.0701, T{sub c} = 327 Degree-Sign C, and d{sub 33} = 211 pC/N), suggesting that this composition has a potential to be one of a promising lead-free piezoelectric candidate for dielectric and piezoelectric applications.

Determination of temperature dependence of piezoelectric coefficients matrix of lead zirconate titanate ceramics by quasi-static and resonance method

Energy Technology Data Exchange (ETDEWEB)

Li Fei; Xu Zhuo; Wei Xiaoyong; Yao Xi, E-mail: lifei1216@gmail.co [Electronic Materials Research Laboratory, Key Laboratory of the Ministry of Education, Xi' an Jiaotong University, Xi' an 710049 (China)

2009-05-07

The piezoelectric coefficients (d{sub 33}, -d{sub 31}, d{sub 15}, g{sub 33}, -g{sub 31}, g{sub 15}) of soft and hard lead zirconate titanate ceramics were measured by the quasi-static and resonance methods, at temperatures from 20 to 300 {sup 0}C. The results showed that the piezoelectric coefficients d{sub 33}, -d{sub 31} and d{sub 15} obtained by these two methods increased with increasing temperature for both hard and soft PZT ceramics, while the piezoelectric coefficients g{sub 33}, -g{sub 31} and g{sub 15} decreased with increasing temperature for both hard and soft PZT ceramics. In this paper, the observed results were also discussed in terms of intrinsic and extrinsic contributions to piezoelectric response.

Piezoelectric Ceramics of the (1 − x)Bi0.50Na0.50TiO3–xBa0.90Ca0.10TiO3 Lead-Free Solid Solution: Chemical Shift of the Morphotropic Phase Boundary, a Case Study for x = 0.06

Science.gov (United States)

Vivar-Ocampo, Rodrigo; Pardo, Lorena; Ávila, David; Morán, Emilio; González, Amador M.; Bucio, Lauro; Villafuerte-Castrejón, María-Elena

2017-01-01

Research and development of lead-free piezoelectric materials are still the hottest topics in the field of piezoelectricity. One of the most promising lead-free family of compounds to replace lead zirconate–titanate for actuators is that of Bi0.50Na0.50TiO3 (BNT) based solid solutions. The pseudo-binary (1 − x)Bi0.50Na0.50TiO3–xBa1 − yCayTiO3 system has been proposed for high temperature capacitors and not yet fully explored as piezoelectric material. In this work, the solid solution with x = 0.06 and y = 0.10 was obtained by two different synthesis routes: solid state and Pechini, aiming at using reduced temperatures, both in synthesis (<800 °C) and sintering (<1150 °C), while maintaining appropriated piezoelectric performance. Crystal structure, ceramic grain size, and morphology depend on the synthesis route and were analyzed by X-ray diffraction, together with scanning and transmission electron microscopy. The effects of processing and ceramic microstructure on the structural, dielectric, ferroelectric, and piezoelectric properties were discussed in terms of a shift of the Morphotropic Phase Boundary, chemically induced by the synthesis route. PMID:28773096

Highly textured KNN-based piezoelectric ceramics by conventional sintering

International Nuclear Information System (INIS)

Zapata, Angelica Maria Mazuera; Silva Junior, Paulo Sergio da; Zambrano, Michel Venet

2016-01-01

Full text: Texturing in ferroelectric ceramics has played an important role in the enhancement of their piezoelectric properties. Common methods for ceramic texturing are hot pressing and template grain ground; nevertheless, the needed facilities to apply hot pressing and the processing of single crystal make the texture of ceramics expensive and very difficult. In this study, a novel method was investigated to obtain highly textured lead-free ceramics. A (K 0.5 Na 0.5 ) 0.97 Li 0. 0 3 Nb 0.8 Ta 0. 2 matrix (KNLNT), with CuO excess was sintered between 1070 and 1110 °C following a solid state reaction procedure. The CuO excess promotes liquid phase formation and a partial melting of the material. XRD patterns showed the intensity of (100) family peaks became much stronger with the increasing of sintering temperature and CuO. In addition, Lotgering factor was calculated and exhibited a texture degree between 40 % and 70 % for sintered samples having 13 and 16 wt. % CuO, respectively. These, highly textured ceramics, with adequate cut, can be used as substitutes single crystals for texturing of KNN-based lead-free ceramics. (author)

First-principles calculation of the effects of Li-doping on the structure and piezoelectricity of (K0.5Na0.5)NbO3 lead-free ceramics.

Science.gov (United States)

Yang, D; Wei, L L; Chao, X L; Yang, Z P; Zhou, X Y

2016-03-21

The crystal structures of the lead-free piezoelectric ceramics (K0.5Na0.5)NbO3 and (K0.5Na0.5)0.94Li0.06NbO3 prepared by a solid-state method were investigated using first-principles calculations. The calculated values of piezoelectricity were in good agreement with the experimental data. We found that the primary contribution to piezoelectricity in this material comes from the hybridization of the O 2p and Nb 4d orbitals, which causes a change in the Nb-O bond length and the distortion of the Nb-O octahedral structure. Analysis of the band structure and the total density of states revealed that Li-doped (K0.5Na0.5)NbO3 enhances hybridization of the O 2p and Nb 4d orbitals. This hybridization enhancement further reduces the Nb-O1 bond length and enhances the distortion of the Nb-O octahedron along the [001] direction, which may be the main reason for the improvement of the piezoelectric properties. In addition, the piezoelectric coefficients are calculated here, which show the same trend as the experimental results.

Structure and electrical properties of (1 − x) (Na0.5Bi0.5)0.94Ba0.06TiO3–x BiAlO3 lead-free piezoelectric ceramics

International Nuclear Information System (INIS)

Fu, Peng; Xu, Zhijun; Chu, Ruiqing; Wu, Xueyan; Li, Wei; Li, Xiaodong

2013-01-01

Highlights: ► (1 − x) BNBT6–x BA ceramics were prepared by solid-state reaction method. ► Electrical properties of BNBT6 ceramics are improved by the addition of BA. ► (1 − x) BNBT6 - x BA ceramics at x = 0.0225 have the best electrical properties. - Abstract: (1 − x) (Na 0.5 Bi 0.5 ) 0.94 Ba 0.06 TiO 3 –x BiAlO 3 ((1 − x) BNBT6–x BA) lead-free piezoelectric ceramics were synthesized by conventional solid-state processes. Effects of BiAlO 3 (BA) on the structure and electrical properties of (Na 0.5 Bi 0.5 ) 0.94 Ba 0.06 TiO 3 (BNBT6) ceramics were investigated. X-ray diffraction (XRD) data shows that (1 − x) BNBT6–x BA ceramics form the pure perovskite phases, and the ceramics have the morphotropic phase boundary (MPB) when x r = 42.5 μC/cm 2 ), the highest piezoelectric coefficient (d 33 = 204 pC/N), the highest planar coupling factor (k p = 0.3292), the highest dielectric constant (ε r = 1687) and higher mechanical quality factor (Q m = 112)

An ultrasonic therapeutic transducers using lead-free Na{sub 0.5}K{sub 0.5}NbO{sub 3}-CuNb{sub 2}O{sub 6} ceramics

Energy Technology Data Exchange (ETDEWEB)

Yang, Ming-Ru [Department of Electrical Engineering, National Cheng Kung University, Taiwan (China); Chu, Sheng-Yuan, E-mail: chusy@mail.ncku.edu.t [Department of Electrical Engineering, National Cheng Kung University, Taiwan (China); Advanced Optoelectronic Technology Center, National Cheng Kung University, Tainan 701, Taiwan (China); Institute of Nanotechnology and Microsystems Engineering, National Cheng Kung University, Tainan 701, Taiwan (China); Tsai, Cheng-Che [Department of Electronics Engineering and Computer Science, Tung-Fang Institute of Technology, Kaohsiung 829, Taiwan (China)

2010-10-08

Research highlights: {yields} In this paper, CN was added to NKN ceramics to decrease the sintering temperature and to improve the density and piezoelectric characteristics. The influence of CuNb{sub 2}O{sub 6} (CN) content on the microstructure, electrical properties, temperature stability, and mechanical properties of the synthesized samples was investigated. Results show that the samples synthesized with CN-doped not only improved the density but also exhibited superior piezoelectric characteristic, temperature stability of resonance frequency (TCF), and elastic stiffness coefficient than those of pure NKN piezoelectric ceramics. {yields} The bulk density (4.47 g/cm{sup 3}), k{sub p} (40%), k{sub t} (45%), Q{sub m} (1642), C{sub 33}{sup D} (19.64 x 10{sup 10} N/m{sup 2}), TCF (-0.011%/{sup o}C) and TCC (0.135%/{sup o}C) values for NKN-01CN ceramics obtained from experiments show excellent 'hard' piezoelectric properties. Furthermore, a lead-free NKN-01CN ultrasonic therapeutic transducer was successfully driven by a self-tuning circuit. - Abstract: In this work, we reports on the CuNb{sub 2}O{sub 6} (CN) modified lead-free Na{sub 0.5}K{sub 0.5}NbO{sub 3} (NKN) based piezoelectric ceramics were synthesized by solid-state reaction methods and sintered at 1075 {sup o}C for 3 h. A secondary phase of K{sub 4}CuNb{sub 8}O{sub 23} was found in the XRD pattern of NKN-based ceramics as the CN dopants is 1 mol%. Microstructural analyses of un-doped and CN-doped ceramics were performed in a scanning electron microscope. The influence of CN content on the microstructure, electrical properties, temperature stability, and mechanical properties of the synthesized ceramics was investigated. The results show that the synthesized ceramics with CN-doped not only had improved density but also exhibited superior piezoelectric characteristics, temperature stability of resonance frequency (TCF), and a better elastic stiffness coefficient than those of pure NKN piezoelectric

Finite element analysis of vibration energy harvesting using lead-free piezoelectric materials: A comparative study

Directory of Open Access Journals (Sweden)

Anuruddh Kumar

2014-06-01

Full Text Available In this article, the performance of various piezoelectric materials is simulated for the unimorph cantilever-type piezoelectric energy harvester. The finite element method (FEM is used to model the piezolaminated unimorph cantilever structure. The first-order shear deformation theory (FSDT and linear piezoelectric theory are implemented in finite element simulations. The genetic algorithm (GA optimization approach is carried out to optimize the structural parameters of mechanical energy-based energy harvester for maximum power density and power output. The numerical simulation demonstrates the performance of lead-free piezoelectric materials in unimorph cantilever-based energy harvester. The lead-free piezoelectric material K0.5Na0.5NbO3-LiSbO3-CaTiO3 (2 wt.% has demonstrated maximum mean power and maximum mean power density for piezoelectric energy harvester in the ambient frequency range of 90–110 Hz. Overall, the lead-free piezoelectric materials of K0.5Na0.5NbO3-LiSbO3 (KNN-LS family have shown better performance than the conventional lead-based piezoelectric material lead zirconate titanate (PZT in the context of piezoelectric energy harvesting devices.

Effect of B-site substitution of complex ions on dielectric and piezoelectric properties in (Bi1/2Na1/2)TiO3 piezoelectric ceramics

International Nuclear Information System (INIS)

Zhou Changrong; Liu Xinyu

2008-01-01

The effect of B-site substitution of complex ions on dielectric and piezoelectric properties in (Bi 1/2 Na 1/2 )Ti 1-x (Zn 1/3 Nb 2/3 ) x O 3 (BNTZN-100x) lead-free piezoelectric ceramics was investigated. X-ray diffraction analysis shows that the materials are mono-perovskite phase. The morphotropic phase boundary (MPB) of BNTZN-100x ceramics between rhombohedral and tetragonal locates in the range of 0.5% ≤ x ≤ 2.0%. Temperature dependence of dielectric constant shows that these compounds are relaxor ferroelectrics. The compositions near the MPB exhibit relatively high piezoelectric properties. The piezoelectric constant (d 33 ) and the electromechanical coupling factor (k t ) show the maximum values of d 33 = 97 pC N -1 and k t = 0.46 at x = 2.0% and x = 1.0%, respectively. The BNTZN-100x ceramics are good candidate for use as ultrasonic transducer ceramics for high anisotropic with high k t value and low k p value

A brief review of Ba(Ti0.8Zr0.2)O3-(Ba0.7Ca0.3)TiO3 based lead-free piezoelectric ceramics: Past, present and future perspectives

Science.gov (United States)

Zhang, Yong; Sun, Huajun; Chen, Wen

2018-03-01

As one kind of most crucial and emerging lead-free piezoelectric systems, Ba(Ti0.8Zr0.2)O3-(Ba0.7Ca0.3)TiO3 (BCZT) based lead-free piezoceramics have attracted worldwide attention in recent years. Much progress has been made, however, a summary which covers both the recent progress and the remained problems is urgently needed to further push this field forward. In this review, a brief background of the development of BCZT based lead-free piezoceramics was illustrated firstly. Then, the internal mechanism for the high piezoelectric response would be elaborated. Current research status was discussed in detail in the third section. Various strategies including: (1) Using distinct synthesis routes, (2) adopting different sintering techniques, (3) doping with foreign ions and/or second components, (4) grain size control, were exploited to improve the comprehensive performance and in turn broaden their application areas. In this part, some recently representative works were touched in detail and several existing problems were pointed out. Last, some critical comments (some thoughts related to the potential and future development of BCZT system) were given based on the current research status and existing problems. All in all, this review is devoted to summarizing the milestones in the past, classifying selected recent works and analyzing the prospects of BCZT based ceramics. It can be expected that, this first review that concentrates on BCZT based ceramics obviously would provide useful guidance for the research community.

Ferroelectric and dielectric properties of Sr2-x(Na, K)xBi4Ti5O18 lead-free piezoelectric ceramics

International Nuclear Information System (INIS)

Chen Qian; Xu Zhijun; Chu Ruiqing; Hao Jigong; Zhang Yanjie; Li Guorong; Yin Qingrui

2010-01-01

(Na, K)-doped Sr 2 Bi 4 Ti 5 O 18 (SBTi) bismuth layer structure ferroelectric ceramics were prepared by the solid-state reaction method. Pure bismuth-layered structural Sr 2-x (Na, K) x Bi 4 Ti 5 O 18 (x=0.1, 0.2, 0.3, and 0.4) ceramics with uniform grain size were obtained in this work. The effects of (Na, K)-doping on the dielectric, ferroelectric and piezoelectric properties of SBTi ceramics were investigated. Results showed that (Na, K)-doping caused the Curie temperature of SBTi ceramics to shift to higher temperature and enhanced the ferroelectric and piezoelectric properties. At x=0.2, the ceramics exhibited optimum properties with d 33 =20 pC/N, P r =10.3 μC/cm 2 , and T c =324 o C.

LEAD-FREE BNKT PIEZOELECTRIC ACTUATOR

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A. Moosavi

2016-03-01

Full Text Available An actuator is a device that converts input energy into mechanical energy. According to various types of input energy, various actuators have been advanced. Displacement in the electromagnetic, hydraulic and pneumatic actuators achieve by moving a piston via electromagnetic force or pressure, however the piezoelectric actuator (piezoceramic plates displace directly. Therefore, accuracy and speed in the piezoelectric device are higher than other types of actuators. In the present work, the high-field electromechanical response of high-quality (1−x(Bi 0.5Na0.5TiO3–x(Bi0.5K0.5TiO3 samples abbreviated to BNKTx with x = 0.18, 0.20, 0.22 and 0.24 ceramic materials across its MPB was investigated. The piezoelectrics and actuation characteristics were characterized. Ourresults indicate that x = 0.20, indeed, constitutes the best choice for the MPB composition in the system. Maximum of remanent polarization (37.5 μC cm−2 was obtained for x=0.20. High-field electromechanical responses were also obtained for BNKT0.20 samples. This material exhibited giant field induced strains of 0.13% under 1 kV mm -1 at room temperature.

Ferroelectric and impedance response of lead-free (B/sub o.5/N/sub 0.5/)TiO/sub 3/-BaZrO/sub 3/ piezoelectric ceramics

International Nuclear Information System (INIS)

Rehman, J. U.; Hussain, A.; Maqbool, A.; Kim, J. S.; Song, T. K.; Lee, J. H.; Kim, W. J.; Kim, M. H.

2013-01-01

Lead-free piezoelectric (0.96B/sub 0.5/N/sub 0.5/TiO/sub 3/)-0.04BaZrO/sub 3/ (BNT-BZ4) was synthesized by using a solid-state reaction method. SEM micrograph shows dense microstructure. X-ray diffraction (XRD) indicated the formation of a BNB-BZ4 single phase having pseudocubic symmetry. A maximum value of remnant polarization (30 meuC/cm2) and piezoelectric constant (112 pC/N) was observed for BNT-BZ4 ceramic. The temperature dependences of the dielectric properties of BNT-BZ4 were investigated in the temperature range of 25-600 degree C at various frequencies (0.1 Hz-1 MHz). The maximum dielectric constant value (epsilonr) reaches a highest value of 4046 (at 10 kHz). The electrical properties were investigated by using complex impedance spectroscopy and provided better understanding of relaxation process. (author)

Polymer-ceramic piezoelectric composites (PZT)

International Nuclear Information System (INIS)

Bassora, L.A.; Eiras, J.A.

1992-01-01

Polymer-ceramic piezoelectric transducers, with 1-3 of connectivity were prepared with different concentration of ceramic material. Piezoelectric composites, with equal electromechanical coupling factor and acoustic impedance of one third from that ceramic transducer, were obtained when the fractionary volume of PZT reach 30%. (C.G.C.)

Giant Piezoelectricity and High Curie Temperature in Nanostructured Alkali Niobate Lead-Free Piezoceramics through Phase Coexistence.

Science.gov (United States)

Wu, Bo; Wu, Haijun; Wu, Jiagang; Xiao, Dingquan; Zhu, Jianguo; Pennycook, Stephen J

2016-11-30

Because of growing environmental concerns, the development of lead-free piezoelectric materials with enhanced properties has become of great interest. Here, we report a giant piezoelectric coefficient (d 33 ) of 550 pC/N and a high Curie temperature (T C ) of 237 °C in (1-x-y)K 1-w Na w Nb 1-z Sb z O 3- xBiFeO 3- yBi 0.5 Na 0.5 ZrO 3 (KN w NS z -xBF-yBNZ) ceramics by optimizing x, y, z, and w. Atomic-resolution polarization mapping by Z-contrast imaging reveals the intimate coexistence of rhombohedral (R) and tetragonal (T) phases inside nanodomains, that is, a structural origin for the R-T phase boundary in the present KNN system. Hence, the physical origin of high piezoelectric performance can be attributed to a nearly vanishing polarization anisotropy and thus low domain wall energy, facilitating easy polarization rotation between different states under an external field.

Applications of Piezoelectric Ceramics

Indian Academy of Sciences (India)

Applications of Piezoelectric Ceramics. Piezoelectric Actuators. Nano and Micropositioners. Vibration Control Systems. Computer Printers. Piezoelectric Transformers,Voltage Generators, Spark Plugs, Ultrasonic Motors,. Ultrasonic Generators and Sensors. Sonars, Medical Diagnostic. Computer Memories. NVFRAM ...

Piezoelectric displacement in ceramics

International Nuclear Information System (INIS)

Stewart, M.; Cain, M.; Gee, M.

1999-01-01

This Good Practice Guide is intended to aid a user to perform displacement measurements on piezoelectric ceramic materials such as PZT (lead zirconium titanate) in either monolithic or multilayer form. The various measurement issues that the user must consider are addressed, and good measurement practise is described for the four most suitable methods. (author)

Phase segregation and dielectric, ferroelectric, and piezoelectric properties of MgO-doped NBT-BT lead-free ferroelecric ceramics

Science.gov (United States)

Liu, Gang; Wang, Ziyang; Zhang, Leiyang; Shi, Wenjing; Jing, Jiayi; Chen, Yi; Liu, Hongbo; Yan, Yan

2018-03-01

MgO doped NBT-BT ceramics were prepared by the conventional electroceramic processing. The effects of MgO on the phase, microstructures and electrical properties of NBT-BT ceramics were systematically investigated. When doping content is more than 1%, a second phase appeared, which has great effect on dielectric, ferroelectric, and piezoelectric properties, such as the T F-R peak weakened, moved to the higher temperature, and eventually disappeared. When the doping content is above 1.5%, the ceramic samples show a strong relaxation. The detailed analysis and discussion can be found within this study.

Effect of ZnO-B{sub 2}O{sub 3} addition on the dielectric and the piezoelectric properties of lead-free (Na{sub 0.525}K{sub 0.443}Li{sub 0.037})(Nb{sub 0.883}Sb{sub 0.08}Ta{sub 0.037})O{sub 3} ceramics

Energy Technology Data Exchange (ETDEWEB)

Kim, You-Seok; Yoo, Ju-Hyun [Semyung University, Jecheon (Korea, Republic of)

2014-12-15

(Na{sub 0.525}K{sub 0.443}Li{sub 0.037})(Nb{sub 0.883}Sb{sub 0.08}Ta{sub 0.037})O{sub 3} + x wt% ZnO-B{sub 2}O{sub 3} (NKLNST + x ZnO-B{sub 2}O{sub 3}) lead-free piezoelectric ceramics were prepared via a conventional solid-state reaction for various values of x = 0, 0.3, 0.6, 0.9, 1.2; then, the dielectric and the piezoelectric properties of these ceramics were investigated. A pure perovskite structure and a small secondary phase were observed in the X-ray diffraction patterns. For the 0.3-wt% ZnO-B{sub 2}O{sub 3} specimen, a density of ρ = 4.537 g/cm{sup 3}, an electromechanical coupling factor of k{sub P} = 0.432, a mechanical quality factor of Q{sub m} = 96, and piezoelectric constant of d{sub 33} = 209 pC/N were found to be optimal. These results indicate that the material with this composition is a promising candidate for use in a lead-free piezoelectric device.

Piezoelectric ceramic-reinforced metal matrix composites

OpenAIRE

2004-01-01

Composite materials comprising piezoelectric ceramic particulates dispersed in a metal matrix are capable of vibration damping. When the piezoelectric ceramic particulates are subjected to strain, such as the strain experienced during vibration of the material, they generate an electrical voltage that is converted into Joule heat in the surrounding metal matrix, thereby dissipating the vibrational energy. The piezoelectric ceramic particulates may also act as reinforcements to improve the mec...

FABRICATION AND MECHANICAL PROPERTIES OF Na0.5Bi0.5TiO3–BaTiO3 LEAD-FREE PIEZOELECTRIC CERAMICS

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PAN YUSONG

2014-03-01

Full Text Available Piezoelectric ceramics with 0.94Na0.5Bi0.5TO3–0.06BaTiO3 compositions were fabricated by solid state mixed oxide method and sintered at different temperatures varying from 1050°C to 1150°C to obtain dense ceramics. Phase analysis using X-ray diffraction showed tetragonal perovskite structure of Na0.5Bi0.5TO3 with no BaTiO3 peak detected. The SEM observation revealed that the crystal grain size of the piezoelectric ceramics is on the nano-size dimensions under all the sintering temperature. The study on the compressive mechanical characteristics showed that the compressive strength of the 0.94Na0.5Bi0.5TO3–0.06BaTiO3 piezoelectric ceramics increases with the rise of sintering temperature and sintering time. The change behavior of the compressive strength with the rise of cold pressure presents increasing firstly and then decreases.

Investigation of structural, ferroelectric, piezoelectric and dielectric properties of Ba0.92Ca0.08TiO3-BaTi0.96Zr0.04O3 lead-free electroceramics

Science.gov (United States)

Keswani, Bhavna C.; Patil, S. I.; Kolekar, Y. D.

2018-04-01

Lead free ferroelectric with composition 0.55Ba0.92Ca0.08TiO3-0.45BaTi0.96Zr0.04O3 (BCT8-BZT4) was synthesized by solid state reaction method and investigated their structural, ferroelectric, piezoelectric and dielectric properties. X-ray diffraction analysis shows that BCT8-BZT4 ceramic possess both tetragonal (space group P4mm) and orthorhombic (space group Amm2) crystal structure which was further confirmed from Raman spectra spectroscopy. The micronized grains were observed from scanning electron micrographs while the presence of polarization-electric field hysteresis loop confirms ferroelectric nature of BCT8-BZT4 ceramic. Higher values of maximum polarization (Pmax = 22.27 μC/cm2), remnant polarization (Pr = 11.61 μC/cm2), coercive electric field (Ec = 4.77 kV/cm) and direct piezoelectric coefficient (d33) approximately 185 pC/N were observed. The real part of dielectric constant with frequency shows the usual dielectric dispersion behaviour at RT. The observed properties show that the lead free BCT8-BZT4 ceramic is suitable for ferroelectric memory device, piezoelectric sensor, capacitor, etc. applications.

Phase transition and piezoelectric properties of K0.48Na0.52NbO3-LiTa0.5Nb0.5O3-NaNbO3 lead-free ceramics

International Nuclear Information System (INIS)

Gao Feng; Liu Liangliang; Xu Bei; Cao Xiao; Deng Zhenqi; Tian Changsheng

2011-01-01

Highlights: → The evolution of the crystal structure for the new phase K 3 Li 2 Nb 5 O 15 was described. → The dielectric relaxor behavior would be strengthened by increasing plate-like NN. → k p and d 33 decrease with increasing amount of plate-like NN. → 0.01-0.03 mol of plate-like NN is a proper content for texturing ceramics by RTGG. - Abstract: Plate-like NaNbO 3 (NN) particles were used as the raw material to fabricate (1 - x)[0.93 K 0.48 Na 0.52 Nb O 3 -0.07Li(Ta 0.5 Nb 0.5 )O 3 ]-xNaNbO 3 lead-free piezoelectric ceramics using a conventional ceramic process. The effects of NN on the crystal structure and piezoelectric properties of the ceramics were investigated. The results of X-ray diffraction suggest that the perovskite phase coexists with the K 3 Li 2 Nb 5 O 15 phase, and the tilting of the oxygen octahedron is probably responsible for the evolution of the tungsten-bronze-typed K 3 Li 2 Nb 5 O 15 phase. The Curie temperature (T C ) is shifted to lower temperature with increasing NN content. (1 - x)[0.93 K 0.48 Na 0.52 NbO 3 -0.07Li(Ta 0.5 Nb 0.5 )O 3 ]-xNaNbO 3 ceramics show obvious dielectric relaxor characteristics for x > 0.03, and the relaxor behavior of ceramics is strengthened by increasing NN content. Both the electromechanical coupling factor (k p ) and the piezoelectric constant (d 33 ) decrease with increasing amounts of NN. 0.01-0.03 mol of plate-like NaNbO 3 in 0.93 K 0.48 Na 0.52 NbO 3 -0.07Li(Ta 0.5 Nb 0.5 )O 3 gives the optimum content for preparing textured ceramics by the RTGG method.

Electromechanical characteristics of piezoelectric ceramic transformers in radial vibration composed of concentric piezoelectric ceramic disk and ring

International Nuclear Information System (INIS)

Lin, Shuyu; Hu, Jing; Fu, Zhiqiang

2013-01-01

A new type of piezoelectric ceramic transformer in radial vibration is presented. The piezoelectric transformer consists of a pairing of a concentric piezoelectric ceramic circular disk and ring. The inner piezoelectric ceramic disk is axially polarized and the outer piezoelectric ring is radially polarized. Based on the plane stress theory, the exact analytical theory for the piezoelectric transformer is developed and its electromechanical equivalent circuit is introduced. The resonance/anti-resonance frequency equations of the transformer are obtained and the relationship between the resonance/anti-resonance frequency, the effective electromechanical coupling coefficient and the geometrical dimensions of the piezoelectric transformer is analyzed. The dependency of the voltage transformation ratio on the frequency is obtained. To verify the analytical theory, a numerical method is used to simulate the electromechanical characteristics of the piezoelectric transformer. It is shown that the analytical resonance/anti-resonance frequencies are in good agreement with the numerical results. (paper)

Enhanced temperature stability and quality factor with Hf substitution for Sn and MnO2 doping of (Ba0.97Ca0.03(Ti0.96Sn0.04O3 lead-free piezoelectric ceramics with high Curie temperature

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Cheng-Che Tsai

2016-12-01

Full Text Available In this work, the process of two-stage modifications for (Ba0.97Ca0.03(Ti0.96Sn0.04-xHfxO3 (BCTS4-100xH100x ceramics was studied. The trade-off composition was obtained by Hf substitution for Sn and MnO2 doping (two-stage modification which improves the temperature stability and piezoelectric properties. The phase structure ratio, microstructure, and dielectric, piezoelectric, ferroelectric, and temperature stability properties were systematically investigated. Results showed that BCTS4-100xH100x piezoelectric ceramics with x=0.035 had a relatively high Curie temperature (TC of about 112 °C, a piezoelectric charge constant (d33 of 313 pC/N, an electromechanical coupling factor (kp of 0.49, a mechanical quality factor (Qm of 122, and a remnant polarization (Pr of 19μC/cm2. In addition, the temperature stability of the resonant frequency (fr, kp, and aging d33 could be tuned via Hf content. Good piezoelectric temperature stability (up to 110 °C was found with x =0.035. BCTS0.5H3.5 + a mol% Mn (BCTSH + a Mn piezoelectric ceramics with a = 2 had a high TC of about 123 °C, kp ∼ 0.39, d33 ∼ 230 pC/N, Qm ∼ 341, and high temperature stability due to the produced oxygen vacancies. This mechanism can be depicted using the complex impedance analysis associated with a valence compensation model on electric properties. Two-stage modification for lead-free (Ba0.97Ca0.03(Ti0.96Sn0.04O3 ceramics suitably adjusts the compositions for applications in piezoelectric motors and actuators.

Review and Perspectives of Aurivillius Structures as a Lead-Free Piezoelectric System

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Alberto Moure

2018-01-01

Full Text Available According to the EU-Directives 2002/95/EC, 2002/96/EC, lead-based piezoceramics must be substituted in the future with more environmentally friendly alternatives, only when a reliable alternative is found. This is why an increasing interest has grown in the research community to find lead free piezoelectric materials that fulfil the requirements for this substitution. Different families of compounds have been shown to be possible candidates for this use, such as bismuth and niobates based perovskites, pyrochlores, etc. However, a material with piezoelectric coefficients similar to those of PZT (lead zirconate titanate, Pb[ZrxTi1-x]O3 has not been yet found. Besides, each of these families has its specific characteristics in terms of remnant polarization, coercive field or application temperature. Thus, the choice of each material should be made according to the specific needs of the application. In this sense, Aurivillius-type structure materials (also known as Bismuth Layered Structure Ferroelectrics, BLSF can take advantage of their specific properties for uses as Lead Free Piezoelectric systems. Some of them have a high Curie temperature, which make them good candidates to be used as high temperature piezoelectrics; high coercive fields, which facilitates their use as actuators; or a high switching fatigue resistance, which can be useful for future applications as Ferroelectric Random Access Memories (FERAM.

Enhanced piezoelectric properties in vanadium-modified lead-free (K{sub 0.485}Na{sub 0.5}Li{sub 0.015})(Nb{sub 0.88}Ta{sub 0.1}V{sub 0.02})O{sub 3} ceramics prepared from nanopowders

Energy Technology Data Exchange (ETDEWEB)

Gaur, Roopam; Dhingra, Apurva; Pal, Soham; Chandramani Singh, K., E-mail: kongbam@gmail.com

2015-03-15

Highlights: • (K{sub 0.485}Na{sub 0.5}Li{sub 0.015})(Nb{sub 0.9−x}Ta{sub 0.1}V{sub x}) O{sub 3}(x = 0, 0.01, 0.02, 0.03) ceramics were prepared. • These ceramics were synthesized from 35-nm powders. • Density, microstrain, crystallite size, tetragonality were high at x = 0.02. • Dielectric, ferroelectric and piezoelectric properties were enhanced at x = 0.02. • The increased properties are attributed to crystal structure and microstructure. - Abstract: Enhancing the piezoelectric properties of lead-free piezoceramics like alkaline niobate system has been an important research topic in our search for an alternative to widely used but highly toxic lead-based PZT piezoceramics system. In the present study, lead-free alkaline niobate-based compositions (K{sub 0.485}Na{sub 0.5}Li{sub 0.015})(Nb{sub 0.9−x}Ta{sub 0.1}V{sub x})O{sub 3} (x = 0, 0.01, 0.02 and 0.03) were synthesized using conventional solid state reaction method. Nanocrystalline powders of these compositions, produced by high energy ball milling, were sintered at 1050 °C for 4 h to produce corresponding ceramics. Increasing V{sup 5+} content in the ceramics from x = 0 to 0.02 results in a gradual increase in the room temperature dielectric constant (ε{sub r}) from 1185 to 1336, remnant polarization (P{sub r}) from 13.4 μC/cm{sup 2} to 17.1 μC/cm{sup 2}, electromechanical coupling factor (k{sub p}) from 0.37 to 0.40, and piezoelectric charge constant (d{sub 33}) from 156 pC/N to 185 pC/N. Further increase in x to 0.03 lowers these values to 1082, 13.4 μC/cm{sup 2}, 0.36 and 128 pC/N respectively. Correspondingly, the coercive field (E{sub c}) first shows a gradual decline from 8.5 kV/cm to 7.9 kV/cm and then a rise to 9.2 kV/cm, as x increases from 0 to 0.02 and then to 0.03. The enhancement of piezoelectric properties in (K{sub 0.485}Na{sub 0.5}Li{sub 0.015})(Nb{sub 0.88}Ta{sub 0.1}V{sub 0.02})O{sub 3} ceramics is attributed to the associated higher values of density, tetragonality and

Fabrication and characterization of thick-film piezoelectric lead zirconate titanate ceramic resonators by tape-casting.

Science.gov (United States)

Qin, Lifeng; Sun, Yingying; Wang, Qing-Ming; Zhong, Youliang; Ou, Ming; Jiang, Zhishui; Tian, Wei

2012-12-01

In this paper, thick-film piezoelectric lead zirconate titanate (PZT) ceramic resonators with thicknesses down to tens of micrometers have been fabricated by tape-casting processing. PZT ceramic resonators with composition near the morphotropic phase boundary and with different dopants added were prepared for piezoelectric transducer applications. Material property characterization for these thick-film PZT resonators is essential for device design and applications. For the property characterization, a recently developed normalized electrical impedance spectrum method was used to determine the electromechanical coefficient and the complex piezoelectric, elastic, and dielectric coefficients from the electrical measurement of resonators using thick films. In this work, nine PZT thick-film resonators have been fabricated and characterized, and two different types of resonators, namely thickness longitudinal and transverse modes, were used for material property characterization. The results were compared with those determined by the IEEE standard method, and they agreed well. It was found that depending on the PZT formulation and dopants, the relative permittivities ε(T)(33)/ε(0) measured at 2 kHz for these thick-films are in the range of 1527 to 4829, piezoelectric stress constants (e(33) in the range of 15 to 26 C/m(2), piezoelectric strain constants (d(31)) in the range of -169 × 10(-12) C/N to -314 × 10(-12) C/N, electromechanical coupling coefficients (k(t)) in the range of 0.48 to 0.53, and k(31) in the range of 0.35 to 0.38. The characterization results shows tape-casting processing can be used to fabricate high-quality PZT thick-film resonators, and the extracted material constants can be used to for device design and application.

Giant strain with low cycling degradation in Ta-doped [Bi_1_/_2(Na_0_._8K_0_._2)_1_/_2]TiO_3 lead-free ceramics

International Nuclear Information System (INIS)

Liu, Xiaoming; Tan, Xiaoli

2016-01-01

Non-textured polycrystalline [Bi_1_/_2(Na_0_._8K_0_._2)_1_/_2](Ti_1_−_xTa_x)O_3 ceramics are fabricated and their microstructures and electrical properties are characterized. Transmission electron microscopy reveals the coexistence of the rhombohedral R3c and tetragonal P4bm phases in the form of nanometer-sized domains in [Bi_1_/_2(Na_0_._8K_0_._2)_1_/_2]TiO_3 with low Ta concentration. When the composition is x = 0.015, the electrostrain is found to be highly asymmetric under bipolar fields of ±50 kV/cm. A very large value of 0.62% is observed in this ceramic, corresponding to a large-signal piezoelectric coefficient d_3_3* of 1240 pm/V (1120 pm/V under unipolar loading). These values are greater than most previously reported lead-free polycrystalline ceramics and can even be compared with some lead-free piezoelectric single crystals. Additionally, this ceramic displays low cycling degradation; its electrostrain remains above 0.55% even after undergoing 10 000 cycles of ±50 kV/cm bipolar fields at 2 Hz. Therefore, Ta-doped [Bi_1_/_2(Na_0_._8K_0_._2)_1_/_2]TiO_3 ceramics show great potential for large displacement devices.

Effects of MnO{sub 2} doping on structure, dielectric and piezoelectric properties of 0.825NaNbO{sub 3}-0.175Ba{sub 0.6}(Bi{sub 0.5}K{sub 0.5}){sub 0.4}TiO{sub 3} lead-free ceramics

Energy Technology Data Exchange (ETDEWEB)

Fan, Ximing; Lin, Dunmin; Zheng, Qiaoji; Sun, Hailing; Wan, Yang; Wu, Xiaochun [College of Chemistry and Materials Science, and Visual Computing and Virtual Reality Key Laboratory of Sichuan Province, Sichuan Normal University, Chengdu 610066 (China); Wu, Lang [State Key Laboratory Cultivation Base for Nonmetal Composites and Functional Materials, Southwest University of Science and Technology, Mianyang 621010 (China)

2012-12-15

Lead-free ceramics 0.825NaNbO{sub 3}-0.175Ba{sub 0.6}(Bi{sub 0.5}K{sub 0.5}){sub 0.4}TiO{sub 3} + xmol% MnO{sub 2} were prepared by an ordinary sintering technique and the effects of MnO{sub 2} doping on the structure, dielectric, and piezoelectric properties of the ceramics were studied. The ceramics with perovskite structure are transformed from tetragonal to pseudocubic phases by increasing the doping level of MnO{sub 2}. After the addition of MnO{sub 2}, the Curie temperature T{sub C} of the ceramics decreases and the ferroelectric-paraelectric phase transition at T{sub C} becomes more diffusive. Because of the donor and acceptor doping effects of Mn ions simultaneously, the piezoelectric constant d{sub 33}, electromechanical coupling coefficient k{sub p}, relative permittivity {epsilon}{sub r}, and mechanical quality factor Q{sub m} are enhanced considerably after the addition of 1 mol% MnO{sub 2}. The ceramic with 1 mol% MnO{sub 2} doping possesses the optimum piezoelectricity (d{sub 33} = 131 pC/N and k{sub p} = 21.8%) and relatively high Q{sub m} = 627. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Piezoelectric properties of lead-free submicron-structured (Bi0.5Na0.5)0.94Ba0.06TiO3 ceramics from nanopowders

International Nuclear Information System (INIS)

Pardo, Lorena; García, Alvaro; Brebøl, Klaus; Mercadelli, Elisa; Galassi, Carmen

2010-01-01

Submicron-structured (Bi 0.5 Na 0.5 ) 0.94 Ba 0.06 TiO 3 (BNBT6) ceramics were obtained from nanometric powder synthesized by sol–gel auto-combustion at 500 °C. Hot-pressing at low temperatures and a combination of this with recrystallization, still moderate in order to reduce the loss of volatile elements, have been tested. Material properties, including all losses, were determined at the resonances of thin discs using Alemany et al software. Ceramics hot-pressed at 700–800 °C for 2 h have a pseudo-cubic structure, a grain size of a few hundred nanometers and are homogeneous. Both their crystal structure and the lack of sintering prevent their poling. For ceramics hot-pressed at 950 °C for 3 h, Bi or Bi 0.5 Na 0.5 loss, together with low piezoelectric properties (d 33 = 60 pC N −1 , k p = 8.3% and k t = 9.5%), was observed. Recrystallization at 1000 °C-1 h of ceramics hot-pressed at 700 and 800 °C for 2 h keeps the submicron structure, reduces porosity and prevents off-stoichiometry. Mechanical and piezoelectric losses are also reduced and coupling factors increased (k p = 24.6%, k t = 36.4%). The best piezoelectric coefficient obtained in these ceramics (d 33 = 143 pC N −1 ) is comparable with those reported for coarse-grained ceramics

Phase coexistence and high piezoelectric properties in (K0.40Na0.60)0.96Li0.04Nb0.80Ta0.20O3 ceramics

International Nuclear Information System (INIS)

Wu Ling; Zhang Jialiang; Shao Shoufu; Zheng Peng; Wang Chunlei

2008-01-01

Lead-free (K x Na 1-x ) 0.96 Li 0.04 Nb 0.80 Ta 0.20 O 3 ceramics with x = 0.10-0.70 were prepared by the conventional solid-state reaction technique. The influence of the K/Na ratio on the microstructure, crystallographic structure, phase transition and piezoelectric properties was investigated. It has been disclosed that the phase transition temperature T O-T drastically decreases with x in the narrow compositional range of x 0.30-0.40 and the phase coexistence of the orthorhombic structure and the tetragonal structure occurs near x = 0.40. The ceramics with x = 0.40 shows high piezoelectric properties (d 33 = 254 pC N -1 , k p = 51.5%, k t = 49.4% and k 33 = 66.6%, respectively) with low dielectric loss (tan δ 1.5%) and weak temperature dependence between 10 and 85 deg. C. In particular, the piezoelectric properties remain almost unchanged in the thermal ageing test from -125 to 300 deg. C. Therefore, this ceramic is considered to be a very promising lead-free piezoelectric material for practical applications. The relation of piezoelectric properties with morphotropic phase boundary and polymorphic phase transition was discussed

Effects of the co-addition of LiSbO3-LiTaO3 on the densification of (Na1/2K1/2)NbO3 lead free ceramics by atmosphere sintering

International Nuclear Information System (INIS)

Jiang Na; Fang Bijun; Wu Jian; Du Qingbo

2011-01-01

Research highlights: → This manuscript shows a synthesis method that can easily obtain excellent lead-free samples, which is valuable for industrial production. → Pure phase perovskite 0.94(Na 1/2 K 1/2 )NbO 3 -0.03LiSbO 3 -0.03LiTaO 3 (0.94NKN-0.03LS-0.03LT) lead-free piezoelectric ceramics with high relative density, being 94.73%, and excellent integral electrical properties, piezoelectric constant d 33 being 228 pC/N, were prepared by atmosphere sintering method. Which can be attributed to the co-doping of LiSbO 3 -LiTaO 3 . - Abstract: Pure phase perovskite 0.94(Na 1/2 K 1/2 )NbO 3 -0.03LiSbO 3 -0.03LiTaO 3 (0.94NKN-0.03LS-0.03LT) lead-free piezoelectric ceramics were prepared by the conventional solid-state reaction method. Due to the co-addition of LiSbO 3 -LiTaO 3 , the 0.94NKN-0.03LS-0.03LT ceramics prepared by atmosphere sintering at 1040 deg. C exhibit high relative density, being 94.73%, and rather homogenous microstructure. X-ray diffraction (XRD) measurement confirmed that the sintered ceramics exhibit pure tetragonal perovskite structure. The 0.94NKN-0.03LS-0.03LT ceramics exhibit excellent integral electrical properties, in which the value of piezoelectric constant d 33 is 228 pC/N, the electromechanical coupling factors K p and K t are 0.220 and 0.230, respectively, the mechanical quality factor Q m is 32.19, and the remnant polarization P r is 23.06 μC/cm 2 . Such excellent electrical properties are considered as correlating with the high relative density of the synthesized ceramics induced by the co-doping of LiSbO 3 -LiTaO 3 .

Piezoelectric and ferroelectric properties of lead-free niobium-rich potassium lithium tantalate niobate single crystals

Energy Technology Data Exchange (ETDEWEB)

Li, Jun, E-mail: lijuna@hit.edu.cn [Department of Physics, Harbin Institute of Technology, Harbin 150001 (China); Li, Yang [Department of chemistry, Harbin Institute of Technology, Harbin 150001 (China); Zhou, Zhongxiang [Department of Physics, Harbin Institute of Technology, Harbin 150001 (China); Guo, Ruyan; Bhalla, Amar S. [Multifunctional Electronic Materials and Device Research Lab, Department of Electrical and Computer Engineering, The University of Texas at San Antonio, San Antonio 78249 (United States)

2014-01-01

Graphical abstract: - Highlights: • Lead-free K{sub 0.95}Li{sub 0.05}Ta{sub 1−x}Nb{sub x}O{sub 3} single crystals were grown using the top-seeded melt growth method. • The piezoelectric and ferroelectric properties of as-grown crystals were systematically investigated. • The piezoelectric properties are very attractive, e.g. for x = 0.60 composition, k{sub t} ≈ 70%, k{sub 31} ≈ 70%, k{sub 33} ≈ 77%, d{sub 31} ≈ 230 pC/N, d{sub 33} ≈ 600 pC/N. • The coercive fields of P–E hysteresis loops are quite small, about or less than 1 kV/mm. - Abstract: Lead-free potassium lithium tantalate niobate single crystals with the composition of K{sub 0.95}Li{sub 0.05}Ta{sub 1−x}Nb{sub x}O{sub 3} (abbreviated as KLTN, x = 0.51, 0.60, 0.69, 0.78) were grown using the top-seeded melt growth method. Their piezoelectric and ferroelectric properties in as-grown crystals have been systematically investigated. The phase transitions and Curie temperatures were determined from dielectric and pyroelectric measurements. Piezoelectric coefficients and electromechanical coupling factors in thickness mode, length-extensional mode and longitudinal mode were obtained. The piezoelectric properties are very attractive, e.g. for x = 0.60 composition, k{sub t} ≈ 70%, k{sub 31} ≈ 70%, k{sub 33} ≈ 77%, d{sub 31} ≈ 230 pC/N, d{sub 33} ≈ 600 pC/N are comparable to the lead-based PZT composition. The polarization versus electric field hysteresis loops show saturated shapes. In short, lead-free niobium-rich KLTN system possesses comparable properties to those in important lead-based piezoelectric material nowadays.

Growth and characterization of lead-free (K,Na)NbO3-based piezoelectric single crystals

International Nuclear Information System (INIS)

Liu, Hairui

2016-01-01

Lead-free piezoelectric materials have received increasing attention in the last decade, driven by environmental issues and health concerns. Of considerable interest is the (K,Na)NbO 3 (KNN)-based system, which possesses a relatively high Curie temperature and good piezoelectric properties. Abundant publications on KNN-based polycrystalline ceramics increased the interest in studying their single-crystalline form, based on two major concerns. The first concern refers to the negative role of grain interactions on the electromechanical response. The second concern deals with domain engineering. The relationship between external electric field direction, crystallographic orientation, and spontaneous polarization vectors for a specific structure can be more readily established in single crystals and thus offers a pathway for an in-depth understanding of fundamental mechanism and potential applications. The exciting enhancement of both piezoelectric and ferroelectric response in lead-based single crystals also encourages the further exploration of KNN-based piezoelectric crystals, as they possess the same perovskite structure. The main goal of this thesis is to find possible approaches for improved electromechanical properties in KNN-based piezoelectric single crystals. In Chapter 2, the current development of KNN-based single crystals as piezoelectrics is reviewed, following a short introduction of fundamental knowledge on piezoelectrics and ferroelectrics. Both submerged-seed solution growth and top-seeded solution growth techniques were employed to produce single crystals, as described detailed in Chapter 3. Emphasis is subsequently placed on issues of the crystal growth process, effective methods to enhance electrical properties, and crystallographic orientation-dependent electrical properties in Li-, Ta-, and/or Sb-substituted KNN single crystals. The main conclusions from the crystal growth aspect are presented in Chapter 4 and can be summarized as follows: (i

Study on the sandwich piezoelectric ceramic ultrasonic transducer in thickness vibration

International Nuclear Information System (INIS)

Lin Shuyu; Tian Hua

2008-01-01

A sandwich piezoelectric ceramic ultrasonic transducer in thickness vibration is studied. The transducer consists of front and back metal masses, and coaxially segmented, thickness polarized piezoelectric ceramic thin rings. For this kind of sandwich piezoelectric transducers in thickness vibration, it is required that the lateral dimension of the transducer is sufficiently large compared with its longitudinal dimension so that no lateral displacements in the transducer can occur (laterally clamped). In this paper, the thickness vibration of the piezoelectric ceramic stack consisting of a number of identical piezoelectric ceramic thin rings is analysed and its electro-mechanical equivalent circuit is obtained. The resonance frequency equation for the sandwich piezoelectric ceramic ultrasonic transducer in thickness vibration is derived. Based on the frequency equation, two sandwich piezoelectric ceramic ultrasonic transducers are designed and manufactured, and their resonance frequencies are measured. It is shown that the measured resonance frequencies are in good agreement with the theoretical results. This kind of sandwich piezoelectric ultrasonic transducer is expected to be used in megasonic ultrasonic cleaning and sonochemistry where high power and high frequency ultrasound is needed

Dielectric and piezoelectric characteristics of lead-free Bi{sub 0.5}(Na{sub 0.84}K{sub 0.16}){sub 0.5}TiO{sub 3} ceramics substituted with Sr

Energy Technology Data Exchange (ETDEWEB)

Yoo, Juhyun [Department of Electrical Engineering, Semyung University Jechon, Chungbuk, 390-711 (Korea, Republic of); Oh, Dongon [Sunny Electronics Corporation, Chungju, 380-240 (Korea, Republic of); Jeong, Yeongho [Korea Electric Power Research Institute, Yusung-Gu, Taejon 305-380 (Korea, Republic of); Hong, Jaeil [Department of Electricity, Dongseoul Tech. Jr. College, 255 Soo Jung-Ku, Sung Nam (Korea, Republic of); Jung, Moonyoung [Department of Earth Resources and Environmental Geotechnics Engineering, Semyung University Jechon, Chungbuk, 390-711 (Korea, Republic of)

2004-11-01

In this study, lead-free Bi{sub 0.5}(Na{sub 0.84}K{sub 0.16}){sub 0.5}TiO{sub 3} ceramics were fabricated with the variations of Sr substitution and their dielectric and piezoelectric characteristics were investigated. Through the analysis of XRD diffraction pattern and SEM, crystal structure and microstructure were evaluated. With the increasing amount of Sr substitution, dielectric constant linearly increased at the rate of about 90 per 1 mol% and Curie temperature decreased slightly. Also, the temperature dependence curve of dielectric constant moved leftward. At 4 mol% Sr substitution, T{sub c} of 292C, k{sub p} of 34.3%, k{sub t} of 45.32%, and d{sub 33} of 185 pC/N were obtained, respectively.

Piezoelectric Active Humidity Sensors Based on Lead-Free NaNbO3 Piezoelectric Nanofibers

Directory of Open Access Journals (Sweden)

Li Gu

2016-06-01

Full Text Available The development of micro-/nano-scaled energy harvesters and the self-powered sensor system has attracted great attention due to the miniaturization and integration of the micro-device. In this work, lead-free NaNbO3 piezoelectric nanofibers with a monoclinic perovskite structure were synthesized by the far-field electrospinning method. The flexible active humidity sensors were fabricated by transferring the nanofibers from silicon to a soft polymer substrate. The sensors exhibited outstanding piezoelectric energy-harvesting performance with output voltage up to 2 V during the vibration process. The output voltage generated by the NaNbO3 sensors exhibited a negative correlation with the environmental humidity varying from 5% to 80%, where the peak-to-peak value of the output voltage generated by the sensors decreased from 0.40 to 0.07 V. The sensor also exhibited a short response time, good selectively against ethanol steam, and great temperature stability. The piezoelectric active humidity sensing property could be attributed to the increased leakage current in the NaNbO3 nanofibers, which was generated due to proton hopping among the H3O+ groups in the absorbed H2O layers under the driving force of the piezoelectric potential.

Investigation of the structure and properties of (KxNa1-x)NbO3-based piezoelectric ceramics using both conventional and high-throughput experimentation (HTE) methods

International Nuclear Information System (INIS)

Mgbemere, Henry Ekene

2012-01-01

The structure and properties of (K x Na 1-x )NbO 3 lead-free piezoelectric ceramics was investigated in this work. Both the conventional mixed-oxide ceramics synthesis route and the high-throughput experimentation (HTE) approaches were employed for the synthesis. Structural characterization was carried out with synchrotron X-rays while the electrical properties were characterized with techniques (dielectric measurement, hysteresis measurements, impedance measurements etc). Both isovalent and aliovalent elements (Ta, Sb, Li) were used to dope (K x Na 1-x )NbO 3 ceramics in order to improve its piezoelectric properties and sinterability.

Growth and characterization of lead-free (K,Na)NbO{sub 3}-based piezoelectric single crystals

Energy Technology Data Exchange (ETDEWEB)

Liu, Hairui

2016-10-19

Lead-free piezoelectric materials have received increasing attention in the last decade, driven by environmental issues and health concerns. Of considerable interest is the (K,Na)NbO{sub 3} (KNN)-based system, which possesses a relatively high Curie temperature and good piezoelectric properties. Abundant publications on KNN-based polycrystalline ceramics increased the interest in studying their single-crystalline form, based on two major concerns. The first concern refers to the negative role of grain interactions on the electromechanical response. The second concern deals with domain engineering. The relationship between external electric field direction, crystallographic orientation, and spontaneous polarization vectors for a specific structure can be more readily established in single crystals and thus offers a pathway for an in-depth understanding of fundamental mechanism and potential applications. The exciting enhancement of both piezoelectric and ferroelectric response in lead-based single crystals also encourages the further exploration of KNN-based piezoelectric crystals, as they possess the same perovskite structure. The main goal of this thesis is to find possible approaches for improved electromechanical properties in KNN-based piezoelectric single crystals. In Chapter 2, the current development of KNN-based single crystals as piezoelectrics is reviewed, following a short introduction of fundamental knowledge on piezoelectrics and ferroelectrics. Both submerged-seed solution growth and top-seeded solution growth techniques were employed to produce single crystals, as described detailed in Chapter 3. Emphasis is subsequently placed on issues of the crystal growth process, effective methods to enhance electrical properties, and crystallographic orientation-dependent electrical properties in Li-, Ta-, and/or Sb-substituted KNN single crystals. The main conclusions from the crystal growth aspect are presented in Chapter 4 and can be summarized as follows

The effects of sintering behavior on piezoelectric properties of porous PZT ceramics for hydrophone application

International Nuclear Information System (INIS)

Zeng Tao; Dong Xianlin; Chen Heng; Wang Yonglin

2006-01-01

Porous lead zirconate titanate (PZT) ceramics were fabricated by adding polymethyl methacrylate (PMMA) and the effects of sintering behavior on their microstructure and piezoelectric properties were investigated. The porosity of PZT ceramics decreased with an increase in the sintering temperature at a fixed PMMA addition. The dielectric constant (ε), longitudinal piezoelectric coefficient (d 33 ) and hydrostatic figures of merit (d h g h ) of 34% porous PZT ceramics increased with an increase in sintering temperature from 1050 to 1300 deg. C. When sintered at 1300 deg. C, longitudinal piezoelectric coefficient of 34% porous PZT ceramic was very close to that of 95% dense PZT ceramics, while the hydrostatic figures of merit of 34% porous PZT ceramics is about fifteen times more than that of 95% dense PZT ceramics. Compared with PZT-polymer composites, the dielectric constant of 34% porous PZT sintered at 1300 deg. C is much higher, which can be more efficient to resist the interference in receiving sensitivities caused by loading effect of the cable

Giant strain with low cycling degradation in Ta-doped [Bi{sub 1/2}(Na{sub 0.8}K{sub 0.2}){sub 1/2}]TiO{sub 3} lead-free ceramics

Energy Technology Data Exchange (ETDEWEB)

Liu, Xiaoming; Tan, Xiaoli, E-mail: xtan@iastate.edu [Department of Materials Science and Engineering, Iowa State University, Ames, Iowa 50011 (United States)

2016-07-21

Non-textured polycrystalline [Bi{sub 1/2}(Na{sub 0.8}K{sub 0.2}){sub 1/2}](Ti{sub 1−x}Ta{sub x})O{sub 3} ceramics are fabricated and their microstructures and electrical properties are characterized. Transmission electron microscopy reveals the coexistence of the rhombohedral R3c and tetragonal P4bm phases in the form of nanometer-sized domains in [Bi{sub 1/2}(Na{sub 0.8}K{sub 0.2}){sub 1/2}]TiO{sub 3} with low Ta concentration. When the composition is x = 0.015, the electrostrain is found to be highly asymmetric under bipolar fields of ±50 kV/cm. A very large value of 0.62% is observed in this ceramic, corresponding to a large-signal piezoelectric coefficient d{sub 33}* of 1240 pm/V (1120 pm/V under unipolar loading). These values are greater than most previously reported lead-free polycrystalline ceramics and can even be compared with some lead-free piezoelectric single crystals. Additionally, this ceramic displays low cycling degradation; its electrostrain remains above 0.55% even after undergoing 10 000 cycles of ±50 kV/cm bipolar fields at 2 Hz. Therefore, Ta-doped [Bi{sub 1/2}(Na{sub 0.8}K{sub 0.2}){sub 1/2}]TiO{sub 3} ceramics show great potential for large displacement devices.

Bismuth Sodium Titanate Based Materials for Piezoelectric Actuators.

Science.gov (United States)

Reichmann, Klaus; Feteira, Antonio; Li, Ming

2015-12-04

The ban of lead in many electronic products and the expectation that, sooner or later, this ban will include the currently exempt piezoelectric ceramics based on Lead-Zirconate-Titanate has motivated many research groups to look for lead-free substitutes. After a short overview on different classes of lead-free piezoelectric ceramics with large strain, this review will focus on Bismuth-Sodium-Titanate and its solid solutions. These compounds exhibit extraordinarily high strain, due to a field induced phase transition, which makes them attractive for actuator applications. The structural features of these materials and the origin of the field-induced strain will be revised. Technologies for texturing, which increases the useable strain, will be introduced. Finally, the features that are relevant for the application of these materials in a multilayer design will be summarized.

Correlation between the structure and the piezoelectric properties of lead-free (K,Na,Li)(Nb,Ta,Sb)O3 ceramics studied by XRD and Raman spectroscopy.

Science.gov (United States)

Rubio-Marcos, Fernando; Marchet, Pascal; Romero, Juan José; Fernández, Jose F

2011-09-01

This article reviews on the use of Raman spectroscopy for the study of (K,Na,Li)(Nb,Ta,Sb)O(3) lead-free piezoceramics. Currently, this material appears to be one of the most interesting and promising alternatives to the well-known PZT piezoelectric materials. In this work, we prepare piezoceramics with different stoichiometries and study their structural, ferroelectric, and piezoelectric properties. By using both Raman spectroscopy and X-ray diffraction, we establish a direct correlation between the structure and the properties. The results demonstrate that the wavenumber of the A(1g) vibration is proportional to the tetragonality, the remnant polarization, and the piezoelectric coefficients of these materials. Thus, Raman spectroscopy appears as a very useful technique for a fast evaluation of the crystalline structure and the ferroelectric/ piezoelectric properties.

Development of optical phase shifter based on piezoelectric ceramic

Science.gov (United States)

Yu, Fusheng; Shen, Xiaoqin; Yao, Chunjuan; Leng, Changlin

2005-02-01

The phase shifter is necessary in the optical phase-shifting measurement. At present the phase shifter commonly used is approximately divided into the penetrance-type and the reflection-type. In this paper, a reflection-type phase shifter made of piezoelectric ceramic stackup assemble is developed. The assemble are constituted of the flat piezoelectric ceramic with parallel connection circuit and inline structure. The communication between the computer and MCU is by RS232. The D/A converter controlled by the MCU outputs 0~10V voltage. Then the voltage is amplified to 0~400V DC voltage by the designed linear DC amplifier. When this voltage loads on the piezoelectric ceramic stackup assemble, the assemble will axially extend 0~5mm. In this paper, the connecting types for the mechanical construction and circuit of the piezoelectric ceramic stackup assemble, the driving power and the DC amplifier with high linearity are all introduced. The whole system developed is standardized by using phase-interfering Michelson. The standardization and the practical application indicates that this system has excellent linearity and precision repeatability.

Strong and anisotropic magnetoelectricity in composites of magnetostrictive Ni and solid-state grown lead-free piezoelectric BZT–BCT single crystals

Directory of Open Access Journals (Sweden)

Haribabu Palneedi

2017-03-01

Full Text Available Aimed at developing lead-free magnetoelectric (ME composites with performances as good as lead (Pb-based ones, this study employed (001 and (011 oriented 82BaTiO3-10BaZrO3-8CaTiO3 (BZT–BCT piezoelectric single crystals, fabricated by the cost-effective solid-state single crystal growth (SSCG method, in combination with inexpensive, magnetostrictive base metal Nickel (Ni. The off-resonance, direct ME coupling in the prepared Ni/BZT–BCT/Ni laminate composites was found to be strongly dependent on the crystallographic orientation of the BZT–BCT single crystals, as well as the applied magnetic field direction. Larger and anisotropic ME voltage coefficients were observed for the composite made using the (011 oriented BZT–BCT single crystal. The optimized ME coupling of 1 V/cm Oe was obtained from the Ni/(011 BZT–BCT single crystal/Ni composite, in the d32 mode of the single crystal, when a magnetic field was applied along its [100] direction. This performance is similar to that reported for the Ni/Pb(Mg1/3Nb2/3O3-Pb(Zr,TiO3 (PMN–PZT single crystal/Ni, but larger than that obtained from the Ni/Pb(Zr,TiO3 ceramic/Ni composites. The results of this work demonstrate that the use of lead-free piezoelectric single crystals with special orientations permits the selection of desired anisotropic properties, enabling the realization of customized ME effects in composites.

Microstructure, Piezoelectric, and Ferroelectric Properties of BZT-Modified BiFeO3-BaTiO3 Multiferroic Ceramics with MnO2 and CuO Addition

Science.gov (United States)

Guan, Shibo; Yang, Huabin; Chen, Guangcong; Zhang, Rui

2018-02-01

A new lead-free piezoelectric ceramic, 0.67BiFeO3-0.33BaTiO3-xBi(Zn0.5Ti0.5) O3 + 0.0035MnO2 + 0.004CuO, was prepared through the solid-state reaction route. The ceramic was sintered in the 950-990°C range. In this paper, the crystal structure of the sample is pure perovskite structure with a pseudo-cubic structure in the range of x = 0-0.05, and does not change greatly with the increase of x. The grain size increases first and then decreases with the increase of x. The addition of Bi(Zn0.5Ti0.5) O3(BZT) promoted the grain growth of the sample. The piezoelectric constant reached the maximum value of d 33 = 188 pC/N, electromechanical coupling coefficient k p = 0.301 and the remanent polarization P r = 61.20 μC/cm2 at x = 0.03. It has a high Curie temperature of T c = 420°C. On the other hand, the depolarization temperature reaches the maximum value, T d = 426°C, at x = 0. A small amount of BZT doping can improve the piezoelectric, dielectric, and ferroelectric properties of the samples. Therefore, this material can be considered as a promising lead-free piezoelectric ceramic material in the application field of high-temperature materials.

Lead-free piezoelectric transducers for vibration-based energy harvesting devices

Energy Technology Data Exchange (ETDEWEB)

Roescher, Mark

2011-11-15

Future applications like piezoelectric energy harvesters in addition with increasing environmental awareness ultimately demand novel sophisticated material systems in the field of piezoelectrics as an alternative to the long-established system lead-zirconate-titanate. In this publication state-of-the-art microgenerators have been designed to possess nonlinear Duffing oscillator characteristics. It is shown by measurement and simulation that lead-zirconate-titanate may hence no longer be the first choice in material selection for a piezoelectric microgenerator. Polyvinylidene fluoride has been integrated in a piezoelectric microgenerator and identified as an extraordinarily promising material system for transducer applications being highly insusceptible to stretching induced material failure. Finally, a fundamentally new chemical synthesis approach has been developed for the fabrication of potassium-sodium-niobate films that may also be suitable for other complex oxides.

Giant strain with ultra-low hysteresis and high temperature stability in grain oriented lead-free K0.5Bi0.5TiO3-BaTiO3-Na0.5Bi0.5TiO3 piezoelectric materials.

Science.gov (United States)

Maurya, Deepam; Zhou, Yuan; Wang, Yaojin; Yan, Yongke; Li, Jiefang; Viehland, Dwight; Priya, Shashank

2015-02-26

We synthesized grain-oriented lead-free piezoelectric materials in (K0.5Bi0.5TiO3-BaTiO3-xNa0.5Bi0.5TiO3 (KBT-BT-NBT) system with high degree of texturing along the [001]c (c-cubic) crystallographic orientation. We demonstrate giant field induced strain (~0.48%) with an ultra-low hysteresis along with enhanced piezoelectric response (d33 ~ 190pC/N) and high temperature stability (~160°C). Transmission electron microscopy (TEM) and piezoresponse force microscopy (PFM) results demonstrate smaller size highly ordered domain structure in grain-oriented specimen relative to the conventional polycrystalline ceramics. The grain oriented specimens exhibited a high degree of non-180° domain switching, in comparison to the randomly axed ones. These results indicate the effective solution to the lead-free piezoelectric materials.

Large Electrocaloric Effect in Lead-Free (Ba0.85Ca0.15)(Zr0.1Ti0.9)O3 Ceramics Prepared via Citrate Route

Science.gov (United States)

Shi, Jing; Zhu, Rongfeng; Liu, Xing; Yuan, Ningyi; Ding, Jianning; Luo, Haosu

2017-01-01

The 1 wt % Li-doped (Ba0.85Ca0.15)(Zr0.1Ti0.9)O3 (BCZT-Li) ceramics prepared by the citrate method exhibit improved phase purity, densification and electrical properties, which provide prospective possibility to develop high-performance electrocaloric materials. The electrocaloric effect was evaluated by phenomenological method, and the BCZT-Li ceramics present large electrocaloric temperature change ∆T, especially large electrocaloric responsibility ξ = ∆Tmax/∆Emax, which can be comparable to the largest values reported in the lead-free piezoelectric ceramics. The excellent electrocaloric effect is considered as correlating with the coexistence of polymorphic ferroelectric phases, which are detected by the Raman spectroscopy. The large ξ value accompanied by decreased Curie temperature (around 73 °C) of the BCZT-Li ceramics prepared by the citrate method presents potential applications as the next-generation solid-state cooling devices. PMID:28927004

Large Electrocaloric Effect in Lead-Free (Ba0.85Ca0.15(Zr0.1Ti0.9O3 Ceramics Prepared via Citrate Route

Directory of Open Access Journals (Sweden)

Jing Shi

2017-09-01

Full Text Available The 1 wt % Li-doped (Ba0.85Ca0.15(Zr0.1Ti0.9O3 (BCZT-Li ceramics prepared by the citrate method exhibit improved phase purity, densification and electrical properties, which provide prospective possibility to develop high-performance electrocaloric materials. The electrocaloric effect was evaluated by phenomenological method, and the BCZT-Li ceramics present large electrocaloric temperature change ∆T, especially large electrocaloric responsibility ξ = ∆Tmax/∆Emax, which can be comparable to the largest values reported in the lead-free piezoelectric ceramics. The excellent electrocaloric effect is considered as correlating with the coexistence of polymorphic ferroelectric phases, which are detected by the Raman spectroscopy. The large ξ value accompanied by decreased Curie temperature (around 73 °C of the BCZT-Li ceramics prepared by the citrate method presents potential applications as the next-generation solid-state cooling devices.

High Performance Lead--free Piezoelectric Materials

OpenAIRE

Gupta, Shashaank

2013-01-01

Piezoelectric materials find applications in number of devices requiring inter-conversion of mechanical and electrical energy.  These devices include different types of sensors, actuators and energy harvesting devices. A number of lead-based perovskite compositions (PZT, PMN-PT, PZN-PT etc.) have dominated the field in last few decades owing to their giant piezoresponse and convenient application relevant tunability. With increasing environmental concerns, in the last one decade, focus has be...

Lead-free LiNbO3 nanowire-based nanocomposite for piezoelectric power generation

Science.gov (United States)

2014-01-01

In a flexible nanocomposite-based nanogenerator, in which piezoelectric nanostructures are mixed with polymers, important parameters to increase the output power include using long nanowires with high piezoelectricity and decreasing the dielectric constant of the nanocomposite. Here, we report on piezoelectric power generation from a lead-free LiNbO3 nanowire-based nanocomposite. Through ion exchange of ultra-long Na2Nb2O6-H2O nanowires, we synthesized long (approximately 50 μm in length) single-crystalline LiNbO3 nanowires having a high piezoelectric coefficient (d33 approximately 25 pmV-1). By blending LiNbO3 nanowires with poly(dimethylsiloxane) (PDMS) polymer (volume ratio 1:100), we fabricated a flexible nanocomposite nanogenerator having a low dielectric constant (approximately 2.7). The nanogenerator generated stable electric power, even under excessive strain conditions (approximately 105 cycles). The different piezoelectric coefficients of d33 and d31 for LiNbO3 may have resulted in generated voltage and current for the e33 geometry that were 20 and 100 times larger than those for the e31 geometry, respectively. This study suggests the importance of the blending ratio and strain geometry for higher output-power generation in a piezoelectric nanocomposite-based nanogenerator. PACS 77.65.-j; 77.84.-s; 73.21.Hb PMID:24386884

Flexible Piezoelectric Touch Sensor by Alignment of Lead-Free Alkaline Niobate Microcubes in PDMS

NARCIS (Netherlands)

Deutz, D.B.; Mascarenhas, N.T.; Schelen, J.B.J.; de Leeuw, D.M.; van der Zwaag, S.; Groen, W.A.

2017-01-01

A highly sensitive, lead-free, and flexible piezoelectric touch sensor is reported based on composite films of alkaline niobate K_0.485Na_0.485Li_0.03NbO₃ (KNLN) powders aligned in a polydimethylsiloxane (PDMS) matrix. KNLN powder is fabricated by

Role of sintering time, crystalline phases and symmetry in the piezoelectric properties of lead-free KNN-modified ceramics

International Nuclear Information System (INIS)

Rubio-Marcos, F.; Marchet, P.; Merle-Mejean, T.; Fernandez, J.F.

2010-01-01

Lead-free KNN-modified piezoceramics of the system (Li,Na,K)(Nb,Ta,Sb)O 3 were prepared by conventional solid-state sintering. The X-ray diffraction patterns revealed a perovskite phase, together with some minor secondary phase, which was assigned to K 3 LiNb 6 O 17 , tetragonal tungsten-bronze (TTB). A structural evolution toward a pure tetragonal structure with the increasing sintering time was observed, associated with the decrease of TTB phase. A correlation between higher tetragonality and higher piezoelectric response was clearly evidenced. Contrary to the case of the LiTaO 3 modified KNN, very large abnormal grains with TTB structure were not detected. As a consequence, the simultaneous modification by tantalum and antimony seems to induce during sintering a different behaviour from the one of LiTaO 3 modified KNN.

Role of sintering time, crystalline phases and symmetry in the piezoelectric properties of lead-free KNN-modified ceramics

Energy Technology Data Exchange (ETDEWEB)

Rubio-Marcos, F., E-mail: frmarcos@icv.csic.es [Electroceramic Department, Instituto de Ceramica y Vidrio, CSIC, Kelsen 5, 28049 Madrid (Spain); Marchet, P.; Merle-Mejean, T. [SPCTS, UMR 6638 CNRS, Universite de Limoges, 123, Av. A. Thomas, 87060 Limoges (France); Fernandez, J.F. [Electroceramic Department, Instituto de Ceramica y Vidrio, CSIC, Kelsen 5, 28049 Madrid (Spain)

2010-09-01

Lead-free KNN-modified piezoceramics of the system (Li,Na,K)(Nb,Ta,Sb)O{sub 3} were prepared by conventional solid-state sintering. The X-ray diffraction patterns revealed a perovskite phase, together with some minor secondary phase, which was assigned to K{sub 3}LiNb{sub 6}O{sub 17}, tetragonal tungsten-bronze (TTB). A structural evolution toward a pure tetragonal structure with the increasing sintering time was observed, associated with the decrease of TTB phase. A correlation between higher tetragonality and higher piezoelectric response was clearly evidenced. Contrary to the case of the LiTaO{sub 3} modified KNN, very large abnormal grains with TTB structure were not detected. As a consequence, the simultaneous modification by tantalum and antimony seems to induce during sintering a different behaviour from the one of LiTaO{sub 3} modified KNN.

Porosity Dependence of Piezoelectric Properties for Porous Potassium Niobate System Ceramics

Energy Technology Data Exchange (ETDEWEB)

Wada, S; Mase, Y; Shimizu, S; Maeda, K; Fujii, I; Nakashima, K; Pulpan, P; Miyajima, N, E-mail: swada@yamanashi.ac.jp [Interdisciplinary Graduate School of Medical and Engineering, University of Yamanashi, 4-4-37 Takeda, Kofu, Yamanashi 400-8510 (Japan)

2011-10-29

Porous potassium niobate (KNbO{sub 3}, KN) system ceramics were prepared by a conventional sintering method using carbon black (CB) nanoparticles. First, KN nanoparticles with a size of 100 nm was mixed with CB nanoparticles and binder using ball milling with ethanol. The mixture was dried, and pressed into pellets using uniaxial pressing. After binder burnout, these ceramics was sintered in air. Their piezoelectric properties were measured and discussed a relationship between porosity and piezoelectric properties. As the results, with increasing porosity, piezoelectric g33 constant increased significantly, which suggested that porous ceramics were effective for stress sensor application.

Porosity Dependence of Piezoelectric Properties for Porous Potassium Niobate System Ceramics

International Nuclear Information System (INIS)

Wada, S; Mase, Y; Shimizu, S; Maeda, K; Fujii, I; Nakashima, K; Pulpan, P; Miyajima, N

2011-01-01

Porous potassium niobate (KNbO 3 , KN) system ceramics were prepared by a conventional sintering method using carbon black (CB) nanoparticles. First, KN nanoparticles with a size of 100 nm was mixed with CB nanoparticles and binder using ball milling with ethanol. The mixture was dried, and pressed into pellets using uniaxial pressing. After binder burnout, these ceramics was sintered in air. Their piezoelectric properties were measured and discussed a relationship between porosity and piezoelectric properties. As the results, with increasing porosity, piezoelectric g33 constant increased significantly, which suggested that porous ceramics were effective for stress sensor application.

Lead-free piezoelectric KNN-BZ-BNT films with a vertical morphotropic phase boundary

Directory of Open Access Journals (Sweden)

Wen Chen

2015-07-01

Full Text Available The lead-free piezoelectric 0.915K0.5Na0.5NbO3-0.075BaZrO3-0.01Bi0.5Na0.5TiO3 (0.915KNN-0.075BZ-0.01BNT films were prepared by a chemical solution deposition method. The films possess a pure rhomobohedral perovskite phase and a dense surface without crack. The temperature-dependent dielectric properties of the specimens manifest that only phase transition from ferroelectric to paraelectric phase occurred and the Curie temperature is 217 oC. The temperature stability of ferroelectric phase was also supported by the stable piezoelectric properties of the films. These results suggest that the slope of the morphotropic phase boundary (MPB for the solid solution formed with the KNN and BZ in the films should be vertical. The voltage-induced polarization switching, and a distinct piezo-response suggested that the 0.915 KNN-0.075BZ-0.01BNT films show good piezoelectric properties.

Contribution of the irreversible displacement of domain walls to the piezoelectric effect in barium titanate and lead zirconate titanate ceramics

CERN Document Server

Damjanovic, D

1997-01-01

The contribution from the irreversible displacement of non-180 deg domain walls to the direct longitudinal piezoelectric d sub 3 sub 3 coefficient of BaTiO sub 3 and Pb(Zr, Ti)O sub 3 ceramics was determined quantitatively by using the Rayleigh law. Effects of the crystal structure and microstructure of the ceramics as well as the external d.c. pressure on the domain wall contribution to d sub 3 sub 3 were examined. In barium titanate, this domain wall contribution is large (up to 35% of the total d sub 3 sub 3 , under the experimental conditions used) and dependent on the external d.c. pressure in coarse grained ceramics, and much smaller and independent of the external d.c. pressure in fine-grained samples. The presence of internal stresses in fine-grained ceramics could account for the observed behaviour. The analysis shows that the domain-wall contribution to the d sub 3 sub 3 in lead zirconate titanate ceramics is large in compositions close to the morphotropic phase boundary that contain a mixture of te...

Compositional Design of Dielectric, Ferroelectric and Piezoelectric Properties of (K, Na)NbO₃ and (Ba, Na)(Ti, Nb)O₃ Based Ceramics Prepared by Different Sintering Routes.

Science.gov (United States)

Eiras, José A; Gerbasi, Rosimeire B Z; Rosso, Jaciele M; Silva, Daniel M; Cótica, Luiz F; Santos, Ivair A; Souza, Camila A; Lente, Manuel H

2016-03-08

Lead free piezoelectric materials are being intensively investigated in order to substitute lead based ones, commonly used in many different applications. Among the most promising lead-free materials are those with modified NaNbO₃, such as (K, Na)NbO₃ (KNN) and (Ba, Na)(Ti, Nb)O₃ (BTNN) families. From a ceramic processing point of view, high density single phase KNN and BTNN ceramics are very difficult to sinter due to the volatility of the alkaline elements, the narrow sintering temperature range and the anomalous grain growth. In this work, Spark Plasma Sintering (SPS) and high-energy ball milling (HEBM), following heat treatments (calcining and sintering), in oxidative (O₂) atmosphere have been used to prepare single phase highly densified KNN ("pure" and Cu 2+ or Li 1+ doped), with theoretical densities ρ th > 97% and BTNN ceramics (ρ th - 90%), respectively. Using BTTN ceramics with a P 4 mm perovskite-like structure, we showed that by increasing the NaNbO₃ content, the ferroelectric properties change from having a relaxor effect to an almost "normal" ferroelectric character, while the tetragonality and grain size increase and the shear piezoelectric coefficients ( k 15 , g 15 and d 15 ) improve. For KNN ceramics, the results reveal that the values for remanent polarization as well as for most of the coercive field are quite similar among all compositions. These facts evidenced that Cu 2+ may be incorporated into the A and/or B sites of the perovskite structure, having both hardening and softening effects.

Dielectric and piezoelectric properties of lead-free (Bi,Na)TiO3-based thin films

Science.gov (United States)

Abazari, M.; Safari, A.; Bharadwaja, S. S. N.; Trolier-McKinstry, S.

2010-02-01

Dielectric and piezoelectric properties of morphotropic phase boundary (Bi,Na)TiO3-(Bi,K)TiO3-BaTiO3 epitaxial thin films deposited on SrRuO3 coated SrTiO3 substrates were reported. Thin films of 350 nm thickness exhibited small signal dielectric permittivity and loss tangent values of 750 and 0.15, respectively, at 1 kHz. Ferroelectric hysteresis measurements indicated a remanent polarization value of 30 μC/cm2 with a coercive field of 85-100 kV/cm. The thin film transverse piezoelectric coefficient (e31,f) of these films after poling at 600 kV/cm was found to be -2.2 C/m2. The results indicate that these BNT-based thin films are a potential candidate for lead-free piezoelectric devices.

Correlation of Bulk Dielectric and Piezoelectric Properties to the Local Scale Phase Transformations, Domain Morphology, and Crystal Structure Modified

Energy Technology Data Exchange (ETDEWEB)

Priya, Shashank [Virginia Polytechnic Inst. and State Univ. (Virginia Tech), Blacksburg, VA (United States); Viehland, Dwight [Virginia Polytechnic Inst. and State Univ. (Virginia Tech), Blacksburg, VA (United States)

2014-12-14

Three year program entitled “Correlation of bulk dielectric and piezoelectric properties to the local scale phase transformations, domain morphology, and crystal structure in modified lead-free grain-textured ceramics and single crystals” was supported by the Department of Energy. This was a joint research program between D. Viehland and S. Priya at Virginia Tech. Single crystal and textured ceramics have been synthesized and characterized. Our goals have been (i) to conduct investigations of lead-free piezoelectric systems to establish the local structural and domain morphologies that result in enhanced properties, and (ii) to synthesize polycrystalline and grain oriented ceramics for understanding the role of composition, microstructure, and anisotropy

Piezoelectric ceramic implants: in vivo results.

Science.gov (United States)

Park, J B; Kelly, B J; Kenner, G H; von Recum, A F; Grether, M F; Coffeen, W W

1981-01-01

The suitability of barium titanate (BaTiO3) ceramic for direct substitution of hard tissues was evaluated using both electrically stimulated (piezoelectric) and inactive (nonpolarized) test implants. Textured cylindrical specimens, half of them made piezoelectric by polarization in a high electric field, were implanted into the cortex of the midshaft region of the femora of dogs for various periods of time. Interfacial healing and bio-compatibility of the implant material were studied using mechanical, microradiographical, and histological techniques. Our results indicate that barium titanate ceramic shows a very high degree of biocompatibility as evidenced by the absence of inflammatory or foreign body reactions at the implant-tissue interface. Furthermore, the material and its surface porosity allowed a high degree of bone ingrowth as evidenced by microradiography and a high degree of interfacial tensile strength. No difference was found between the piezoelectric and the electrically neutral implant-tissue interfaces. Possible reasons for this are discussed. The excellent mechanical properties of barium titanate, its superior biocompatibility, and the ability of bone to form a strong mechanical interfacial bond with it, makes this material a new candidate for further tests for hard tissue replacement.

Microstructure Control of Barium Titanate Grain-oriented Ceramics and Their Piezoelectric Properties

International Nuclear Information System (INIS)

Mori, Rintaro; Nakashima, Koichi; Fujii, Ichiro; Wada, Satoshi; Hayashi, Hiroshi; Nagamori, Yoshitaka; Yamamoto, Yuichi

2011-01-01

The Barium titanate (BaTiO 3 , BT) [110] grain-oriented ceramics along [110] direction were prepared by a templated grain growth (TGG) method. The [110] oriented BT platelike particles (t-BT) were used as template particles. The relationship between poling treatment program and piezoelectric constant was investigated. The change in the poling conditions did not greatly influence domain size and the piezoelectric constant. The relationship between piezoelectric properties and domain size in BT grain-oriented ceramics was investigated. The smaller domain size was required to increase the piezoelectric constant.

Nanoscale characterization and local piezoelectric properties of lead-free KNN-LT-LS thin films

Energy Technology Data Exchange (ETDEWEB)

Abazari, M; Safari, A [Glenn Howatt Electroceramics Laboratories, Department of Materials Science and Engineering, Rutgers-The state University of New Jersey, Piscataway, NJ 08854 (United States); Choi, T; Cheong, S-W [Rutgers Center for Emergent Materials, Department of Physics and Astronomy, Rutgers-The state University of New Jersey, Piscataway, NJ 08854 (United States)

2010-01-20

We report the observation of domain structure and piezoelectric properties of pure and Mn-doped (K{sub 0.44},Na{sub 0.52},Li{sub 0.04})(Nb{sub 0.84},Ta{sub 0.1},Sb{sub 0.06})O{sub 3} (KNN-LT-LS) thin films on SrTiO{sub 3} substrates. It is revealed that, using piezoresponse force microscopy, ferroelectric domain structure in such 500 nm thin films comprised of primarily 180{sup 0} domains. This was in accordance with the tetragonal structure of the films, confirmed by relative permittivity measurements and x-ray diffraction patterns. Effective piezoelectric coefficient (d{sub 33}) of the films were calculated using piezoelectric displacement curves and shown to be {approx}53 pm V{sup -1} for pure KNN-LT-LS thin films. This value is among the highest values reported for an epitaxial lead-free thin film and shows a great potential for KNN-LT-LS to serve as an alternative to PZT thin films in future applications.

Nanoscale characterization and local piezoelectric properties of lead-free KNN-LT-LS thin films

Science.gov (United States)

Abazari, M.; Choi, T.; Cheong, S.-W.; Safari, A.

2010-01-01

We report the observation of domain structure and piezoelectric properties of pure and Mn-doped (K0.44,Na0.52,Li0.04)(Nb0.84,Ta0.1,Sb0.06)O3 (KNN-LT-LS) thin films on SrTiO3 substrates. It is revealed that, using piezoresponse force microscopy, ferroelectric domain structure in such 500 nm thin films comprised of primarily 180° domains. This was in accordance with the tetragonal structure of the films, confirmed by relative permittivity measurements and x-ray diffraction patterns. Effective piezoelectric coefficient (d33) of the films were calculated using piezoelectric displacement curves and shown to be ~53 pm V-1 for pure KNN-LT-LS thin films. This value is among the highest values reported for an epitaxial lead-free thin film and shows a great potential for KNN-LT-LS to serve as an alternative to PZT thin films in future applications.

Silver Niobate Lead-Free Antiferroelectric Ceramics: Enhancing Energy Storage Density by B-Site Doping.

Science.gov (United States)

Zhao, Lei; Gao, Jing; Liu, Qing; Zhang, Shujun; Li, Jing-Feng

2018-01-10

Lead-free dielectric ceramics with high recoverable energy density are highly desired to sustainably meet the future energy demand. AgNbO 3 -based lead-free antiferroelectric ceramics with double ferroelectric hysteresis loops have been proved to be potential candidates for energy storage applications. Enhanced energy storage performance with recoverable energy density of 3.3 J/cm 3 and high thermal stability with minimal energy density variation (<10%) over a temperature range of 20-120 °C have been achieved in W-modified AgNbO 3 ceramics. It is revealed that the W 6+ cations substitute the B-site Nb 5+ and reduce the polarizability of B-site cations, leading to the enhanced antiferroelectricity, which is confirmed by the polarization hysteresis and dielectric tunability. It is believed that the polarizability of B-site cations plays a dominant role in stabilizing the antiferroelectricity in AgNbO 3 system, in addition to the tolerance factor, which opens up a new design approach to achieve stable antiferroelectric materials.

Exceptionally High Piezoelectric Coefficient and Low Strain Hysteresis in Grain-Oriented (Ba, Ca)(Ti, Zr)O3 through Integrating Crystallographic Texture and Domain Engineering.

Science.gov (United States)

Liu, Yingchun; Chang, Yunfei; Li, Fei; Yang, Bin; Sun, Yuan; Wu, Jie; Zhang, Shantao; Wang, Ruixue; Cao, Wenwu

2017-09-06

Both low strain hysteresis and high piezoelectric performance are required for practical applications in precisely controlled piezoelectric devices and systems. Unfortunately, enhanced piezoelectric properties were usually obtained with the presence of a large strain hysteresis in BaTiO 3 (BT)-based piezoceramics. In this work, we propose to integrate crystallographic texturing and domain engineering strategies into BT-based ceramics to resolve this challenge. [001] c grain-oriented (Ba 0.94 Ca 0.06 )(Ti 0.95 Zr 0.05 )O 3 (BCTZ) ceramics with a texture degree as high as 98.6% were synthesized by templated grain growth. A very high piezoelectric coefficient (d 33 ) of 755 pC/N, and an extremely large piezoelectric strain coefficient (d 33 * = 2027 pm/V) along with an ultralow strain hysteresis (H s ) of 4.1% were simultaneously achieved in BT-based systems for the first time, which are among the best values ever reported on both lead-free and lead-based piezoceramics. The exceptionally high piezoelectric response is mainly from the reversible contribution, and can be ascribed to the piezoelectric anisotropy, the favorable domain configuration, and the formation of smaller sized domains in the BCTZ textured ceramics. This study paves a new pathway to develop lead-free piezoelectrics with both low strain hysteresis and high piezoelectric coefficient. More importantly, it represents a very exciting discovery with potential application of BT-based ceramics in high-precision piezoelectric actuators.

On the use of non-MPB lead zirconium titanate (PZT) granules for piezoelectric ceramic–polymer sensorial composites

NARCIS (Netherlands)

Shaji Karapuzha, A.; Kunnamkuzhakkal James, N.; van der Zwaag, S.; Groen, W.A.

2016-01-01

Modern flexible and sensitive sensors based on polymer–ceramic composites employ lead zirconate titanate (PZT) granulates having the morphotropic phase boundary (MPB) composition as the piezo active ingredient, as this composition gives the best properties in fully ceramic piezoelectric sensors.

On the use of non-MPB lead zirconium titanate (PZT) granules for piezoelectric ceramic–polymer sensorial composites

NARCIS (Netherlands)

Shaji Karapuzha, A.; Zwaag, S. van der; Groen, W.A.

2016-01-01

Modern flexible and sensitive sensors based on polymer–ceramic composites employ lead zirconate titanate (PZT) granulates having the morphotropic phase boundary (MPB) composition as the piezo active ingredient, as this composition gives the best properties in fully ceramic piezoelectric sensors. In

Recent developments in piezoelectric ceramic materials and deterioration of their properties

International Nuclear Information System (INIS)

Pasha, R.A.; Khan, M.Z.

2006-01-01

There has been growing interest in recent years in piezoelectric ceramic materials because of their excellent dielectric, sensing, actuating and efficient process control applications. Lead Zirconate Titanate (PZT), Barium Titanate (BaTi O/sub 3/) and Lead Metaniobate (PbNb/sub 2/ O/sub 6/) and PVDF Polymers and generally favored as smart sensing materials. These materials are being used in critical engineering systems and smart structure. Fatigue failure due to electrical and thermal shocking is a major issue in degradation of these materials. Lot of work has been done in this area but still various issues need to investigate. Recent developments and current issues in piezoelectric materials and deterioration of their properties in different working conditions are discussed. The development of Finite Element codes incorporating smart material element has provided an opportunity to solve some practical problems. The new piezoelectric finite element capability available in some commercial package like ANSYS makes it convenient to perform static dynamic and thermal analysis for the fully coupled piezoelectric and structural response. Researchers have a great scope to uncover the various properties of these smart materials in different environmental conditions. In present work an overall review of the title is presented. (author)

Enhanced ferroelectric and piezoelectric properties in La-modified PZT ceramics

Science.gov (United States)

Kour, P.; Pradhan, S. K.; Kumar, Pawan; Sinha, S. K.; Kar, Manoranjan

2016-06-01

The effect of lanthanum (La) doping on ferroelectric and piezoelectric properties of lead zirconate titanate (PZT) sample has been investigated. Pb1- x La x Zr0.52Ti0.48O3 ceramics with x = 0.00, 0.02, 0.04, 0.06 and 0.10 were prepared by the sol-gel technique. Raman and Fourier transforms infrared spectroscopy have been employed to understand the structural modification due to ionic size mismatch. Raman spectra show the existence of both rhombohedral and tetragonal crystal symmetries. It also shows the dielectric relaxation with increase in La concentration in the sample. The increase in lattice strain due to La doping increases the remnant polarization and coercive field. The linear piezoelectric coefficient increases with the increase in La concentration. It reveals that La-substituted PZT is a better candidate for piezoelectric sensor applications as compared to that of PZT.

Compositional Design of Dielectric, Ferroelectric and Piezoelectric Properties of (K, NaNbO3 and (Ba, Na(Ti, NbO3 Based Ceramics Prepared by Different Sintering Routes

Directory of Open Access Journals (Sweden)

José A. Eiras

2016-03-01

Full Text Available Lead free piezoelectric materials are being intensively investigated in order to substitute lead based ones, commonly used in many different applications. Among the most promising lead-free materials are those with modified NaNbO3, such as (K, NaNbO3 (KNN and (Ba, Na(Ti, NbO3 (BTNN families. From a ceramic processing point of view, high density single phase KNN and BTNN ceramics are very difficult to sinter due to the volatility of the alkaline elements, the narrow sintering temperature range and the anomalous grain growth. In this work, Spark Plasma Sintering (SPS and high-energy ball milling (HEBM, following heat treatments (calcining and sintering, in oxidative (O2 atmosphere have been used to prepare single phase highly densified KNN (“pure” and Cu2+ or Li1+ doped, with theoretical densities ρth > 97% and BTNN ceramics (ρth - 90%, respectively. Using BTTN ceramics with a P4mm perovskite-like structure, we showed that by increasing the NaNbO3 content, the ferroelectric properties change from having a relaxor effect to an almost “normal” ferroelectric character, while the tetragonality and grain size increase and the shear piezoelectric coefficients (k15, g15 and d15 improve. For KNN ceramics, the results reveal that the values for remanent polarization as well as for most of the coercive field are quite similar among all compositions. These facts evidenced that Cu2+ may be incorporated into the A and/or B sites of the perovskite structure, having both hardening and softening effects.

Compositional Design of Dielectric, Ferroelectric and Piezoelectric Properties of (K, Na)NbO3 and (Ba, Na)(Ti, Nb)O3 Based Ceramics Prepared by Different Sintering Routes

Science.gov (United States)

Eiras, José A.; Gerbasi, Rosimeire B. Z.; Rosso, Jaciele M.; Silva, Daniel M.; Cótica, Luiz F.; Santos, Ivair A.; Souza, Camila A.; Lente, Manuel H.

2016-01-01

Lead free piezoelectric materials are being intensively investigated in order to substitute lead based ones, commonly used in many different applications. Among the most promising lead-free materials are those with modified NaNbO3, such as (K, Na)NbO3 (KNN) and (Ba, Na)(Ti, Nb)O3 (BTNN) families. From a ceramic processing point of view, high density single phase KNN and BTNN ceramics are very difficult to sinter due to the volatility of the alkaline elements, the narrow sintering temperature range and the anomalous grain growth. In this work, Spark Plasma Sintering (SPS) and high-energy ball milling (HEBM), following heat treatments (calcining and sintering), in oxidative (O2) atmosphere have been used to prepare single phase highly densified KNN (“pure” and Cu2+ or Li1+ doped), with theoretical densities ρth > 97% and BTNN ceramics (ρth ~ 90%), respectively. Using BTTN ceramics with a P4mm perovskite-like structure, we showed that by increasing the NaNbO3 content, the ferroelectric properties change from having a relaxor effect to an almost “normal” ferroelectric character, while the tetragonality and grain size increase and the shear piezoelectric coefficients (k15, g15 and d15) improve. For KNN ceramics, the results reveal that the values for remanent polarization as well as for most of the coercive field are quite similar among all compositions. These facts evidenced that Cu2+ may be incorporated into the A and/or B sites of the perovskite structure, having both hardening and softening effects. PMID:28773304

Energy harvesting performance of piezoelectric ceramic and polymer nanowires.

Science.gov (United States)

Crossley, Sam; Kar-Narayan, Sohini

2015-08-28

Energy harvesting from ubiquitous ambient vibrations is attractive for autonomous small-power applications and thus considerable research is focused on piezoelectric materials as they permit direct inter-conversion of mechanical and electrical energy. Nanogenerators (NGs) based on piezoelectric nanowires are particularly attractive due to their sensitivity to small-scale vibrations and may possess superior mechanical-to-electrical conversion efficiency when compared to bulk or thin-film devices of the same material. However, candidate piezoelectric nanowires have hitherto been predominantly analyzed in terms of NG output (i.e. output voltage, output current and output power density). Surprisingly, the corresponding dynamical properties of the NG, including details of how the nanowires are mechanically driven and its impact on performance, have been largely neglected. Here we investigate all realizable NG driving contexts separately involving inertial displacement, applied stress T and applied strain S, highlighting the effect of driving mechanism and frequency on NG performance in each case. We argue that, in the majority of cases, the intrinsic high resonance frequencies of piezoelectric nanowires (∼tens of MHz) present no barrier to high levels of NG performance even at frequencies far below resonance (materials properties, for comparing piezoelectric NG performance under strain-driven and stress-driven conditions respectively. These figures of merit permit, for the first time, a general comparison of piezoelectric nanowires for NG applications that takes into account the nature of the mechanical excitation. We thus investigate the energy harvesting performance of prototypical piezoelectric ceramic and polymer nanowires. We find that even though ceramic and polymer nanowires have been found, in certain cases, to have similar energy conversion efficiencies, ceramics are more promising in strain-driven NGs while polymers are more promising for stress-driven NGs

Piezoelectric and dielectric properties of polymer-ceramic composites for sensors

NARCIS (Netherlands)

James, N.K.

2015-01-01

The main objective of this PhD thesis is to develop new routes and concepts for manufacturing piezoelectric ceramic-polymer composites with adequate piezoelectric properties while retaining ease of manufacturing and mechanical flexibility and explore new possibilities to maximize especially the

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

Science.gov (United States)

Miao, Hongchen; Chen, Xi; Cai, Hairong; Li, Faxin

2015-12-01

The face-shear ( d 36 ) 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 d 36 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 d 36 coefficients using both square patches and narrow bar samples, and the obtained values are consistent with that measured by a modified d 33 meter previously. For all samples, the pure d 36 mode can only appear near the resonance frequency, and the coupled d 36 - d 31 mode dominates off resonance. It is found that both the piezoelectric coefficient d 36 and the electromechanical coupling factor k 36 of soft PZT ceramics (PZT-5H and PZT-51) are considerably larger than those of the hard PZT ceramics (PZT-4). The obtained d 36 of 160-275pC/N, k 36 ˜ 0.24, and the mechanical quality factor Q 36 of 60-90 in soft PZT ceramics are comparable with the corresponding properties of the d 31 mode sample. Therefore, the d 36 mode in modified soft PZT ceramics is more promising for industrial applications such as face-shear resonators and shear horizontal wave generators.

Composition-Driven Phase Boundary and Piezoelectricity in Potassium-Sodium Niobate-Based Ceramics.

Science.gov (United States)

Zheng, Ting; Wu, Jiagang; Xiao, Dingquan; Zhu, Jianguo; Wang, Xiangjian; Lou, Xiaojie

2015-09-16

The piezoelectricity of (K,Na)NbO3 ceramics strongly depends on the phase boundary types as well as the doped compositions. Here, we systematically studied the relationships between the compositions and phase boundary types in (K,Na) (Nb,Sb)O3-Bi0.5Na0.5AO3 (KNNS-BNA, A=Hf, Zr, Ti, Sn) ceramics; then their piezoelectricity can be readily modified. Their phase boundary types are determined by the doped elements. A rhombohedral-tetragonal (R-T) phase boundary can be driven in the compositions range of 0.035≤BNH≤0.040 and 0.035≤BNZ≤0.045; an orthorhombic-tetragonal (O-T) phase boundary is formed in the composition range of 0.005≤BNT≤0.02; and a pure O phase can be only observed regardless of BNS content (≤0.01). In addition, the phase boundary types strongly affect their corresponding piezoelectricities. A larger d33 (∼440-450 pC/N) and a higher d33* (∼742-834 pm/V) can be attained in KNNS-BNA (A=Zr and Hf) ceramics due to the involvement of R-T phase boundary, and unfortunately KNNS-BNA (A=Sn and Ti) ceramics possess a relatively poor piezoelectricity (d33≤200 and d33*piezoelectricity and phase boundary types were also discussed. We believe that comprehensive research can design more excellent ceramic systems concerning potassium-sodium niobate.

Eigenstates of coupling factor and loss factor of piezoelectric ceramics

International Nuclear Information System (INIS)

Smits, J.G.

1978-01-01

A short history of piezoelectricity is given and its occurence in nature described. The physical background of piezoelectric loss is discussed together with how material coefficients like susceptibilities can be used to describe the relation between canonical variables and to determine the dissipation of energy. The piezoelectric coupling factor, the applications of the eigencoupling state, elastic and piezoelectric digenstates are dealt with. The composition of the measurement system is described and experimental values of ceramics given. (C.F.)

Nanoscale insight of high piezoelectricity in high-TC PMN-PH-PT ceramics

Science.gov (United States)

Zhu, Rongfeng; Zhang, Qihui; Fang, Bijun; Zhang, Shuai; Zhao, Xiangyong; Ding, Jianning

2018-03-01

The piezoelectric properties of the high-Curie temperature (high-TC) 0.15Pb(Mg1/3Nb2/3)O3-0.38PbHfO3-0.47PbTiO3 (0.15PMN-0.38PH-0.47PT) ceramics prepared by three different methods were compared. The 0.15PMN-0.38PH-0.47PT ceramics synthesized by the partial oxalate route exhibit the optimum properties, in which d33* = 845.3 pm/V, d33 = 456.2 pC/N, Kp = 67.2%, and TC = 291 °C. The nanoscale origin of the high piezoelectric response of the 0.15PMN-0.38PH-0.47PT ceramics was investigated by piezoresponse force microscopy (PFM) using the ceramics synthesized by the partial oxalate route. Large quantities of fine stripe submicron ferroelectric domains are observed, which form large island domains. In order to give further insights into the piezoelectric properties of the 0.15PMN-0.38PH-0.47PT ceramics from a microscopic point of view, the local poling experiments and local switching spectroscopy piezoresponse force microscopy (SS-PFM) were investigated, from which the local converse piezoelectric coefficient d33*(l) is calculated as 220 pm/V.

Dielectric, Piezoelectric, and Vibration Properties of the LiF-Doped (Ba0.95Ca0.05(Ti0.93Sn0.07O3 Lead-Free Piezoceramic Sheets

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Chien-Min Cheng

2018-01-01

Full Text Available By the conventional solid state reaction method, a small amount of lithium fluoride (LiF was used as the sintering promoter to improve the sintering and piezoelectric characteristics of (Ba0.95Ca0.05(Ti0.93Sn0.07O3 (BCTS lead-free piezoceramic sheets. Using X-ray diffraction (XRD and a scanning electron microscope (SEM, the inferences of the crystalline and surface microstructures were obtained and analyzed. Then, the impedance analyzer and d33-meter were used to measure the dielectric and piezoelectric characteristics. In this study, the optimum sintering temperature of the BCTS sheets decreased from 1450 °C to 1390 °C due to LiF doping. For the 0.07 wt % LiF-doped BCTS sheets sintered at 1390 °C, the piezoelectric constant (d33 is 413 pC/N, the electric–mechanical coupling coefficient (kp is 47.5%, the dielectric loss (tan δ is 3.9%, and the dielectric constant (εr is 8100, which are all close to or even better than that of the pure undoped BCTS ceramics. The Curie temperature also improved, from 85 °C for pure BCTS to 140 °C for BCTS–0.07 LiF sheets. Furthermore, by using the vibration system and fixing 1.5 g tip mass at the end of the sheets, as the vibration frequency is 20 Hz, the proposed piezoelectric ceramic sheets also reveal a good energy harvesting performance at the maximum output peak voltage of 4.6 V, which is large enough and can be applied in modern low-power electronic products.

Enhancing Piezoelectric Performance of CaBi2Nb2O9 Ceramics Through Microstructure Control

Science.gov (United States)

Chen, Huanbei; Zhai, Jiwei

2012-08-01

Calcium bismuth niobate (CaBi2Nb2O9, CBN) is a high-Curie-temperature ( T C) piezoelectric material with relatively poor piezoelectric performance. Attempts were made to enhance the piezoelectric and direct-current (DC) resistive properties of CBN ceramics by increasing their density and controlling their microstructural texture, which were achieved by combining the templated grain growth and hot pressing methods. The modified CBN ceramics with 97.5% relative density and 90.5% Lotgering factor had much higher piezoelectric constant ( d 33 = 20 pC/N) than those prepared by the normal sintering process ( d 33 = 6 pC/N). High-temperature alternating-current (AC) impedance spectroscopy of the CBN ceramics was measured by using an impedance/gain-phase analyzer. Their electrical resistivity was approximately 6.5 × 104 Ω cm at 600°C. Therefore, CBN ceramics can be used for high-temperature piezoelectric applications.

Strong piezoelectricity in (1 - x)(K0.4Na0.6)(Nb0.96Sb0.04)O3-xBi0.5K0.5Zr1-ySnyO3 lead-free binary system: identification and role of multiphase coexistence.

Science.gov (United States)

Zheng, Ting; Wu, Jiagang; Xiao, Dingquan; Zhu, Jianguo; Wang, Xiangjian; Xin, Lipeng; Lou, Xiaojie

2015-03-18

Here we report a strong piezoelectric activity in (1 - x)(K0.4Na0.6)(Nb0.96Sb0.04)O3-xBi0.5K0.5Zr1-ySnyO3 lead-free ceramics by designing different phase boundaries. The phase boundaries concerning rhombohedral-orthorhombic-tetragonal (R-O-T) and rhombohedral-tetragonal (R-T) multiphase coexistence were attained by changing BKZS and Sn contents and then were identified by the X-ray diffraction patterns as well as temperature-dependent permittivity and ν1 Raman modes associated with BO6 perovskite octahedron. A high strain (strain = 0.21-0.28% and d33* = 707-880 pm/V) and a strong piezoelectric coefficient (d33 = 415-460 pC/N) were shown in the ceramics located at the multiphase coexistence region. The reported results of this work are superior to that (d33* ∼ 570 pm/V and d33 ∼ 416 pC/N) of the textured (K,Na,Li)(Nb,Ta,Sb)O3 ceramics [Nature 2004, 432, 84]. We believe that the material system of this work will become one of the most promising candidates for piezoelectric actuators.

Effect of dielectrophoretic structuring on piezoelectric and pyroelectric properties of lead titanate-epoxy composites

NARCIS (Netherlands)

Khanbareh, H.; Zwaag, S. van der; Groen, W.A.

2014-01-01

Functional granular composites of lead titanate particles in an epoxy matrix prepared by dielectrophoresis show enhanced dielectric, piezoelectric and pyroelectric properties compared to 0-3 composites for different ceramic volume content from 10% to 50%. Two structuring parameters, the

Piezoelectric and electromechanical properties of ultrahigh temperature CaBi2Nb2O9 ceramics

International Nuclear Information System (INIS)

Wang, Jin-Feng; Zhang, Shujun; Shrout, Thomas R.; Wang, Chun-Ming

2009-01-01

The piezoelectric, dielectric, and electromechanical properties of the (KCe) co-substituted calcium bismuth niobate (CaBi 2 Nb 2 O 9 , CBN) were investigated. The piezoelectric activities of CBN ceramics were significantly enhanced and the dielectric loss tan δ decreased by (KCe) substitution. The Ca 0.9 (KCe) 0.05 Bi 2 Nb 2 O 9 ceramics possess the optimal piezoelectric properties, and the piezoelectric coefficient (d 33 ), Curie temperature (T C ), and electromechanical coupling factors (k p and k t ) were found to be 16 pC/N, 868 C, 8.6%, and 23.8%, respectively. The excellent dielectric and electromechanical spectra, together with the high piezoelectric activities and ultrahigh Curie temperature, make CBN ceramics promising candidates for high temperature piezoelectric applications. (copyright 2009 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Grain growth kinetics of textured-BaTiO3 ceramics

Indian Academy of Sciences (India)

Administrator

3Department of Physics and Materials Science, City University of Hong Kong, Hong Kong ... Abstract. Textured BaTiO3 (BT) ceramics were fabricated by templated grain growth method. Effects of ... approaches to improve electrical properties of lead-free ceramics. ... modification methods to enhance the piezoelectric pro-.

Nonlinear piezoelectricity in PZT ceramics for generating ultrasonic phase conjugate waves

Science.gov (United States)

Yamamoto; Kokubo; Sakai; Takagi

2000-03-01

We have succeeded in the generation of acoustic phase conjugate waves with nonlinear PZT piezoelectric ceramics and applied them to ultrasonic imaging systems. Our aim is to make a phase conjugator with 100% efficiency. For this purpose, it is important to clarify the mechanism of acoustic phase conjugation through nonlinear piezoelectricity. The process is explained by the parametric interaction via the third-order nonlinear piezoelectricity between the incident acoustic wave at angular frequency omega and the pump electric field at 2 omega. We solved the coupling equations including the third-ordered nonlinear piezoelectricity and theoretically derived the amplitude efficiency of the acoustic phase conjugation. We compared the efficiencies between the theoretical and experimental values for PZT ceramics with eight different compositions. Pb[(Zn1/3Nb2/3)(1 - x)Tix]O3 (X = 0.09, PZNT91/9) piezoelectric single crystals have been investigated for high-performance ultrasonic transducer application, because these have large piezoelectric constants, high electrical-mechanical coupling factors and high dielectric constants. We found that they have third-order nonlinear piezoelectric constants much larger than PZT and are hopeful that the material as a phase conjugator has over 100% efficiency.

Energy harvesting performance of piezoelectric ceramic and polymer nanowires

International Nuclear Information System (INIS)

Crossley, Sam; Kar-Narayan, Sohini

2015-01-01

Energy harvesting from ubiquitous ambient vibrations is attractive for autonomous small-power applications and thus considerable research is focused on piezoelectric materials as they permit direct inter-conversion of mechanical and electrical energy. Nanogenerators (NGs) based on piezoelectric nanowires are particularly attractive due to their sensitivity to small-scale vibrations and may possess superior mechanical-to-electrical conversion efficiency when compared to bulk or thin-film devices of the same material. However, candidate piezoelectric nanowires have hitherto been predominantly analyzed in terms of NG output (i.e. output voltage, output current and output power density). Surprisingly, the corresponding dynamical properties of the NG, including details of how the nanowires are mechanically driven and its impact on performance, have been largely neglected. Here we investigate all realizable NG driving contexts separately involving inertial displacement, applied stress T and applied strain S, highlighting the effect of driving mechanism and frequency on NG performance in each case. We argue that, in the majority of cases, the intrinsic high resonance frequencies of piezoelectric nanowires (∼tens of MHz) present no barrier to high levels of NG performance even at frequencies far below resonance (<1 kHz) typically characteristic of ambient vibrations. In this context, we introduce vibrational energy harvesting (VEH) coefficients η S and η T , based on intrinsic materials properties, for comparing piezoelectric NG performance under strain-driven and stress-driven conditions respectively. These figures of merit permit, for the first time, a general comparison of piezoelectric nanowires for NG applications that takes into account the nature of the mechanical excitation. We thus investigate the energy harvesting performance of prototypical piezoelectric ceramic and polymer nanowires. We find that even though ceramic and polymer nanowires have been found, in

Piezoelectric textured ceramics: Effective properties and application to ultrasonic transducers.

Science.gov (United States)

Levassort, Franck; Pham Thi, Mai; Hemery, Henry; Marechal, Pierre; Tran-Huu-Hue, Louis-Pascal; Lethiecq, Marc

2006-12-22

Piezoelectric textured ceramics obtained by homo-template grain growth (HTGG) were recently demonstrated. A simple model with several assumptions has been used to calculate effective parameters of these new materials. Different connectivities have been simulated to show that spatial arrangements between the considered phases have little influence on the effective parameters, even through the 3-0 connectivity delivers the highest electromechanical thickness factor. A transducer based on a textured ceramic sample has been fabricated and characterised to show the efficiency of these piezoelectric materials. Finally, in a single element transducer configuration, simulation shows an improvement of 2 dB sensitivity for a transducer made with textured ceramic in comparison with a similar transducer design based on standard soft PZT (at equivalent bandwidths).

Piezoelectric Materials Synthesized by the Hydrothermal Method and Their Applications

Directory of Open Access Journals (Sweden)

Takeshi Morita

2010-12-01

Full Text Available Synthesis by the hydrothermal method has various advantages, including low reaction temperature, three-dimensional substrate availability, and automatic polarization alignment during the process. In this review, powder synthesis, the fabrication of piezoelectric thin films, and their applications are introduced. A polycrystalline lead zirconate titanate (PZT thin film was applied to a micro ultrasonic motor, and an epitaxial lead titanate (PbTiO3 thin film was estimated as a ferroelectric data storage medium. Ferroelectric and piezoelectric properties were successfully obtained for epitaxial PbTiO3 films. As lead-free piezoelectric powders, KNbO3 and NaNbO3 powders were synthesized by the hydrothermal method and sintered together to form (K,NaNbO3 ceramics, from which reasonable piezoelectric performance was achieved.

UV laser micromachining of piezoelectric ceramic using a pulsed Nd:YAG laser

International Nuclear Information System (INIS)

Zeng, D.W.; Xie, C.S.; Li, K.; Chan, H.L.W.; Choy, C.L.; Yung, K.C.

2004-01-01

UV laser (λ=355 nm) ablation of piezoelectric lead zirconate titanate (PZT) ceramics in air has been investigated under different laser parameters. It has been found that there is a critical pulse number (N=750). When the pulse number is smaller than the critical value, the ablation rate decreases with increasing pulse number. Beyond the critical value, the ablation rate becomes constant. The ablation rate and concentrations of O, Zr and Ti on the ablated surface increase with the laser fluence, while the Pb concentration decreases due to the selective evaporation of PbO. The loss of the Pb results in the formation of a metastable pyrochlore phase. ZrO 2 was detected by XPS in the ablated zone. Also, the concentrations of the pyrochlore phase and ZrO 2 increase with increasing laser fluence. These results clearly indicate that the chemical composition and phase structure in the ablated zone strongly depend on the laser fluence. The piezoelectric properties of the cut PZT ceramic samples completely disappear due to the loss of the Pb and the existence of the pyrochlore phase. After these samples were annealed at 1150 C for 1 h in a PbO-controlled atmosphere, their phase structure and piezoelectric properties were recovered again. Finally, 1-3 and concentric-ring 2-2 PZT/epoxy composites were fabricated by UV laser micromachining and their thickness modes were measured by impedance spectrum analysis and a d 33 meter. Both composites show high piezoelectric properties. (orig.)

Design, fabrication, and properties of 2-2 connectivity cement/polymer based piezoelectric composites with varied piezoelectric phase distribution

International Nuclear Information System (INIS)

Dongyu, Xu; Xin, Cheng; Shifeng, Huang; Banerjee, Sourav

2014-01-01

The laminated 2-2 connectivity cement/polymer based piezoelectric composites with varied piezoelectric phase distribution were fabricated by employing Lead Zirconium Titanate ceramic as active phase, and mixture of cement powder, epoxy resin, and hardener as matrix phase with a mass proportion of 4:4:1. The dielectric, piezoelectric, and electromechanical coupling properties of the composites were studied. The composites with large total volume fraction of piezoelectric phase have large piezoelectric strain constant and relative permittivity, and the piezoelectric and dielectric properties of the composites are independent of the dimensional variations of the piezoelectric ceramic layer. The composites with small total volume fraction of piezoelectric phase have large piezoelectric voltage constant, but also large dielectric loss. The composite with gradually increased dimension of piezoelectric ceramic layer has the smallest dielectric loss, and that with the gradually increased dimension of matrix layer has the largest piezoelectric voltage constant. The novel piezoelectric composites show potential applications in fabricating ultrasonic transducers with varied surface vibration amplitude of the transducer

Loss Factor Characterization Methodology for Piezoelectric Ceramics

International Nuclear Information System (INIS)

Zhuang Yuan; Ural, Seyit O; Uchino, Kenji

2011-01-01

The key factor for the miniaturization of piezoelectric devices is power density, which is limited by the heat generation or loss mechanisms. There are three loss components for piezoelectric vibrators, i.e., dielectric, elastic and piezoelectric losses. The mechanical quality factor, determined by these three factors, is the figure of merit in the sense of loss or heat generation. In this paper, quality factors of resonance and antiresonance for k 31 , k 33 , and k 15 vibration modes are derived, and the methodology to determine loss factors in various directions is provided. For simplicity, we focus on materials with ∞mm (equivalent to 6mm) crystal symmetry for deriving the loss factors of polycrystalline ceramics, and 16 different loss factors among total 20 can be obtained from the admittance/ impedance measurements.

Nanodomain Engineered (K, Na)NbO3 Lead-Free Piezoceramics: Enhanced Thermal and Cycling Reliabilities

DEFF Research Database (Denmark)

Yao, Fang-Zhou; Wang, Ke; Cheng, Li-Qian

2015-01-01

- based materials, accepting the drawbacks of high temperature and cycling instabilities. Here, we present that CaZrO3-modified (K, Na)NbO3 piezoceramics not only possess excellent performance at ambient conditions benefiting from nanodomain engineering, but also exhibit superior stability against......The growing environmental concerns have been pushing the development of viable green alternatives for lead-based piezoceramics to be one of the priorities in functional ceramic materials. A polymorphic phase transition has been utilized to enhance piezoelectric properties of lead-free (K, Na)NbO3...... temperature fluctuation and electrical fatigue cycling. It was found that the piezoelectric coefficient d33 is temperature independent under 4 kV/mm, which can be attributed to enhanced thermal stability of electric field engineered domain configuration; whereas the electric field induced strain exhibits...

Effect of electrical and mechanical poling history on domain orientation and piezoelectric properties of soft and hard PZT ceramics

International Nuclear Information System (INIS)

Marsilius, Mie; Granzow, Torsten; Jones, Jacob L

2011-01-01

The superior piezoelectric properties of all polycrystalline ferroelectrics are based on the extent of non-180 0 domain wall motion under electrical and mechanical poling loads. To distinguish between 180 0 and non-180 0 domain wall motion in a soft-doped and a hard-doped lead zirconate titanate (PZT) ceramic, domain texture measurements were performed using x-ray and neutron diffraction after different loading procedures. Comparing the results to measurements of the remanent strain and piezoelectric coefficient allowed the differentiation between different microstructural contributions to the macroscopic parameters. Both types of ceramic showed similar behavior under electric field, but the hard-doped material was more susceptible to mechanical load. A considerable fraction of the piezoelectric coefficient originated from poling by the preferred orientation of 180 0 domains.

Effect of electrical and mechanical poling history on domain orientation and piezoelectric properties of soft and hard PZT ceramics

Science.gov (United States)

Marsilius, Mie; Granzow, Torsten; Jones, Jacob L.

2011-02-01

The superior piezoelectric properties of all polycrystalline ferroelectrics are based on the extent of non-180° domain wall motion under electrical and mechanical poling loads. To distinguish between 180° and non-180° domain wall motion in a soft-doped and a hard-doped lead zirconate titanate (PZT) ceramic, domain texture measurements were performed using x-ray and neutron diffraction after different loading procedures. Comparing the results to measurements of the remanent strain and piezoelectric coefficient allowed the differentiation between different microstructural contributions to the macroscopic parameters. Both types of ceramic showed similar behavior under electric field, but the hard-doped material was more susceptible to mechanical load. A considerable fraction of the piezoelectric coefficient originated from poling by the preferred orientation of 180° domains.

Growth of Ca, Zr co-doped BaTiO3 lead-free ferroelectric single crystal and its room-temperature piezoelectricity

Directory of Open Access Journals (Sweden)

Donglin Liu

2017-09-01

Full Text Available Lead-free Ca, Zr co-doped BaTiO3 (BCZT single crystal with a dimension up to 2mm×2mm×2mm was grown by a spontaneous nucleation technique using KF as the flux. The composition of the studied single crystal was defined to be Ba0.798Ca0.202Zr0.006Ti0.994O3, corresponding to a tetragonal phase at room temperature. The oriented single crystal exhibited a quasi-static piezoelectric constant of approximately 232 pC/N. The effective piezoelectric coefficient d33* of the single domain crystal obtained under a unipolar electric field of 35 kV/cm was 179 pm/V. Rayleigh analysis was used to identify the intrinsic and extrinsic contributions to the room-temperature piezoelectricity of BCZT single crystal. The extrinsic contribution was estimated up to 40% due to the irreversible domain wall movement. Furthermore a sixth-order polynomial of Landau expansion was employed to analyze the intrinsic contribution to piezoelectricity of BCZT single crystal. The large energy barriers inhibited polarization rotations, leading to the relatively low piezoelectricity.

Influence of niobium substitution on structural and opto-electrical properties of BNKT piezoelectric ceramics

Energy Technology Data Exchange (ETDEWEB)

Chauhan, Vidhi [Electroceramics Research Group, Department of Physics, Birla Institute of Technology, Mesra, Ranchi (India); Ghosh, S.K., E-mail: saritghosh@gmail.com [Electroceramics Research Group, Department of Physics, Birla Institute of Technology, Mesra, Ranchi (India); Hussain, Ali [School of Advanced Materials Engineering, Changwon National University, Gyeong-Nam, 641-773 (Korea, Republic of); Rout, S.K., E-mail: skrout@bitmesra.ac.in [Electroceramics Research Group, Department of Physics, Birla Institute of Technology, Mesra, Ranchi (India)

2016-07-25

Lead free niobium modified piezoelectric ceramics Bi{sub 0.5}Na{sub 0.25}K{sub 0.25}Nb{sub x}Ti{sub 1-x}O{sub 3} (BNKT) (x = 0.0, 0.015 and 0.025) compositions along with their structural and opto-electrical properties are investigated. At room temperature Rietveld refinement analysis on x-ray diffraction data revealed the evidence of tetragonal (P4mm) + cubic (Pm3m) mixed phases at 0.015Nb-BNKT composition and at higher niobium concentration it moves towards cubic phase. Presence of local disorder controls the Raman active vibrational modes along with excitation and emission spectra in these materials. The temperature dependence dielectric constant is investigated in the frequency range of 1 kHz–100 kHz. The broadening of dielectric peak and frequency dependence behavior indicated a relaxor property in these materials. Induced A-site vacancies and coexistence of tetragonal-pseudocubic phases lower the depolarization temperature (T{sub d}) with niobium concentration. The structural mix phases have been correlated with the piezoelectric coefficients and the composition x = 0.015 depicts the better piezoelectric properties amongst the studied compositions which is endorsed to the mixed symmetry of tetragonal and cubic phases. - Highlights: • Coexistence of polar and non-polar phases in Nb doped BNKT materials. • Structural instability and lattice disorder controls the opto-electrical properties. • Broadening and shifting of dielectric peaks highlighted the relaxor behavior. • High value of ferroelectric and piezoelectric coefficients at x = 0.015 composition.

Structural, dielectric and piezoelectric study of Ca-, Zr-modified ...

Indian Academy of Sciences (India)

Home; Journals; Bulletin of Materials Science; Volume 40; Issue 5. Structural, dielectric and piezoelectric study of Ca-, Zr-modified BaTiO 3 lead-free ceramics. H MSOUNI A TACHAFINE M EL AATMANI D FASQUELLE J C CARRU M EL HAMMIOUI M RGUITI A ZEGZOUTI A OUTZOURHIT M DAOUD. Volume 40 Issue 5 ...

High-power piezoelectric characteristics of textured bismuth layer structured ferroelectric ceramics.

Science.gov (United States)

Ogawa, Hirozumi; Kawada, Shinichiro; Kimura, Masahiko; Shiratsuyu, Kousuke; Sakabe, Yukio

2007-12-01

Abstract-The high-power piezoelectric characteristics in h001i oriented ceramics of bismuth layer structured ferroelectrics (BLSF), SrBi(2)Nb(2)O(9) (SBN), (Bi,La)(4)Ti(3)O(12) (BLT), and CaBi(4)Ti(4)O(15) (CBT), were studied by a constant voltage driving method. These textured ceramics were fabricated by a templated grain growth (TGG) method, and their Lotgering factors were 95%, 97%, and 99%, respectively. The vibration velocities of the longitudinal mode (33-mode) increased proportionally to an applied electric field up to 2.5 m/s in these textured BLSF ceramics, although, the vibration velocity of the 33-mode was saturated at more than 1.0 m/s in the Pb(Mn,Nb)O(3)-PZT ceramics. The resonant frequencies were constant up to the vibration velocity of 2.5 m/s in the SBN and CBT textured ceramics; however, the resonant frequency decreased with increasing over the vibration velocity of 1.5 m/s in the BLT textured ceramics. The dissipation power density of the BLT was almost the same as that of the Pb(Mn,Nb)O(3)-PZT ceramics. However, the dissipation power densities of the SBN and CBT were lower than those of the BLT and Pb(Mn,Nb)O(3)-PZT ceramics. The textured SBN and CBT ceramics are good candidates for high-power piezoelectric applications.

Development of Novel Piezoelectric Biosensor Using PZT Ceramic Resonator for Detection of Cancer Markers.

Science.gov (United States)

Su, Li; Fong, Chi-Chun; Cheung, Pik-Yuan; Yang, Mengsu

2017-01-01

A novel biosensor based on piezoelectric ceramic resonator was developed for direct detection of cancer markers in the study. For the first time, a commercially available PZT ceramic resonator with high resonance frequency was utilized as transducer for a piezoelectric biosensor. A dual ceramic resonators scheme was designed wherein two ceramic resonators were connected in parallel: one resonator was used as the sensing unit and the other as the control unit. This arrangement minimizes environmental influences including temperature fluctuation, while achieving the required frequency stability for biosensing applications. The detection of the cancer markers Prostate Specific Antigen (PSA) and α-Fetoprotein (AFP) was carried out through frequency change measurement. The device showed high sensitivity (0.25 ng/ml) and fast detection (within 30 min) with small samples (1 μl), which is compatible with the requirements of clinical measurements. The results also showed that the ceramic resonator-based piezoelectric biosensor platform could be utilized with different chemical interfaces, and had the potential to be further developed into biosensor arrays with different specificities for simultaneous detection of multiple analytes.

Evolution of bias field and offset piezoelectric coefficient in bulk lead zirconate titanate with fatigue

International Nuclear Information System (INIS)

Zhang Yong; Baturin, Ivan S.; Aulbach, Emil; Lupascu, Doru C.; Kholkin, Andrei L.; Shur, Vladimir Ya.; Roedel, Juergen

2005-01-01

Hysteresis loops of the piezoelectric coefficient, d 33 =f(E 3 ), are measured on virgin and fatigued lead zirconate titanate ceramics. Four parameters are directly extracted from the measurements: internal bias field E b , offset piezoelectric coefficient d offset , coercive field E c , and remnant piezoelectric coefficient d r . The reduction in d r displays the decreasing switchable polarization with fatigue cycling. E b and d offset are found to be linearly related. After thermal annealing, both offsets disappear, while the increase in E c and the reduction in d r withstand annealing. The microscopic entities responsible for the offsets are less stable than those for reduced switching

Improved ferroelectric/piezoelectric properties and bright green/UC red emission in (Li,Ho)-doped CaBi4Ti4O15 multifunctional ceramics with excellent temperature stability and superior water-resistance performance.

Science.gov (United States)

Xiao, Ping; Guo, Yongquan; Tian, Mijie; Zheng, Qiaoji; Jiang, Na; Wu, Xiaochun; Xia, Zhiguo; Lin, Dunmin

2015-10-21

Multifunctional materials based on rare earth ion doped ferro/piezoelectrics have attracted considerable attention in recent years. In this work, new lead-free multifunctional ceramics of Ca1-x(LiHo)x/2Bi4Ti4O15 were prepared by a conventional solid-state reaction method. The great multi-improvement in ferroelectricity/piezoelectricity, down/up-conversion luminescence and temperature stability of the multifunctional properties is induced by the partial substitution of (Li0.5Ho0.5)(2+) for Ca(2+) ions in CaBi4Ti4O15. All the ceramics possess a bismuth-layer structure, and the crystal structure of the ceramics is changed from a four layered bismuth-layer structure to a three-layered structure with the level of (Li0.5Ho0.5)(2+) increasing. The ceramic with x = 0.1 exhibits simultaneously, high resistivity (R = 4.51 × 10(11)Ω cm), good piezoelectricity (d33 = 10.2 pC N(-1)), high Curie temperature (TC = 814 °C), strong ferroelectricity (Pr = 9.03 μC cm(-2)) and enhanced luminescence. These behaviours are greatly associated with the contribution of (Li0.5Ho0.5)(2+) in the ceramics. Under the excitation of 451 nm light, the ceramic with x = 0.1 exhibits a strong green emission peak centered at 545 nm, corresponding to the transition of the (5)S2→(5)I8 level in Ho(3+) ions, while a strong red up-conversion emission band located at 660 nm is observed under the near-infrared excitation of 980 nm at room temperature, arising from the transition of (5)F5→(5)I8 levels in Ho(3+) ions. Surprisingly, the excellent temperature stability of ferroelectricity/piezoelectricity/luminescence and superior water-resistance behaviors of piezoelectricity/luminescence are also obtained in the ceramic with x = 0.1. Our study suggests that the present ceramics may have potential applications in advanced multifunctional devices at high temperature.

Grain Oriented Perovskite Layer Structure Ceramics for High-Temperature Piezoelectric Applications

Science.gov (United States)

Fuierer, Paul Anton

The perovskite layer structure (PLS) compounds have the general formula (A^{2+}) _2(B^{5+})_2 O_7, or (A^ {3+})_2(B^{4+ })_2O_7, and crystallize in a very anisotropic layered structure consisting of parallel slabs made up of perovskite units. Several of these compounds possess the highest Curie temperatures (T_{rm c} ) of any known ferroelectrics. Two examples are Sr_2Nb_2O _7 with T_{rm c} of 1342^circC, and La_2Ti_2O _7 with T_{rm c} of 1500^circC. This thesis is an investigation of PLS ceramics and their feasibility as a high temperature transducer material. Piezoelectricity in single crystals has been measured, but the containerless float zone apparatus necessary to grow high quality crystals of these refractory compounds is expensive and limited to a small number of research groups. Previous attempts to pole polycrystalline Sr_2Nb _2O_7 have failed, and to this point piezoelectricity has been absent. The initiative taken in this research was to investigate PLS ceramics by way of composition and processing schemes such that polycrystalline bodies could be electrically poled. The ultimate objective then was to demonstrate piezoelectricity in PLS ceramics, especially at high temperatures. Donor-doping of both La_2Ti _2O_7 and Sr_2Nb_2O _7 was found to increase volume resistivities at elevated temperatures, an important parameter to consider during the poling process. Sr_2Ta _2O_7 (T _{rm c} = -107 ^circC) was used to make solid solution compositions with moderately high Curie temperatures, of about 850^circC, and lower coercive fields. A hot-forging technique was employed to produce ceramics with high density (>99% of theoretical) and high degree of grain orientation (>90%). Texturing was characterized by x-ray diffraction and microscopy. Considerable anisotropy was observed in physical and electrical properties, including thermal expansion, resistivity, dielectric constant, and polarization. The direction perpendicular to the forging axis proved to be the

A modified barbell-shaped PNN-PZT-PIN piezoelectric ceramic energy harvester

Science.gov (United States)

Gao, Xiangyu; Wu, Jingen; Yu, Yang; Dong, Shuxiang

2017-11-01

The quaternary system of relaxor-ferroelectric based Pb(Ni1/3Nb2/3)O3-Pb(ZrxTi1-x)O3-Pb(In0.5Nb0.5)O3 (PNN-PZT-PIN) piezoelectric ceramic at the morphotropic phase boundary was investigated via the solid reaction method. The optimized ceramic with excellent electric properties of ɛr = 8084, d33 = 977 pC/N, kp = 0.61, and Ec = 3.0 kV/cm was fabricated into d33-mode discs with separated surface electrodes, which were arranged in a series connection and, then as a piezo-stack, assembled into a barbell-shaped energy harvester that could bear a strong mechanical vibration. It is found that under a vibration mass-induced bending moment, the energy harvester produces an open circuit voltage of 26.4 Vp-p at the acceleration of 2.5 g at a load of 1.56 MΩ, which is two times higher in comparison to one without surface electrode separation. Its power output is 30 μW at the acceleration of 1 g and 104 μW at 2.5 g, which are even six times higher than that of a previously reported barbell-shaped energy harvester at room-temperature with the same acceleration. The enhanced power output can be attributed to (i) the excellent piezoelectric response of PNN-PZT-PIN ceramic and (ii) harvesting positive and negative charges from the separated surface electrodes other than a full surface electrode on piezoelectric discs under bending moment. Furthermore, the practical test was performed within a car engine, which shows that the PNN-PZT-PIN piezoelectric ceramic is a promising candidate for vibration energy harvesting.

An optical fiber Bragg grating and piezoelectric ceramic voltage sensor

Science.gov (United States)

Yang, Qing; He, Yanxiao; Sun, Shangpeng; Luo, Mandan; Han, Rui

2017-10-01

Voltage measurement is essential in many fields like power grids, telecommunications, metallurgy, railways, and oil production. A voltage-sensing unit, consisting of fiber Bragg gratings (FBGs) and piezoelectric ceramics, based on which an optical over-voltage sensor was proposed and fabricated in this paper. No demodulation devices like spectrometer or Fabry-Perot filter were needed to gain the voltage signal, and a relatively large sensing frequency range was acquired in this paper; thus, the cost of the sensing system is more acceptable in engineering application. The voltage to be measured was directly applied to the piezoelectric ceramic, and deformation of the ceramics and the grating would be caused because of the inverse piezoelectric effect. With a reference grating, the output light intensity change will be caused by the FBG center wavelength change; thus, the relationship between the applied voltage and the output light intensity was established. Validation of the sensor was accomplished in the frequency range from 50 Hz to 20 kHz and switching impulse waves with a test platform; good linearity of the input-output characteristic was achieved. A temperature validation test was completed, showing that the sensor maintains good temperature stability. Experimental results show that the optical over-voltage sensor can be used for voltage monitoring, and if applied with a voltage divider, the sensor can be used to measure high voltage.

An optical fiber Bragg grating and piezoelectric ceramic voltage sensor.

Science.gov (United States)

Yang, Qing; He, Yanxiao; Sun, Shangpeng; Luo, Mandan; Han, Rui

2017-10-01

Voltage measurement is essential in many fields like power grids, telecommunications, metallurgy, railways, and oil production. A voltage-sensing unit, consisting of fiber Bragg gratings (FBGs) and piezoelectric ceramics, based on which an optical over-voltage sensor was proposed and fabricated in this paper. No demodulation devices like spectrometer or Fabry-Perot filter were needed to gain the voltage signal, and a relatively large sensing frequency range was acquired in this paper; thus, the cost of the sensing system is more acceptable in engineering application. The voltage to be measured was directly applied to the piezoelectric ceramic, and deformation of the ceramics and the grating would be caused because of the inverse piezoelectric effect. With a reference grating, the output light intensity change will be caused by the FBG center wavelength change; thus, the relationship between the applied voltage and the output light intensity was established. Validation of the sensor was accomplished in the frequency range from 50 Hz to 20 kHz and switching impulse waves with a test platform; good linearity of the input-output characteristic was achieved. A temperature validation test was completed, showing that the sensor maintains good temperature stability. Experimental results show that the optical over-voltage sensor can be used for voltage monitoring, and if applied with a voltage divider, the sensor can be used to measure high voltage.

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

Science.gov (United States)

Miao, Hongchen; Li, Faxin

2015-09-01

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 Z x t ±45 ° direction, we realized d36 coefficients up to 206 pC/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.

Electric Field-Induced Large Strain in Ni/Sb-co Doped (Bi0.5Na0.5) TiO3-Based Lead-Free Ceramics

Science.gov (United States)

Li, Liangliang; Hao, Jigong; Xu, Zhijun; Li, Wei; Chu, Ruiqing

2018-02-01

Lead-free piezoelectric ceramics (Bi0.5Na0.5)0.935Ba0.065Ti1- x (Ni0.5Sb0.5) x O3 (BNBT6.5- xNS) have been fabricated using conventional solid sintering technique. The effect of (Ni, Sb) doping on the phase structure and electrical properties of BNBT6.5 ceramics were systematically investigated. Results show that the addition of (Ni, Sb) destroyed the ferroelectric long-range order of BNBT6.5 and shifted the ferroelectric-relaxor transition temperature ( T F-R) down to room temperature. Thus, this process induced an ergodic relaxor phase at zero field in samples with x = 0.005. Under the electric field, the ergodic relaxor phase could reversibly transform to ferroelectric phase, which promotes the strain response with peak value of 0.38% (at 80 kV/cm, corresponding to d 33 * = 479 pm/V) at x = 0.005. Temperature-dependent measurements of both polarization and strain confirmed that the large strain originated from a reversible field-induced ergodic relaxor to ferroelectric phase transformation. The proposed material exhibits potential for nonlinear actuators.

Spectroscopic studies on (Ba,Ca)(Ti,Zr)O3 ferroelectric ceramics with high piezoelectric coefficients

International Nuclear Information System (INIS)

Archana Kumar; Sreenivas, K.

2013-01-01

In recent year non lead-based multi component ceramics consisting Ba(Ti 0.8 Zr 0.2 )O 3- (Ba 0.7 Ca 0.3 )TiO 3 have been found to exhibit high piezoelectric coefficients comparable to those of PZT, and there is a lot interest to understand nature of phase transition in these novel compositions. In the present study 0.5Ba(Ti 0.8 Zr 0.2 )O 3- 0.5(Ba 0.7 Ca 0.3 )TiO 3 ceramic composition calcinated and sintered at different temperatures has been investigated. The ceramics are prepared from the raw powders and reacted by a solid state reaction method. Spectroscopic methods including DTA/TGA, FTIR and Raman spectroscopy been used to understand the changes occurring in the chemical and structural properties during processing. The nature of polymorphic phase transition has been studied through the temperature dependent Raman spectroscopy. The de-poling characteristics with temperature have been studied to assess their usefulness for high temperature transducer applications, and their ferroelectric properties have been studied. This new composition exhibits high piezoelectric (d 33 ), and the transition temperature is low around 120℃. (author)

Electromechanical properties of textured K0.5Na0.5NbO3 ceramics

OpenAIRE

Pinho, Rui Manuel de Oliveira

2014-01-01

This work is about lead-free ceramic materials intended for electromechanical applications and candidates to replace lead-based electroceramics. One of the most widely used piezoelectric ceramics is lead zirconate titanate (PZT). However, it contains more than 60% of lead and it is toxic for humans and environment. In 2003, a directive from European Union has prohibited the use of potentially hazardous elements as lead. Due to the lack of competitive materials for PZT replacement an exception...

Properties of PZT-Based Piezoelectric Ceramics Between -150 and 250 C

Science.gov (United States)

Hooker, Matthew W.

1998-01-01

The properties of three PZT-based piezoelectric ceramics and one PLZT electrostrictive ceramic were measured as a function of temperature. In this work, the dielectric, ferroelectric polarization versus electric field, and piezoelectric properties of PZT-4, PZT-5A, PZT-5H, and PLZT-9/65/35 were measured over a temperature range of -150 to 250 C. In addition to these measurements, the relative thermal expansion of each composition was measured from 25 to 600 C and the modulus of rupture of each material was measured at room temperature. This report describes the experimental results and compares and contrasts the properties of these materials with respect to their applicability to intelligent aerospace systems.

Structural and piezoelectric properties of aged 1-mol% Li2O-excess (Na0.51K0.47Li0.02)(Nb0.8Ta0.2)O3 ceramics

International Nuclear Information System (INIS)

Moon, Sang-Ho; Yun, Seok-Woo; Ham, Yong-Su; Lee, Young-Hie; Nam, Song-Min; Koh, Jung-Hyuk; Jeong, Soon-Jong; Kim, Min-Soo

2010-01-01

One (1)-mol% Li 2 O-excess (Na 0.51 K 0.47 Li 0.02 )(Nb 0.8 Ta 0.2 )O 3 lead-free piezoelectric ceramics were aged under different unipolar electric fields. Unipolar electric fields of 3, 5, and 7 kV/cm were applied to the specimens to accelerate the electric aging behavior. By employing a unipolar electric field for the piezoelectric actuators, we were able to remove undesirable heating problem from the relaxation current in the ferroelectric domain motions. To accelerate the aging test, we used an applied electric fields with a frequency of 910 Hz. To earn enough time for charging and discharging, we used an accurate time constant for the equivalent model for the piezoelectric actuators. X-ray diffraction analyses were carried out to determine the structural aging behavior of the poled piezoelectric specimens. As the piezoelectric specimens were exposed to high electric fields for aging tests, the actuators lost their tetragonality and took on a pseudo-cubic structure. The cycling dependent piezoelectric coefficient and electromechnical coupling coefficient followed a stretched exponential law as aging process.

Mechanical confinement for improved energy storage density in BNT-BT-KNN lead-free ceramic capacitors

Directory of Open Access Journals (Sweden)

Aditya Chauhan

2014-08-01

Full Text Available With the advent of modern power electronics, embedded circuits and non-conventional energy harvesting, the need for high performance capacitors is bound to become indispensible. The current state-of-art employs ferroelectric ceramics and linear dielectrics for solid state capacitance. However, lead-free ferroelectric ceramics propose to offer significant improvement in the field of electrical energy storage owing to their high discharge efficiency and energy storage density. In this regards, the authors have investigated the effects of compressive stress as a means of improving the energy storage density of lead-free ferroelectric ceramics. The energy storage density of 0.91(Bi0.5Na0.5TiO3-0.07BaTiO3-0.02(K0.5Na0.5NbO3 ferroelectric bulk ceramic was analyzed as a function of varying levels of compressive stress and operational temperature .It was observed that a peak energy density of 387 mJ.cm-3 was obtained at 100 MPa applied stress (25oC. While a maximum energy density of 568 mJ.cm-3 was obtained for the same stress at 80oC. These values are indicative of a significant, 25% and 84%, improvement in the value of stored energy compared to an unloaded material. Additionally, material's discharge efficiency has also been discussed as a function of operational parameters. The observed phenomenon has been explained on the basis of field induced structural transition and competitive domain switching theory.

The history of ceramic filters.

Science.gov (United States)

Fujishima, S

2000-01-01

The history of ceramic filters is surveyed. Included is the history of piezoelectric ceramics. Ceramic filters were developed using technology similar to that of quartz crystal and electro-mechanical filters. However, the key to this development involved the theoretical analysis of vibration modes and material improvements of piezoelectric ceramics. The primary application of ceramic filters has been for consumer-market use. Accordingly, a major emphasis has involved mass production technology, leading to low-priced devices. A typical ceramic filter includes monolithic resonators and capacitors packaged in unique configurations.

Development of a stress sensor based on the piezoelectric lead zirconate titanate for impact stress measurement

Science.gov (United States)

Liu, Yiming; Xu, Bin; Li, Lifei; Li, Bing

2012-04-01

The measurement of stress of concrete structures under impact loading and other strong dynamic loadings is crucial for the monitoring of health and damage detection. Due to its main advantages including availability, extremely high rigidity, high natural frequency, wide measuring range, high stability, high reproducibility, high linearity and wide operating temperature range, piezoelectric (Lead Zirconate Titanate, PZT) ceramic materials has been a widely used smart material for both sensing and actuation for monitoring and control in engineering structures. In this paper, a kind of stress sensor based on piezoelectric ceramics for impact stress measuring of concrete structures is developed. Because the PZT is fragile, in order to employ it for the health monitoring of concrete structures, special handling and treatment should be taken to protect the PZT and to make it survive and work properly in concrete. The commercially available PZT patch with lead wires is first applied with an insulation coating to prevent water and moisture damage, and then is packaged by jacketing it by two small precasted cylinder concrete blocks with enough strength to form a smart aggregate (SA). The employed PZT patch has a dimension of 10mm x 10mm x 0.3mm. In order to calibrate the PZT based stress sensor for impact stress measuring, a dropping hammer was designed and calibration test on the sensitivity of the proposed transducer was carried out with an industry charge amplifier. The voltage output of the stress sensor and the impact force under different free falling heights and impact mass were recorded with a high sampling rate data acquisition system. Based on the test measurements, the sensibility of the PZT based stress sensor was determined. Results show that the output of the PZT based stress sensor is proportional to the stress level and the repeatability of the measurement is very good. The self-made piezoelectric stress sensor can be easily embedded in concrete and provide

Evolution of phase structure and giant strain at low driving fields in Bi-based lead-free incipient piezoelectrics

International Nuclear Information System (INIS)

Maqbool, Adnan; Hussain, Ali; Malik, Rizwan Ahmed; Rahman, Jamil Ur; Zaman, Arif; Song, Tae Kwon; Kim, Won-Jeong; Kim, Myong-Ho

2015-01-01

Graphical abstract: - Highlights: • Nb-doped BNBT–SZ ceramics were prepared by conventional solid state method. • A giant normalized strain of 825 pm/V at 4 kV/mm was achieved. • A large strain of 0.20% triggered at a relatively low field of 3 kV/mm. • Highest strain obtained in BNT-based ceramics at such a low driving field. • Ferroelectric to ergodic-relaxor phase transition occurred with Nb-doping. - Abstract: Lead-free 0.99[(Bi 0.5 Na 0.5 ) 0.935 Ba 0.065 Ti (1–x) Nb x O 3 ]–0.01SrZrO 3 (BNBTNb100x–SZ, with Nb100x = 0–1) ceramics were prepared by the conventional mixed oxide route. X-ray diffraction and Raman scattering was utilized for the structural evolution of Nb-modified BNBT–SZ ceramics at average and short-scale localized structure. Temperature dependent dielectric properties showed ferroelectric–ergodic relaxor (FE–ER) transition in Nb-modified BNBT–SZ ceramics by producing a significant disruption of the long-range FE order. A giant normalized strain of 825 pm/V at 4 kV/mm was achieved at Nb1.0. Interestingly, at a relatively low applied field of 3 kV/mm, the Nb0.75 sample displayed a large electric field-induced strain (EFIS) response of 0.20%, which is highest value obtained in non-textured lead-free BNT-based ceramics at such low driving field. The structural distortion induced by doping and electric poling is correlated with the dielectric, ferroelectric and EFIS response, and the evolution of giant strain was ascribed to reversible field induced phase transition from ER–FE phase

Structural and electrical properties of Nd ion modified lead zirconate titanate nanopowders and ceramics

International Nuclear Information System (INIS)

Da-Wei, Wang; De-Qing, Zhang; Quan-Liang, Zhao; Hong-Mei, Liu; Zhi-Ying, Wang; Mao-Sheng, Cao; Jie, Yuan

2009-01-01

A modified sol-gel method is used for synthesizing Nd ion doped lead zirconate titanate nanopowders Pb 1–3x/2 Nd x Zr 0.52 Ti 0.48 O 3 (PNZT) in an ethylene glycol system with zirconium nitrate as zirconium source. The results show that it is critical to add lead acetate after the reaction of zirconium nitrate with tetrabutyl titanate in the ethylene glycol system for preparing PNZT with an exact fraction of titanium content. It has been observed that the dopant of excess Nd ions can effectively improve the sintered densification and activity of the PNZT ceramics. Piezoelectric, dielectric and ferroelectric properties of the PNZT ceramics are remarkably enhanced as compared with those of monolithic lead zirconate titanate (PZT). Especially, the supreme values of piezoelectric constant (d 33 ) and dielectric constant ( element of ) for the PNZT are both about two times that of the monolithic PZT and moreover, the remnant polarization (P r ) also increases by 30%. According to the analysis of the structures and properties, we attribute the improvement in electrical properties to the lead vacancies caused by the doping of Nd ions

Mechanical confinement for improved energy storage density in BNT-BT-KNN lead-free ceramic capacitors

Energy Technology Data Exchange (ETDEWEB)

Chauhan, Aditya; Patel, Satyanarayan; Vaish, Rahul, E-mail: rahul@iitmandi.ac.in [School of Engineering, Indian Institute of Technology Mandi, 175 001 (India)

2014-08-15

With the advent of modern power electronics, embedded circuits and non-conventional energy harvesting, the need for high performance capacitors is bound to become indispensible. The current state-of-art employs ferroelectric ceramics and linear dielectrics for solid state capacitance. However, lead-free ferroelectric ceramics propose to offer significant improvement in the field of electrical energy storage owing to their high discharge efficiency and energy storage density. In this regards, the authors have investigated the effects of compressive stress as a means of improving the energy storage density of lead-free ferroelectric ceramics. The energy storage density of 0.91(Bi{sub 0.5}Na{sub 0.5})TiO{sub 3}-0.07BaTiO{sub 3}-0.02(K{sub 0.5}Na{sub 0.5})NbO{sub 3} ferroelectric bulk ceramic was analyzed as a function of varying levels of compressive stress and operational temperature .It was observed that a peak energy density of 387 mJ.cm{sup -3} was obtained at 100 MPa applied stress (25{sup o}C). While a maximum energy density of 568 mJ.cm{sup -3} was obtained for the same stress at 80{sup o}C. These values are indicative of a significant, 25% and 84%, improvement in the value of stored energy compared to an unloaded material. Additionally, material's discharge efficiency has also been discussed as a function of operational parameters. The observed phenomenon has been explained on the basis of field induced structural transition and competitive domain switching theory.

Ultrahigh piezoelectricity in ferroelectric ceramics by design

Science.gov (United States)

Li, Fei; Lin, Dabin; Chen, Zibin; Cheng, Zhenxiang; Wang, Jianli; Li, ChunChun; Xu, Zhuo; Huang, Qianwei; Liao, Xiaozhou; Chen, Long-Qing; Shrout, Thomas R.; Zhang, Shujun

2018-03-01

Piezoelectric materials, which respond mechanically to applied electric field and vice versa, are essential for electromechanical transducers. Previous theoretical analyses have shown that high piezoelectricity in perovskite oxides is associated with a flat thermodynamic energy landscape connecting two or more ferroelectric phases. Here, guided by phenomenological theories and phase-field simulations, we propose an alternative design strategy to commonly used morphotropic phase boundaries to further flatten the energy landscape, by judiciously introducing local structural heterogeneity to manipulate interfacial energies (that is, extra interaction energies, such as electrostatic and elastic energies associated with the interfaces). To validate this, we synthesize rare-earth-doped Pb(Mg1/3Nb2/3)O3-PbTiO3 (PMN-PT), as rare-earth dopants tend to change the local structure of Pb-based perovskite ferroelectrics. We achieve ultrahigh piezoelectric coefficients d33 of up to 1,500 pC N-1 and dielectric permittivity ɛ33/ɛ0 above 13,000 in a Sm-doped PMN-PT ceramic with a Curie temperature of 89 °C. Our research provides a new paradigm for designing material properties through engineering local structural heterogeneity, expected to benefit a wide range of functional materials.

Active Elastic Support/Dry Friction Damper with Piezoelectric Ceramic Actuator

Directory of Open Access Journals (Sweden)

Liao Mingfu

2014-01-01

Full Text Available The basic operation principle of elastic support/dry friction damper in rotor system was introduced and the unbalance response of the rotor with elastic support/dry friction damper was analyzed theoretically. Based on the previous structure using an electromagnet as actuator, an active elastic support/dry friction damper using piezoelectric ceramic actuator was designed and its effectiveness of reducing rotor vibration when rotor traverses its critical speed and blade-out event happened was experimentally verified. The experimental results show that the active elastic support/dry friction damper with piezoelectric ceramic actuator can significantly reduce vibration in rotor system; the vibration amplitude of the rotor in critical speed region decreased more than 2 times, and the active damper can protect the rotor when a blade-out event happened, so the rotor can traverse the critical speed and shut down smoothly. In addition, the structure is much simpler than the previous, the weight was reduced by half and the power consumption was only 5 W.

Lead-Free KNbO3:xZnO Composite Ceramics.

Science.gov (United States)

Lv, Xiang; Li, Zhuoyun; Wu, Jiagang; Xiao, Dingquan; Zhu, Jianguo

2016-11-09

It is a tough issue to develop dense and water resistant KNbO 3 ceramics due to high evaporation and hygroscopicity of K 2 O. Here, KNbO 3 :xZnO composite ceramics were used to successfully solve this problem, where ZnO particles were randomly distributed into a KNbO 3 matrix. The addition of ZnO hardly affects the phase structure of KNbO 3 , and moreover, the enhancement of electrical properties, thermal stability, and aging characteristics was observed in KNbO 3 :xZnO composite ceramics. The composites possessed the maximum d 33 of 120 ± 5 pC/N, which is superior to that of pure KNbO 3 (d 33 = 80 pC/N). More importantly, a strong water resistance and an aging-free characteristic were observed in KNbO 3 :0.4ZnO. This is the first time for KNbO 3 ceramics to simultaneously improve electrical properties and resolve the water-absorbing properties. We believe that these composite ceramics are promising for practical applications.

Effect of MnO doping on the structure, microstructure and electrical properties of the (K,Na,Li)(Nb,Ta,Sb)O3 lead-free piezoceramics

International Nuclear Information System (INIS)

Rubio-Marcos, F.; Marchet, P.; Vendrell, X.; Romero, J.J.; Remondiere, F.; Mestres, L.; Fernandez, J.F.

2011-01-01

Highlights: · MnO doping effects on structure and properties of (K,Na,Li)(Nb,Ta,Sb)O 3 piezoceramics. · The structure changes towards an orthorhombic symmetry for higher MnO concentrations. · High doping levels induce a tetragonal tungsten-bronze secondary phase. · Mn 2+ doping modifies the phase transition temperature and the piezoelectric properties. · Manganese doping increases the mechanical quality factor Q m . - Abstract: Mn 2+ -doped (K,Na,Li)(Nb,Ta,Sb)O 3 lead-free piezoelectric ceramics have been prepared by a conventional sintering technique. The effects of Mn 2+ doping on the phase structure, microstructure and ferro-piezoelectric properties of the ceramics have been evaluated. MnO doping modifies the (K,Na,Li)(Nb,Ta,Sb)O 3 structure, giving rise to the appearance of a TTB-like secondary phase and to changes on the orthorhombic to tetragonal phase transition temperature. The modification of this temperature induces a reduction of the piezoelectric constants, which is accompanied by an increase on the mechanical quality factor. Mn 2+ ions incorporate into the perovskite structure in different off ways depending on their concentration.

High-Power Piezoelectric Vibration Characteristics of Textured SrBi2Nb2O9 Ceramics

Science.gov (United States)

Kawada, Shinichiro; Ogawa, Hirozumi; Kimura, Masahiko; Shiratsuyu, Kosuke; Niimi, Hideaki

2006-09-01

The high-power piezoelectric vibration characteristics of textured SrBi2Nb2O9 (SBN) ceramics, that is bismuth-layer-structured ferroelectrics, were studied in the longitudinal mode (33-mode) by constant current driving method and compared with those of ordinary randomly oriented SBN and widely used Pb(Ti,Zr)O3 (PZT) ceramics. In the case of textured SBN ceramics, resonant properties are stable up to a vibration velocity of 2.6 m/s. Vibration velocity at resonant frequency increases proportionally with the applied electric field, and resonant frequency is almost constant in high-vibration-velocity driving. On the other hand, in the case of randomly oriented SBN and PZT ceramics, the increase in vibration velocity is not proportional to the applied high electric field, and resonant frequency decreases with increasing vibration velocity. The resonant sharpness Q of textured SBN ceramics is about 2000, even at a vibration velocity of 2.6 m/s. Therefore, textured SBN ceramics are good candidates for high-power piezoelectric applications.

Analysis of a rectangular ceramic plate in electrically forced thickness-twist vibration as a piezoelectric transformer.

Science.gov (United States)

Yang, Jiashi; Liu, Jinjin; Li, Jiangyu

2007-04-01

A rectangular ceramic plate with appropriate electrical load and operating mode is analyzed for piezoelectric transformer application. An exact solution from the three-dimensional equations of linear piezoelectricity is obtained. The solution simulates the real operating situation of a transformer as a vibrating piezoelectric body connected to a circuit. Transforming ratio, input admittance, and efficiency of the transformer are obtained.

Dielectric, piezoelectric, and ferroelectric properties of grain-orientated Bi3.25La0.75Ti3O12 ceramics

International Nuclear Information System (INIS)

Liu Jing; Shen Zhijian; Yan Haixue; Reece, Michael J.; Kan Yanmei; Wang Peiling

2007-01-01

By dynamic forging during Spark Plasma Sintering (SPS), grain-orientated ferroelectric Bi 3.25 La 0.75 Ti 3 O 12 (BLT) ceramics were prepared. Their ferroelectric, piezoelectric, and dielectric properties are anisotropic. The textured ceramics parallel and perpendicular to the shear flow directions have similar thermal depoling behaviors. The d 33 piezoelectric coefficient of BLT ceramics gradually reduces up to 350 deg. C; it then drops rapidly. The broadness of the dielectric constant and loss peaks and the existence of d 33 above the permittivity peak, T m , show that the BLT ceramic has relaxor-like behavior

Experiments to Demonstrate Piezoelectric and Pyroelectric Effects

Science.gov (United States)

Erhart, Jirí

2013-01-01

Piezoelectric and pyroelectric materials are used in many current applications. The purpose of this paper is to explain the basic properties of pyroelectric and piezoelectric effects and demonstrate them in simple experiments. Pyroelectricity is presented on lead zirconium titanate (PZT) ceramics as an electric charge generated by the temperature…

Microstructure and electrical properties of (1−x)[0.8Bi_0_._5Na_0_._5TiO_3-0.2Bi_0_._5K_0_._5TiO_3]-xBiCoO_3 lead-free ceramics

International Nuclear Information System (INIS)

Wang, Ting; Chen, Xiao-ming; Qiu, Yan-zi; Lian, Han-li; Chen, Wei-ting

2017-01-01

The (1−x)[0.8Bi_0_._5Na_0_._5TiO_3-0.2Bi_0_._5K_0_._5TiO_3]-xBiCoO_3 (x = 0, 0.02, 0.05, abbreviated as BNKT, BNKT-002Co, BNKT-005Co, respectively) lead-free ferroelectric ceramics were prepared via the solid state reaction method. The phase structure, microstructure, dielectric, ferroelectric, pyroelectric, and piezoelectric properties of the ceramics were investigated comparatively by using a combination of characterization techniques. All the samples exhibit typical X-ray diffraction peaks of ABO_3 perovskite structure. The doping of BiCoO_3 causes a decrease in lattice parameters and an increase in grain size of the ceramics. The Raman spectroscopy results suggest a lattice distortion due to the doping. It is found that BNKT-002Co and BNKT-005Co have higher depolarization temperatures compared with BNKT. The Curie-Weiss law and modified Curie-Weiss law explored a diffuse phase transition character for all the samples. The results of ultraviolet–visible diffuse reflectance suggests that BiCoO_3-doped ceramics possess higher defect concentration. The impedance analysis shows a temperature dependent relaxation behavior, and the activation energy for the electrical responses varies with the change of BiCoO_3 amount. The ferroelectric and piezoelectric properties of the ceramics decrease due to the doping of BiCoO_3. Based on the results of the Rayleigh analysis, it was suggested that the differences in the electrical properties among the ceramics are closely related to the change in oxygen vacancy concentration. - Highlights: • BNKT-xCo ceramics were prepared by solid-state reaction method. • Electrical properties of BNKT ceramics are changed by the doping of BiCoO_3. • The doping causes a decrease in lattice parameters and an increase in grain size. • T_d of the ceramics increases with increasing x. • Oxygen vacancies play key role in determining electrical properties of the ceramics.

Processing, properties, and application of textured 0.72lead(magnesium niobate)-0.28lead titanate ceramics

Science.gov (United States)

Brosnan, Kristen H.

In this study, XRD and electron backscatter diffraction (EBSD) techniques were used to characterize the fiber texture in oriented PMN-28PT and the intensity data were fit with a texture model (the March-Dollase equation) that describes the texture in terms of texture fraction (f), and the width of the orientation distribution (r). EBSD analysis confirmed the orientation of the microstructure, with no distinguishable randomly oriented, fine grain matrix. Although XRD rocking curve and EBSD data analysis gave similar f and r values, XRD rocking curve analysis was the most efficient and gave a complete description of texture fraction and texture orientation (f = 0.81 and r = 0.21, respectively). XRD rocking curve analysis was the preferred approach for characterization of the texture volume and the orientation distribution of texture in fiber-oriented PMN-PT. The dielectric, piezoelectric and electromechanical properties for random ceramic, 69 vol% textured, 81 vol% textured, and single crystal PMN-28PT were fully characterized and compared. The room temperature dielectric constant at 1 kHz for highly textured PMN-28PT was epsilonr ≥ 3600 with low dielectric loss (tan delta = 0.004). The temperature dependence of the dielectric constant for 81 vol% textured ceramic followed a similar trend as the single crystal PMN-28PT up to the rhombohedral to tetragonal transition temperature (TRT) at 104°C. 81 vol% textured PMN-28PT consistently displayed 60 to 65% of the single crystal PMN-28PT piezoelectric coefficient (d33) and 1.5 to 3.0 times greater than the random ceramic d33 (measured by Berlincourt meter, unipolar strain-field curves, IEEE standard resonance method, and laser vibrometry). The 81 vol% textured PMN-28PT displayed similarly low piezoelectric hysteresis as single crystal PMN-28PT measured by strain-field curves at 5 kV/cm. 81 vol% textured PMN-28PT and single crystal PMN-28PT displayed similar mechanical quality factors of QM = 74 and 76, respectively. The

Tuning the electrocaloric enhancement near the morphotropic phase boundary in lead-free ceramics

Science.gov (United States)

Le Goupil, Florian; McKinnon, Ruth; Koval, Vladimir; Viola, Giuseppe; Dunn, Steve; Berenov, Andrey; Yan, Haixue; Alford, Neil Mcn.

2016-06-01

The need for more energy-efficient and environmentally-friendly alternatives in the refrigeration industry to meet global emission targets has driven efforts towards materials with a potential for solid state cooling. Adiabatic depolarisation cooling, based on the electrocaloric effect (ECE), is a significant contender for efficient new solid state refrigeration techniques. Some of the highest ECE performances reported are found in compounds close to the morphotropic phase boundary (MPB). This relationship between performance and the MPB makes the ability to tune the position of the MPB an important challenge in electrocaloric research. Here, we report direct ECE measurements performed on MPB tuned NBT-06BT bulk ceramics with a combination of A-site substitutions. We successfully shift the MPB of these lead-free ceramics closer to room temperature, as required for solid state refrigeration, without loss of the criticality of the system and the associated ECE enhancement.

Quantitative evaluation of the piezoelectric response of unpoled ferroelectric ceramics from elastic and dielectric measurements: Tetragonal BaTiO3

Science.gov (United States)

Cordero, F.

2018-03-01

A method is proposed for evaluating the potential piezoelectric response, that a ferroelectric material would exhibit after full poling, from elastic and dielectric measurements of the unpoled ceramic material. The method is based on the observation that the softening in a ferroelectric phase with respect to the paraelectric phase is of piezoelectric origin, and is tested on BaTiO3. The angular averages of the piezoelectric softening in unpoled ceramics are calculated for ferroelectric phases of different symmetries. The expression of the orientational average with the piezoelectric and dielectric constants of single crystal tetragonal BaTiO3 from the literature reproduces well the softening of the Young's modulus of unpoled ceramic BaTiO3, after a correction for the porosity. The agreement is good in the temperature region sufficiently far from the Curie temperature and from the transition to the orthorhombic phase, where the effect of fluctuations should be negligible, but deviations are found outside this region, and possible reasons for this are discussed. This validates the determination of the piezoelectric response by means of purely elastic measurements on unpoled samples. The method is indirect and, for quantitative assessments, requires the knowledge of the dielectric tensor. On the other hand, it does not require poling of the sample, and therefore is insensitive to inaccuracies from incomplete poling, and can even be used with materials that cannot be poled, for example, due to excessive electrical conductivity. While the proposed example of the Young's modulus of a ceramic provides an orientational average of all the single crystal piezoelectric constants, a Resonant Ultrasound Spectroscopy measurement of a single unpoled ceramic sample through the ferroelectric transition can in principle measure all the piezoelectric constants, together with the elastic ones.

Observation of piezoelectricity in free-standing monolayer MoS₂.

Science.gov (United States)

Zhu, Hanyu; Wang, Yuan; Xiao, Jun; Liu, Ming; Xiong, Shaomin; Wong, Zi Jing; Ye, Ziliang; Ye, Yu; Yin, Xiaobo; Zhang, Xiang

2015-02-01

Piezoelectricity allows precise and robust conversion between electricity and mechanical force, and arises from the broken inversion symmetry in the atomic structure. Reducing the dimensionality of bulk materials has been suggested to enhance piezoelectricity. However, when the thickness of a material approaches a single molecular layer, the large surface energy can cause piezoelectric structures to be thermodynamically unstable. Transition-metal dichalcogenides can retain their atomic structures down to the single-layer limit without lattice reconstruction, even under ambient conditions. Recent calculations have predicted the existence of piezoelectricity in these two-dimensional crystals due to their broken inversion symmetry. Here, we report experimental evidence of piezoelectricity in a free-standing single layer of molybdenum disulphide (MoS₂) and a measured piezoelectric coefficient of e₁₁ = 2.9 × 10(-10) C m(-1). The measurement of the intrinsic piezoelectricity in such free-standing crystals is free from substrate effects such as doping and parasitic charges. We observed a finite and zero piezoelectric response in MoS₂ in odd and even number of layers, respectively, in sharp contrast to bulk piezoelectric materials. This oscillation is due to the breaking and recovery of the inversion symmetry of the two-dimensional crystal. Through the angular dependence of electromechanical coupling, we determined the two-dimensional crystal orientation. The piezoelectricity discovered in this single molecular membrane promises new applications in low-power logic switches for computing and ultrasensitive biological sensors scaled down to a single atomic unit cell.

PLZT-based photovoltaic Piezoelectric Transformer with light feedback

Energy Technology Data Exchange (ETDEWEB)

Kozielski, L [University of Silesia, Dep. Materials Sc, 2, Sniezna St. Sosnowiec, 41-200 Poland (Poland); Adamczyk, M [University of Silesia, Institute Phys., 4, Uniwersytecka St. Katowice, 40-007 Poland (Poland); Erhart, J, E-mail: lucjan.kozielski@us.edu.pl [Technical University of Liberec, Studencka St. 2, CZ-461 17 Liberec (Czech Republic)

2011-10-29

Piezoelectric Transformer (PT) converts an electrical AC input voltage into ultrasonic vibrations and reconverts back to an output as AC voltage. Hard lead zirconate titanate (PZT) ceramics is typically used for fabrications of such devices. In case of lanthaniun ion La{sup 3+} addition in PZT solid solution we can achieve piezoelectric ceramics with good transparency exhibiting both optical Pockels and Kerr effects. Values of these coefficients in the PLZT system are much bigger than in LiNbO{sub 3} or SBN single crystals. Among the various PLZT compositions 8/65/35, near the morphotropic boundary, exhibit large electrooptic effect and thus have found applications in light shutters and displays. In the present study we have investigated radial mode piezoelectric transformer based on optically transparent PLZT8/65/35 ceramics. The effect of the UV light generated photovoltage and photostriction on the efficiency and voltage step-up ratio of piezoelectric transformer have been demonstrated. Novel functions of this device is proposed by superimposing two sophistically coupled effects of piezoelectricity and photostriction.

(Na, K)NbO3-Based Ceramics for Self-Powered Energy Harvesting Applications.

Science.gov (United States)

Kim, Jinhwan; Koh, Jung-Hyuk

2015-03-01

Self-powered energy harvesting technologies have been intensively investigated by employ- ing Pb-free piezoelectric materials. One such Pb-free piezoelectric material, the ceramic 0.97(Na0.5K0.5)NbO3-0.03(Bi0.5Na0.5)TiO3, was prepared by employing the conventional mixed oxide method. 0.97(Na0.5K0.5)NbO3-0.03(Bi0.5Na0.5)TiO3 ceramics were prepared and the effect of sintering temperature on the microstructure, piezoelectric and ferroelectric properties were system- atically investigated for energy harvesting applications. The crystal structure of 0.97(Na0.5K0.5)NbO3- 0.03(Bi0.5Na0.5) TiO3 Pb-free piezoelectric ceramics, sintered at temperatures between 1080 °C and 1160 °C, was examined by X-ray diffraction analysis. The dielectric properties of 0.97(Na0.5K0.5)NbO3-0.03(Bi0.5Na0.5)TiO3 ceramics were measured from 1 kHz to 1 MHz for the various sintering temperatures. We expect that optimization of sintering parameters can improve the piezoelectric and ferroelectric properties of 0.97 (Na0.5K0.5)NbO3-0.03(Bi0.5Na0.5)TiO3 ceramics for energy harvesting.

Piezoelectric properties enhanced of Sr0.6(BiNa)0.2Bi2Nb2O9 ceramic by (LiCe) modification with charge neutrality

International Nuclear Information System (INIS)

Fang, Pinyang; Xi, Zengzhe; Long, Wei; Li, Xiaojuan; Li, Jin

2013-01-01

Graphical abstract: The oxygen vacancies were confirmed by the left figure. The role of oxygen vacancy on piezoelectric activities was obtained by comparing to the varieties of oxygen vacancy concentration and piezoelectric coefficient with (LiCe) modification. -- Highlights: • The Sr 0.6 (BiNa) 0.2 Bi 2 Nb 2 O 9 ceramic by (LiCe) modification with the charge neutrality was synthesized by the solid state reaction method. • The Curie temperature and piezoelectric coefficient were found to be T c ∼590 °C and d 33 ∼32 pC/N, respectively. • The mechanism of piezoelectric activities improved by (LiCe) modification was discussed. -- Abstract: Aurivillius-type ceramics, Sr 0.6−x (LiCe) x/2.5 (BiNa) 0.2 Bi 2 Nb 2 O 9 (SLCBNBNO) with the charge neutrality, were synthesized by using conventional solid-state processing. Phase analysis was performed by X-ray diffraction analyses (XRD) and Raman spectroscopy. Microstructural morphology was assessed by the scanning electron microscopy (SEM). Structural, dielectric, piezoelectric, ferroelectric, and electromechanical properties of the SLCBNBNO ceramics were investigated. Piezoelectric properties were significantly enhanced compared to Sr 0.6 (BiNa) 0.2 Bi 2 Nb 2 O 9 (SBNBN) ceramic and the maximum of piezoelectric coefficient d 33 of the SBNBN-LC6 ceramic was 32 pC/N with higher Curie temperature (T c ∼590 °C). In addition, mechanisms for the piezoelectric properties enhanced of the SBNBN-based ceramics were discussed

PZT/PLZT - elastomer composites with improved piezoelectric voltage coefficient

Science.gov (United States)

Harikrishnan, K.; Bavbande, D. V.; Mohan, Dhirendra; Manoharan, B.; Prasad, M. R. S.; Kalyanakrishnan, G.

2018-02-01

Lead Zirconate Titanate (PZT) and Lanthanum-modified Lead Zirconate Titanate (PLZT) ceramic sensor materials are widely used because of their excellent piezoelectric coefficients. These materials are brittle, high density and have low achievable piezoelectric voltage coefficients. The density of the sintered ceramics shall be reduced by burnable polymeric sponge method. The achievable porosity level in this case is nearly 60 - 90%. However, the porous ceramic structure with 3-3 connectivity produced by this method is very fragile in nature. The strength of the porous structure is improved with Sylgard®-184 (silicone elastomer) by vacuum impregnation method maintaining the dynamic vacuum level in the range of -650 mm Hg. The elastomer Sylgard®-184 is having low density, low dielectric constant and high compliance (as a resultant stiffness of the composites is increased). To obtain a net dipole moment, the impregnated ceramic composites were subjected to poling treatment with varying conditions of D.C. field and temperature. The properties of the poled PZT/PLZT - elastomer composites were characterized with LCR meter for measuring the dielectric constant values (k), d33 meter used for measuring piezo-electric charge coefficient values (d33) and piezo-electric voltage coefficient (g33) values which were derived from d33 values. The voltage coefficient (g33) values of these composites are increased by 10 fold as compared to the conventional solid ceramics demonstrates that it is possible to fabricate a conformable detector.

Effect of the manganese in (Pb1-x Lax) TiO3 piezoelectric ceramics

International Nuclear Information System (INIS)

Garcia, D.; Eiras, J.A.

1990-01-01

Measurements of the relative dielectric constant K, the electric dissipation factor tan δ and the electrochemical coupling factors of the thickness k t and planar K p vibration modes were realized in lead titanate piezoelectric ceramics, with batched composition (Pb 1-3/2x La x )TiO 3 , 0,025 ≤ x ≤0,20. The same parameters were determined in these compositions after the addition of 1%mol of Mn. The results shown clearly that manganese increases the electrochanical anisotropy (K t /K p ) and decreases the dielectric constant and the electric dissipation factor of these materials. (author) [pt

Effect of MnO doping on the structure, microstructure and electrical properties of the (K,Na,Li)(Nb,Ta,Sb)O{sub 3} lead-free piezoceramics

Energy Technology Data Exchange (ETDEWEB)

Rubio-Marcos, F., E-mail: fernando.rubio-marcos@unilim.fr [Laboratoire de Science des Procedes Ceramiques et de Traitements de Surface, UMR 6638 CNRS, Universite de Limoges, Centre Europeen de la Ceramique, 12, rue Atlantis, 87068 Limoges Cedex (France); Marchet, P. [Laboratoire de Science des Procedes Ceramiques et de Traitements de Surface, UMR 6638 CNRS, Universite de Limoges, Centre Europeen de la Ceramique, 12, rue Atlantis, 87068 Limoges Cedex (France); Vendrell, X. [Grup de Quimica de l' Estat Solid, Departament de Quimica Inorganica, Universitat de Barcelona, 08028 Barcelona (Spain); Romero, J.J. [Electroceramic Department, Instituto de Ceramica y Vidrio, CSIC, Kelsen 5, 28049 Madrid (Spain); Remondiere, F. [Laboratoire de Science des Procedes Ceramiques et de Traitements de Surface, UMR 6638 CNRS, Universite de Limoges, Centre Europeen de la Ceramique, 12, rue Atlantis, 87068 Limoges Cedex (France); Mestres, L. [Grup de Quimica de l' Estat Solid, Departament de Quimica Inorganica, Universitat de Barcelona, 08028 Barcelona (Spain); Fernandez, J.F. [Electroceramic Department, Instituto de Ceramica y Vidrio, CSIC, Kelsen 5, 28049 Madrid (Spain)

2011-09-01

Highlights: {center_dot} MnO doping effects on structure and properties of (K,Na,Li)(Nb,Ta,Sb)O{sub 3} piezoceramics. {center_dot} The structure changes towards an orthorhombic symmetry for higher MnO concentrations. {center_dot} High doping levels induce a tetragonal tungsten-bronze secondary phase. {center_dot} Mn{sup 2+} doping modifies the phase transition temperature and the piezoelectric properties. {center_dot} Manganese doping increases the mechanical quality factor Q{sub m}. - Abstract: Mn{sup 2+}-doped (K,Na,Li)(Nb,Ta,Sb)O{sub 3} lead-free piezoelectric ceramics have been prepared by a conventional sintering technique. The effects of Mn{sup 2+} doping on the phase structure, microstructure and ferro-piezoelectric properties of the ceramics have been evaluated. MnO doping modifies the (K,Na,Li)(Nb,Ta,Sb)O{sub 3} structure, giving rise to the appearance of a TTB-like secondary phase and to changes on the orthorhombic to tetragonal phase transition temperature. The modification of this temperature induces a reduction of the piezoelectric constants, which is accompanied by an increase on the mechanical quality factor. Mn{sup 2+} ions incorporate into the perovskite structure in different off ways depending on their concentration.

Label-free detection of endocrine disrupting chemicals by integrating a competitive binding assay with a piezoelectric ceramic resonator.

Science.gov (United States)

Hu, Liang-sheng; Fong, Chi-Chun; Zou, Lan; Wong, Wing-Leung; Wong, Kwok-Yin; Wu, Rudolf S S; Yang, Mengsu

2014-03-15

A piezoelectric biosensor for detection of endocrine disrupting chemicals (EDCs) was developed by incorporating chemical/biochemical recognition elements on the ceramic resonator surface for competitive binding assays. A facile electrodeposition was employed to modify the sensor surface with Au nanoparticles, which increased the surface area and enhanced the binding capacity of the immobilized probes. Thiol-labeled long chain hydrocarbon with bisphenol A (BPA) as head group was synthesized and self-assembled on the Au nanoparticle surface as the sensing probes, which showed a linear response upon the binding of estrogen receptor (ER-α) ranging from 1 to 30 nM. Detection of estrone, 17β-estradiol and BPA was achieved by integrating a competitive binding assay with the piezoelectric sensor. In this detection scheme, different concentrations of EDCs were incubated with 30 nM of ER-α, and the un-bounded ER-α in the solution was captured by the probes immobilized on the ceramic resonator, which resulted in the frequency changes for different EDCs. The biosensor assay exhibited a linear response to EDCs with a low detection limit of 2.4-2.9 nM (S/N=3), and required only a small volume of sample (1.5 µl) with the assay time of 2h. The performance of the biosensor assay was also evaluated for rapid and facile determination of EDCs of environmental relevant concentrations in drinking water and seawater, and the recovery rate was in the range between 94.7% and 109.8%. © 2013 Elsevier B.V. All rights reserved.

Development of a Flexible Lead-Free Piezoelectric Transducer for Health Monitoring in the Space Environment

Directory of Open Access Journals (Sweden)

Marco Laurenti

2015-11-01

Full Text Available In this work we report on the fabrication process for the development of a flexible piezopolymeric transducer for health monitoring applications, based on lead-free, piezoelectric zinc oxide (ZnO thin films. All the selected materials are compatible with the space environment and were deposited by the RF magnetron sputtering technique at room temperature, in view of preserving the total flexibility of the structures, which is an important requirement to guarantee coupling with cylindrical fuel tanks whose integrity we want to monitor. The overall transducer architecture was made of a c-axis-oriented ZnO thin film coupled to a pair of flexible Polyimide foils coated with gold (Au electrodes. The fabrication process started with the deposition of the bottom electrode on Polyimide foils. The ZnO thin film and the top electrode were then deposited onto the Au/Polyimide substrates. Both the electrodes and ZnO layer were properly patterned by wet-chemical etching and optical lithography. The assembly of the final structure was then obtained by gluing the upper and lower Polyimide foils with an epoxy resin capable of guaranteeing low outgassing levels, as well as adequate thermal and electrical insulation of the transducers. The piezoelectric behavior of the prototypes was confirmed and evaluated by measuring the mechanical displacement induced from the application of an external voltage.

Temperature dependence of piezoelectric properties for textured SBN ceramics.

Science.gov (United States)

Kimura, Masahiko; Ogawa, Hirozumi; Kuroda, Daisuke; Sawada, Takuya; Higuchi, Yukio; Takagi, Hiroshi; Sakabe, Yukio

2007-12-01

Temperature dependences of piezoelectric properties were studied for h001i textured ceramics of bismuth layer-structured ferroelectrics, SrBi(2)Nb(2)O(9) (SBN). The textured ceramics with varied orientation degrees were fabricated by templated, grain-growth method, and the temperature dependences of resonance frequency were estimated. Excellent temperature stability of resonance frequency was obtained for the 76% textured ceramics. The resonance frequency of the 76% textured specimens varied almost linearly over a wide temperature range. Therefore, the variation was slight, even in a high temperature region above 150 degrees C. Temperature stability of a quartz crystal oscillator is generally higher than that of a ceramic resonator around room temperature. The variation of resonance frequency for the 76% textured SrBi(2)Nb(2)O(9) was larger than that of oscillation frequency for a typical quartz oscillator below 150 degrees C also in this study. However, the variation of the textured SrBi(2)Nb(2)O(9) was smaller than that of the quartz oscillator over a wide temperature range from -50 to 250 degrees C. Therefore, textured SrBi(2)Nb(2)O(9) ceramics is a major candidate material for the resonators used within a wide temperature range.

Piezo-electrostrictive ceramics

International Nuclear Information System (INIS)

Kim, Ho Gi; Shin, Byeong Cheol

1991-09-01

This book deals with principle and the case of application of piezo-electrostrictive ceramics, which includes definition of piezoelectric materials and production and development of piezoelectric materials, coexistence of Pb(zr, Ti)O 3 ceramics on cause of coexistence in MPB PZT ceramics, electrostrictive effect of oxide type perovskite, practical piezo-electrostrictive materials, and breaking strength, evaluation technique of piezoelectric characteristic, and piezoelectric accelerometer sensor like printer head, ink jet and piezoelectric relay.

Electromechanical properties of engineered lead free potassium sodium niobate based materials =

Science.gov (United States)

Rafiq, Muhammad Asif

K0.5Na0.5NbO3 (KNN), is the most promising lead free material for substituting lead zirconate titanate (PZT) which is still the market leader used for sensors and actuators. To make KNN a real competitor, it is necessary to understand and to improve its properties. This goal is pursued in the present work via different approaches aiming to study KNN intrinsic properties and then to identify appropriate strategies like doping and texturing for designing better KNN materials for an intended application. Hence, polycrystalline KNN ceramics (undoped, non-stoichiometric; NST and doped), high-quality KNN single crystals and textured KNN based ceramics were successfully synthesized and characterized in this work. Polycrystalline undoped, non-stoichiometric (NST) and Mn doped KNN ceramics were prepared by conventional ceramic processing. Structure, microstructure and electrical properties were measured. It was observed that the window for mono-phasic compositions was very narrow for both NST ceramics and Mn doped ceramics. For NST ceramics the variation of A/B ratio influenced the polarization (P-E) hysteresis loop and better piezoelectric and dielectric responses could be found for small stoichiometry deviations (A/B = 0.97). Regarding Mn doping, as compared to undoped KNN which showed leaky polarization (P-E) hysteresis loops, B-site Mn doped ceramics showed a well saturated, less-leaky hysteresis loop and a significant properties improvement. Impedance spectroscopy was used to assess the role of Mn and a relation between charge transport - defects and ferroelectric response in K0.5Na0.5NbO3 (KNN) and Mn doped KNN ceramics could be established. At room temperature the conduction in KNN which is associated with holes transport is suppressed by Mn doping. Hence Mn addition increases the resistivity of the ceramic, which proved to be very helpful for improving the saturation of the P-E loop. At high temperatures the conduction is dominated by the motion of ionized oxygen

Enhanced Piezoelectric Behavior of PVDF Nanocomposite by AC Dielectrophoresis Alignment of ZnO Nanowires

Directory of Open Access Journals (Sweden)

Kyungwho Choi

2017-01-01

Full Text Available In contrast to commercial piezoelectric ceramics, lead-free materials such as ZnO and a polymer matrix are proper candidates for use in ecofriendly applications. In this article, the authors represent a technique using ZnO nanowires with a polyvinylidene fluoride (PVDF matrix in a piezoelectric polymer composite. By aligning the nanowires in the matrix in a desired direction by AC dielectrophoresis, the piezoelectric behavior was enhanced. The dielectric constant of the composite was improved by increasing the concentration of the ZnO nanowires as well. Specifically, the resulting dielectric constant shows an improvement of 400% with aligned ZnO nanowires by increasing the poling effect compared to that of a randomly oriented nanowire composite without a poling process.

Computational and Experimental Insight Into Single-Molecule Piezoelectric Materials

Science.gov (United States)

Marvin, Christopher Wayne

Piezoelectric materials allow for the harvesting of ambient waste energy from the environment. Producing lightweight, highly responsive materials is a challenge for this type of material, requiring polymer, foam, or bio-inspired materials. In this dissertation, I explore the origin of the piezoelectric effect in single molecules through density functional theory (DFT), analyze the piezoresponse of bio-inspired peptidic materials through the use of atomic and piezoresponse force microscopy (AFM and PFM), and develop a novel class of materials combining flexible polyurethane foams and non-piezoelectric, polar dopants. For the DFT calculations, functional group, regiochemical, and heteroatom derivatives of [6]helicene were examined for their influence on the piezoelectric response. An aza[6]helicene derivative was found to have a piezoelectric response (108 pm/V) comparable to ceramics such as lead zirconium titanate (200+ pm/V). These computed materials have the possibility to compete with current field-leading piezomaterials such as lead zirconium titanate (PZT), zinc oxide (ZnO), and polyvinylidene difluoride (PVDF) and its derivatives. The use of AFM/PFM allows for the demonstration of the piezoelectric effect of the selfassembled monolayer (SAM) peptidic systems. Through PFM, the influence that the helicity and sequence of the peptide has on the overall response of the molecule can be analyzed. Finally, development of a novel class of piezoelectrics, the foam-based materials, expands the current understanding of the qualities required for a piezoelectric material from ceramic and rigid materials to more flexible, organic materials. Through the exploration of these novel types of piezoelectric materials, new design rules and figures of merit have been developed.

Disc piezoelectric ceramic transformers.

Science.gov (United States)

Erhart, Jirií; Půlpán, Petr; Doleček, Roman; Psota, Pavel; Lédl, Vít

2013-08-01

In this contribution, we present our study on disc-shaped and homogeneously poled piezoelectric ceramic transformers working in planar-extensional vibration modes. Transformers are designed with electrodes divided into wedge, axisymmetrical ring-dot, moonie, smile, or yin-yang segments. Transformation ratio, efficiency, and input and output impedances were measured for low-power signals. Transformer efficiency and transformation ratio were measured as a function of frequency and impedance load in the secondary circuit. Optimum impedance for the maximum efficiency has been found. Maximum efficiency and no-load transformation ratio can reach almost 100% and 52 for the fundamental resonance of ring-dot transformers and 98% and 67 for the second resonance of 2-segment wedge transformers. Maximum efficiency was reached at optimum impedance, which is in the range from 500 Ω to 10 kΩ, depending on the electrode pattern and size. Fundamental vibration mode and its overtones were further studied using frequency-modulated digital holographic interferometry and by the finite element method. Complementary information has been obtained by the infrared camera visualization of surface temperature profiles at higher driving power.

Using Piezoelectric Ceramics for Dust Mitigation of Space Suits

Science.gov (United States)

Angel, Heather K.

2004-01-01

The particles that make up moon dust and Mars soil can be hazardous to an astronaut s health if not handled properly. In the near future, while exploring outer space, astronauts plan to wander the surfaces of unknown planets. During these explorations, dust and soil will cling to their space suits and become imbedded in the fabric. The astronauts will track moon dust and mars soil back into their living quarters. This not only will create a mess with millions of tiny air-born particles floating around, but will also be dangerous in the case that the fine particles are breathed in and become trapped in an astronaut s lungs. research center are investigating ways to remove these particles from space suits. This problem is very difficult due to the nature of the particles: They are extremely small and have jagged edges which can easily latch onto the fibers of the fabric. For the past summer, I have been involved in researching the potential problems, investigating ways to remove the particles, and conducting experiments to validate the techniques. The current technique under investigation uses piezoelectric ceramics imbedded in the fabric that vibrate and shake the particles free. The particles will be left on the planet s surface or collected a vacuum to be disposed of later. The ceramics vibrate when connected to an AC voltage supply and create a small scale motion similar to what people use at the beach to shake sand off of a beach towel. Because the particles are so small, similar to volcanic ash, caution must be taken to make sure that this technique does not further inbed them in the fabric and make removal more difficult. Only a very precise range of frequency and voltage will produce a suitable vibration. My summer project involved many experiments to determine the correct range. Analysis involved hands on experience with oscilloscopes, amplifiers, piezoelectrics, a high speed camera, microscopes and computers. perfect this technology. Someday, vibration to

The effects of porosity, electrode and barrier materials on the conductivity of piezoelectric ceramics in high humidity and dc electric field

International Nuclear Information System (INIS)

Weaver, P M; Cain, M G; Stewart, M; Anson, A; Franks, J; Lipscomb, I P; McBride, J W; Zheng, D; Swingler, J

2012-01-01

Prolonged operation of piezoelectric ceramic devices under high dc electric fields promotes leakage currents between the electrodes. This paper investigates the effects of ceramic porosity, edge conduction and electrode materials and geometry in the development of low resistance conduction paths through the ceramic. Localized changes in the ceramic structure and corresponding microscopic breakdown sites are shown to be associated with leakage currents and breakdown processes resulting from prolonged operation in harsh environments. The role of barrier coatings in mitigating the effects of humidity is studied, and results are presented on improved performance using composite diamond-like carbon/polymer coatings. In contrast to the changes in the electrical properties of the ceramic, the measurements of the piezoelectric properties showed no significant effect of humidity. (paper)

Strong piezoelectric anisotropy d15/d33 in ⟨111⟩ textured Pb(Mg1/3Nb2/3)O3-Pb(Zr,Ti)O3 ceramics

Science.gov (United States)

Yan, Yongke; Priya, Shashank

2015-08-01

The shear mode piezoelectric properties of Pb(Mg1/3Nb2/3)O3-Pb(Zr,Ti)O3 (PMN-PZT) ceramic with 72% ⟨111⟩ texture were investigated. The piezoelectric anisotropic factor d15/d33 was as high as 8.5 in ⟨111⟩ textured ceramic as compared to 2.0 in random counterpart. The high d15/d33 indicates the "rotator" ferroelectric characteristics of PMN-PZT system and suggests that the large shear piezoelectric response contributes towards the high longitudinal piezoelectric response (d33) in non-polar direction (d33 = 1100 pC/N in ⟨001⟩ textured ceramic vs. d33 = 112 pC/N in ⟨111⟩ textured ceramic).

Effect of texturing on polarization switching dynamics in ferroelectric ceramics

Science.gov (United States)

Zhukov, Sergey; Genenko, Yuri A.; Koruza, Jurij; Schultheiß, Jan; von Seggern, Heinz; Sakamoto, Wataru; Ichikawa, Hiroki; Murata, Tatsuro; Hayashi, Koichiro; Yogo, Toshinobu

2016-01-01

Highly (100),(001)-oriented (Ba0.85Ca0.15)TiO3 (BCT) lead-free piezoelectric ceramics were fabricated by the reactive templated grain growth method using a mixture of plate-like CaTiO3 and BaTiO3 particles. Piezoelectric properties of the ceramics with a high degree of texture were found to be considerably enhanced compared with the BCT ceramics with a low degree of texture. With increasing the Lotgering factor from 26% up to 94%, the piezoelectric properties develop towards the properties of a single crystal. The dynamics of polarization switching was studied over a broad time domain of 8 orders of magnitude and was found to strongly depend on the degree of orientation of the ceramics. Samples with a high degree of texture exhibited 2-3 orders of magnitude faster polarization switching, as compared with the ones with a low degree of texture. This was rationalized by means of the Inhomogeneous Field Mechanism model as a result of the narrower statistical distribution of the local electric field values in textured media, which promotes a more coherent switching process. The extracted microscopic parameters of switching revealed a decrease of the critical nucleus energy in systems with a high degree of texture providing more favorable switching conditions related to the enhanced ferroelectric properties of the textured material.

Microstructure and electrical properties of (1−x)[0.8Bi{sub 0.5}Na{sub 0.5}TiO{sub 3}-0.2Bi{sub 0.5}K{sub 0.5}TiO{sub 3}]-xBiCoO{sub 3} lead-free ceramics

Energy Technology Data Exchange (ETDEWEB)

Wang, Ting [School of Physics and Information Technology, Shaanxi Normal University, Xi’an, 710119 (China); Chen, Xiao-ming, E-mail: xmchen@snnu.edu.cn [School of Physics and Information Technology, Shaanxi Normal University, Xi’an, 710119 (China); Qiu, Yan-zi [School of Physics and Information Technology, Shaanxi Normal University, Xi’an, 710119 (China); Lian, Han-li [School of Science, Xi’an University of Posts and Telecommunications, Xi’an, 710121 (China); Chen, Wei-ting [Department of Electrical Engineering, National Cheng Kung University, Tainan City, 701, Taiwan (China)

2017-01-15

The (1−x)[0.8Bi{sub 0.5}Na{sub 0.5}TiO{sub 3}-0.2Bi{sub 0.5}K{sub 0.5}TiO{sub 3}]-xBiCoO{sub 3} (x = 0, 0.02, 0.05, abbreviated as BNKT, BNKT-002Co, BNKT-005Co, respectively) lead-free ferroelectric ceramics were prepared via the solid state reaction method. The phase structure, microstructure, dielectric, ferroelectric, pyroelectric, and piezoelectric properties of the ceramics were investigated comparatively by using a combination of characterization techniques. All the samples exhibit typical X-ray diffraction peaks of ABO{sub 3} perovskite structure. The doping of BiCoO{sub 3} causes a decrease in lattice parameters and an increase in grain size of the ceramics. The Raman spectroscopy results suggest a lattice distortion due to the doping. It is found that BNKT-002Co and BNKT-005Co have higher depolarization temperatures compared with BNKT. The Curie-Weiss law and modified Curie-Weiss law explored a diffuse phase transition character for all the samples. The results of ultraviolet–visible diffuse reflectance suggests that BiCoO{sub 3}-doped ceramics possess higher defect concentration. The impedance analysis shows a temperature dependent relaxation behavior, and the activation energy for the electrical responses varies with the change of BiCoO{sub 3} amount. The ferroelectric and piezoelectric properties of the ceramics decrease due to the doping of BiCoO{sub 3}. Based on the results of the Rayleigh analysis, it was suggested that the differences in the electrical properties among the ceramics are closely related to the change in oxygen vacancy concentration. - Highlights: • BNKT-xCo ceramics were prepared by solid-state reaction method. • Electrical properties of BNKT ceramics are changed by the doping of BiCoO{sub 3}. • The doping causes a decrease in lattice parameters and an increase in grain size. • T{sub d} of the ceramics increases with increasing x. • Oxygen vacancies play key role in determining electrical properties of the ceramics.

Stable Ferroelectric Behavior of Nb-Modified Bi0.5K0.5TiO3-Bi(Mg0.5Ti0.5)O3 Lead-Free Relaxor Ferroelectric Ceramics

Science.gov (United States)

Zaman, Arif; Malik, Rizwan Ahmed; Maqbool, Adnan; Hussain, Ali; Ahmed, Tanveer; Song, Tae Kwon; Kim, Won-Jeong; Kim, Myong-Ho

2018-03-01

Crystal structure, dielectric, ferroelectric, piezoelectric, and electric field-induced strain properties of lead-free Nb-modified 0.96Bi0.5K0.5TiO3-0.04Bi(Mg0.5Ti0.5)O3 (BKT-BMT) piezoelectric ceramics were investigated. Crystal structure analysis showed a gradual phase transition from tetragonal to pseudocubic phase with increasing Nb content. The optimal piezoelectric property of small-signal d 33 was enhanced up to ˜ 68 pC/N with a lower coercive field ( E c) of ˜ 22 kV/cm and an improved remnant polarization ( P r) of ˜ 13 μC/cm2 for x = 0.020. A relaxor-like behavior with a frequency-dependent Curie temperature T m was observed, and a high T m around 320°C was obtained in the investigated system. This study suggests that the ferroelectric properties of BKT-BMT was significantly improved by means of Nb substitution. The possible shift of depolarization temperature T d toward high temperature T m may have triggered the spontaneous relaxor to ferroelectric phase transition with long-range ferroelectric order without any traces of a nonergodic relaxor state in contradiction with Bi0.5Na0.5TiO3-based systems. The possible enhancement in ferroelectric and piezoelectric properties near the critical composition x = 0.020 may be attributed to the increased anharmonicity of lattice vibrations which may facilitate the observed phase transition from a low-symmetry tetragonal to a high-symmetry cubic phase with a decrease in the lattice anisotropy of an undoped sample. This highly flexible (at a unit cell level) narrow compositional range triggers the enhancement of d 33 and P r values.

Electronic property measurements for piezoelectric ceramics. Technical notes

International Nuclear Information System (INIS)

Cain, M.; Stewart, M.; Gee, M.

1998-01-01

A series of measurement notes are presented, with emphasis placed on the technical nature of the testing methodology, for the determination of key electronic properties for piezoelectric ceramic materials that are used as sensors and actuators. The report is segmented into 'sections' that may be read independently from the rest of the report. The following measurement issues are discussed: Polarisation/Electric field (PE) loop measurements including a discussion of commercial and an in-house constructed system that measures PE loops; Dielectric measurements at low and high stress application, including some thermal and stress dependency modelling of piezo materials properties, developed at NPL; Strain measurement techniques developed at CMMT; Charge measurement techniques suitable for PE loop and other data acquisition; PE loop measurement and software analysis developed at CMMT and Manchester University. The primary objective of this report is to provide a framework on which the remainder of the testing procedures are to be developed for measurements of piezoelectric properties at high stress and stress rate. These procedures will be the subject of a future publication. (author)

Nonlinear free vibration of piezoelectric nanobeams incorporating surface effects

International Nuclear Information System (INIS)

Hosseini-Hashemi, Shahrokh; Nahas, Iman; Fakher, Mahmood; Nazemnezhad, Reza

2014-01-01

In this study, the nonlinear free vibration of piezoelectric nanobeams incorporating surface effects (surface elasticity, surface tension, and surface density) is studied. The governing equation of the piezoelectric nanobeam is derived within the framework of Euler–Bernoulli beam theory with the von Kármán geometric nonlinearity. In order to satisfy the balance conditions between the nanobeam bulk and its surfaces, the component of the bulk stress, σ zz , is assumed to vary linearly through the nanobeam thickness. An exact solution is obtained for the natural frequencies of a simply supported piezoelectric nanobeam in terms of the Jacobi elliptic functions using the free vibration mode shape of the corresponding linear problem. Then, the influences of the surface effects and the piezoelectric field on the nonlinear free vibration of nanobeams made of aluminum and silicon with positive and negative surface elasticity, respectively, have been studied for various properties of the piezoelectric field, various nanobeam sizes and amplitude ratios. It is observed that if the Young’s modulus of a nanobeam is lower, the effect of the piezoelectric field on the frequency ratios (FRs) of the nanobeam will be greater. In addition, it is seen that by increasing the nanobeam length so that the nanobeam cross section is set to be constant, the surface effects and the piezoelectric field with negative voltage values increases the FRs, whereas it is the other way around when the nanobeam cross section is assumed to be dependent on the length of the nanobeam. (paper)

Study of the microstructure and the hardness of PZT piezoelectric ceramics types I and III used in electro acoustic transducers; Estudo da microestrutura e da microdureza das ceramicas piezoeletricas tipos PZT I e III utilizadas em transdutores eletroacusticos

Energy Technology Data Exchange (ETDEWEB)

Cabral, Ricardo de Freitas; Itaboray, Lucas Mendes; Santos, Anna Paula de Oliveira [Centro Universitario de Volta Redonda (UNIFOA), Volta Redonda, RJ (Brazil)

2015-12-15

The field of electronic processing of the ceramic piezoelectric type imported powdered led to the production of ceramics with 97% of theoretical density, homogeneous microstructure with great potential for applications in piezoelectric devices such as electro acoustic transducers. However, the production of electronic ceramics National piezoelectric type is not yet able to have as raw material zirconate titanate Lead (PZT) 100% made in Brazil. Thus, this is used for supply of domestic production, the zirconium oxide. In this work, both post PZT types I and III, imported, were uniaxially pressed at 70 MPa and sintered at 1200 and 1250 deg C for 3 hours. Hardness measurements were performed by micro indentation, X-ray diffraction analysis and Scanning Electron Microscopy. The hardness of PZT I was 393 HV. (author)

Displacive Transformation in Ceramics

Science.gov (United States)

1994-02-28

PZT ), ceramics have attracted natural abundance. much attention for use in nonvolatile semiconductor mem- We attribute the observed spectra in Fig. I to...near a crack tip in piezoelectric ceramics of lead zirconate titanate ( PZT ) and barium titanate. They reasoned that the poling of ferroelectric... Texture in Ferroelastic Tetragonal Zirconia," J. Am. Ceram . Soc., 73 (1990) no. 6: 1777-1779. 27. J. F. Jue and A. Virkar, "Fabrication, Microstructural

Enhanced Energy-Storage Density and High Efficiency of Lead-Free CaTiO3-BiScO3 Linear Dielectric Ceramics.

Science.gov (United States)

Luo, Bingcheng; Wang, Xiaohui; Tian, Enke; Song, Hongzhou; Wang, Hongxian; Li, Longtu

2017-06-14

A novel lead-free (1 - x)CaTiO 3 -xBiScO 3 linear dielectric ceramic with enhanced energy-storage density was fabricated. With the composition of BiScO 3 increasing, the dielectric constant of (1 - x)CaTiO 3 -xBiScO 3 ceramics first increased and then decreased after the composition x > 0.1, while the dielectric loss decreased first and increased. For the composition x = 0.1, the polarization was increased into 12.36 μC/cm 2 , 4.6 times higher than that of the pure CaTiO 3 . The energy density of 0.9CaTiO 3 -0.1BiScO 3 ceramic was 1.55 J/cm 3 with the energy-storage efficiency of 90.4% at the breakdown strength of 270 kV/cm, and the power density was 1.79 MW/cm 3 . Comparison with other lead-free dielectric ceramics confirmed the superior potential of CaTiO 3 -BiScO 3 ceramics for the design of ceramics capacitors for energy-storage applications. First-principles calculations revealed that Sc subsitution of Ti-site induced the atomic displacement of Ti ions in the whole crystal lattice, and lattice expansion was caused by variation of the bond angles and lenghths. Strong hybridization between O 2p and Ti 3d was observed in both valence band and conduction band; the hybridization between O 2p and Sc 3d at high conduction band was found to enlarge the band gap, and the static dielectric tensors were increased, which was the essential for the enhancement of polarization and dielectric properties.

Structured Piezoelectric Composites: Materials and Applications

OpenAIRE

Van den Ende, D.A.

2012-01-01

The piezoelectric effect, which causes a material to generate a voltage when it deforms, is very suitable for making integrated sensors, and (micro-) generators. However, conventional piezoelectric materials are either brittle ceramics or certain polymers with a low thermal stability, which limits their practical application to certain specific fields. Piezoelectric composites, which contain an active piezoelectric (ceramic) phase in a robust polymer matrix, can potentially have better proper...

Influences of donor dopants on the properties of PZT-PMS-PZN piezoelectric ceramics sintered at low temperatures

International Nuclear Information System (INIS)

Yoon, Seokjin; Choi, Jiwon; Choi, Jooyoung; Wan, Dandan; Li, Qian; Yang, Ying

2010-01-01

0.90Pb(Zr 0.48 Ti 0.52 )O 3 -0.05Pb(Mn 1/3 Sb 2/3 )O 3 -0.05Pb(Zn 1/3 Nb 2/3 )O 3 quaternary piezoelectric ceramics with CuO added were synthesized by using a conventional method at low sintering temperatures. CuO additive, 1.0 wt%, significantly improves the sinterability of 0.90PZT-0.05PMS-0.05PZN ceramics, lowering the sintering temperature to 900 .deg. C and showing moderate electrical properties: d 33 = 306 pC/N, Q m = 997, k p = 53.6%, tanδ = 0.50%, and ε T 33 = 1351. To obtain more optimal piezoelectric properties, we selected Bi 2 O 3 and Nb 2 O 5 as donor dopants to introduce a softening effect. The crystal structure, micro-morphology and electrical properties were studied in terms of the Bi 2 O 3 and the Nb 2 O 5 contents. Our study demonstrates that Bi 2 O 3 is very effective in improving the piezoelectric properties, causing a significant enhancement in d 33 and k p values. Particularly, 0.75-wt%-Bi 2 O 3 -added 0.90PZT-0.05PMS-0.05PZN + 1.0 wt% CuO ceramics show excellent electrical properties: d 33 = 363 pC/N, Q m = 851, k p = 59.3%, tanδ = 0.38%, and ε T 33 = 1596. On the other hand, the effect of Nb 2 O 5 on the piezoelectric properties is very complicated, 0.50 wt% Nb 2 O 5 doped 0.90PZT-0.05PMS-0.05PZN + 1.0 wt% CuO ceramics have a remarkable improvement in k p value and maintain good electrical properties: d 33 = 300 pC/N, Q m = 971, k p = 58.4%, tanδ = 0.36%, and ε T 33 = 1332.

Unique Piezoelectric Properties of the Monoclinic Phase in Pb (Zr ,Ti )O3 Ceramics: Large Lattice Strain and Negligible Domain Switching

Science.gov (United States)

Fan, Longlong; Chen, Jun; Ren, Yang; Pan, Zhao; Zhang, Linxing; Xing, Xianran

2016-01-01

The origin of the excellent piezoelectric properties at the morphotropic phase boundary is generally attributed to the existence of a monoclinic phase in various piezoelectric systems. However, there exist no experimental studies that reveal the role of the monoclinic phase in the piezoelectric behavior in phase-pure ceramics. In this work, a single monoclinic phase has been identified in Pb (Zr ,Ti )O3 ceramics at room temperature by in situ high-energy synchrotron x-ray diffraction, and its response to electric field has been characterized for the first time. Unique piezoelectric properties of the monoclinic phase in terms of large intrinsic lattice strain and negligible domain switching have been observed. The extensional strain constant d33 and the transverse strain constant d31 are calculated to be 520 and -200 pm /V , respectively. These large piezoelectric coefficients are mainly due to the large intrinsic lattice strain, with very little extrinsic contribution from domain switching. The unique properties of the monoclinic phase provide new insights into the mechanisms responsible for the piezoelectric properties at the morphotropic phase boundary.

Unique Piezoelectric Properties of the Monoclinic Phase in Pb(Zr,Ti)O_{3} Ceramics: Large Lattice Strain and Negligible Domain Switching.

Science.gov (United States)

Fan, Longlong; Chen, Jun; Ren, Yang; Pan, Zhao; Zhang, Linxing; Xing, Xianran

2016-01-15

The origin of the excellent piezoelectric properties at the morphotropic phase boundary is generally attributed to the existence of a monoclinic phase in various piezoelectric systems. However, there exist no experimental studies that reveal the role of the monoclinic phase in the piezoelectric behavior in phase-pure ceramics. In this work, a single monoclinic phase has been identified in Pb(Zr,Ti)O_{3} ceramics at room temperature by in situ high-energy synchrotron x-ray diffraction, and its response to electric field has been characterized for the first time. Unique piezoelectric properties of the monoclinic phase in terms of large intrinsic lattice strain and negligible domain switching have been observed. The extensional strain constant d_{33} and the transverse strain constant d_{31} are calculated to be 520 and -200  pm/V, respectively. These large piezoelectric coefficients are mainly due to the large intrinsic lattice strain, with very little extrinsic contribution from domain switching. The unique properties of the monoclinic phase provide new insights into the mechanisms responsible for the piezoelectric properties at the morphotropic phase boundary.

Evaluation of electromechanical coupling parameters of piezoelectric materials by using piezoelectric cantilever with coplanar electrode structure in quasi-stasis.

Science.gov (United States)

Zheng, Xuejun; Zhu, Yuankun; Liu, Xun; Liu, Jing; Zhang, Yong; Chen, Jianguo

2014-02-01

Based on Timoshenko beam theory, a principle model is proposed to establish the relationship between electric charge and excitation acceleration, and in quasi-stasis we apply the direct piezoelectric effect of multilayer cantilever with coplanar electrode structure to evaluate the piezoelectric strain coefficient d15 and electromechanical coupling coefficient k15. They are measured as 678 pC/N and 0.74 for the commercial piezoelectric ceramic lead zirconate titanate (PZT-51) bulk specimen and 656 pC/N and 0.63 for the lead magnesium niobate (PMN) bulk specimen, and they are in agreement with the calibration and simulation values. The maximum of relative errors is less than 4.2%, so the proposed method is reliable and convenient.

Piezoelectric properties and thermal stability of (Na0.53K0.47-xAgx)Nb1-xSbxO3 ceramics

International Nuclear Information System (INIS)

Zheng, Limei; Wang, Jinfeng; Wang, Chunming; Gai, Zhigang; Wu, Qingzao; Zhang, Rui

2011-01-01

Many (K 1-x Na x )NbO 3 (KNN)-based ceramics with high piezoelectric performance exhibit undesirable strong temperature dependence due to the orthorhombic-tetragonal polymorphic phase transition near room temperature. In order to improve the temperature stability of the ceramics, many additives have been added into the KNN-based ceramics to shift T O-T down to below room temperature. Contrary to the previous approach (Na 0.53 K 0.47-x Ag x )Nb 1-x Sb x O 3 (NKANS) ceramics with T O-T well above room temperature have been prepared by a conventional solid-state reaction method. The density and the electrical properties are effectively improved by the addition of AgSbO 3 , and optimum piezoelectric properties are found in the ceramics with 0.05 ≤ x ≤ 0.07, with maximum k p ∝ 0.46 for NKANS5 and maximum d 33 ∝ 199 pC/N for NKANS7. More importantly, k p remains virtually almost unchanged up to the T O-T temperature (≥100 C), indicating that the NKANS ceramics exhibit a much improved piezoelectric thermal stability. The analyses suggest that both the high T O-T value and diffuse orthorhombic-tetragonal phase transition should be responsible for the good temperature stability. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Electronically droplet energy harvesting using piezoelectric cantilevers

KAUST Repository

Al Ahmad, Mahmoud Al; Jabbour, Ghassan E.

2012-01-01

A report is presented on free falling droplet energy harvesting using piezoelectric cantilevers. The harvester incorporates a multimorph clamped-free cantilever which is composed of five layers of lead zirconate titanate piezoelectric thick films

Temperature coefficient of piezoelectric constants in Pb(Mg1/3 Nb2/3O3 - PbTiO3 ceramics

Directory of Open Access Journals (Sweden)

Manuel Henrique Lente

2004-06-01

Full Text Available In this work, the thermal stability of piezoelectric constants of PMN-PT ceramics in the tetragonal and rhombohedral phases were investigated in a wide range of temperatures. The results showed that the tetragonal PMN-PT presented higher thermal stability and, consequently, the temperature coefficients for the piezoelectric constants were approximately zero. This result revealed to be much better than that commonly found for PZT ceramics. Although the rhombohedral PMN-PT presented a slight lower thermal stability, the values found for the coupling factor were significantly higher than the tetragonal composition.

Design and Development for Capacitive Humidity Sensor Applications of Lead-Free Ca,Mg,Fe,Ti-Oxides-Based Electro-Ceramics with Improved Sensing Properties via Physisorption

Science.gov (United States)

Tripathy, Ashis; Pramanik, Sumit; Manna, Ayan; Bhuyan, Satyanarayan; Azrin Shah, Nabila Farhana; Radzi, Zamri; Abu Osman, Noor Azuan

2016-01-01

Despite the many attractive potential uses of ceramic materials as humidity sensors, some unavoidable drawbacks, including toxicity, poor biocompatibility, long response and recovery times, low sensitivity and high hysteresis have stymied the use of these materials in advanced applications. Therefore, in present investigation, we developed a capacitive humidity sensor using lead-free Ca,Mg,Fe,Ti-Oxide (CMFTO)-based electro-ceramics with perovskite structures synthesized by solid-state step-sintering. This technique helps maintain the submicron size porous morphology of the developed lead-free CMFTO electro-ceramics while providing enhanced water physisorption behaviour. In comparison with conventional capacitive humidity sensors, the presented CMFTO-based humidity sensor shows a high sensitivity of up to 3000% compared to other materials, even at lower signal frequency. The best also shows a rapid response (14.5 s) and recovery (34.27 s), and very low hysteresis (3.2%) in a 33%–95% relative humidity range which are much lower values than those of existing conventional sensors. Therefore, CMFTO nano-electro-ceramics appear to be very promising materials for fabricating high-performance capacitive humidity sensors. PMID:27455263

Piezoelectric effect in polarized and electrically depolarized ferrotextures

International Nuclear Information System (INIS)

Luchaninov, A.G.; Shil'nikov, A.V.; Shuvalov, L.A.

1999-01-01

Piezoelectric moduli were calculated for ferroelectric textures in the states with the greatest possible (in terms of symmetry) polarization and the zero polarization (obtained from the former by electrical depolarization). The calculations were performed for the textures of crystals of the classes 2, 3, 4, 6, mm2, 3m, 4mm,and 6mm. The experimental results for lead zirconate-titanate- and barium-titanate-based piezoelectric ceramic are reported

Development of piezoelectric composites for transducers

Science.gov (United States)

Safari, A.

1994-07-01

For the past decade and a half, many different types of piezoelectric ceramic-polymer composites have been developed intended for transducer applications. These diphasic composites are prepared from non-active polymer, such as epoxy, and piezoelectric ceramic, such as PZT, in the form of filler powders, elongated fibers, multilayer and more complex three-dimensional structures. For the last four years, most of the efforts have been given to producing large area and fine scale PZT fiber composites. In this paper, processing of piezoelectric ceramic-polymer composites with various connectivity patterns are reviewed. Development of fine scale piezoelectric composites by lost mold, injection molding and the relic method are described. Research activities of different groups for preparing large area piezocomposites for hydrophone and actuator applications are briefly reviewed. Initial development of electrostrictive ceramics and composites are also

Bar piezoelectric ceramic transformers.

Science.gov (United States)

Erhart, Jiří; Pulpan, Půlpán; Rusin, Luboš

2013-07-01

Bar-shaped piezoelectric ceramic transformers (PTs) working in the longitudinal vibration mode (k31 mode) were studied. Two types of the transformer were designed--one with the electrode divided into two segments of different length, and one with the electrodes divided into three symmetrical segments. Parameters of studied transformers such as efficiency, transformation ratio, and input and output impedances were measured. An analytical model was developed for PT parameter calculation for both two- and three-segment PTs. Neither type of bar PT exhibited very high efficiency (maximum 72% for three-segment PT design) at a relatively high transformation ratio (it is 4 for two-segment PT and 2 for three-segment PT at the fundamental resonance mode). The optimum resistive loads were 20 and 10 kΩ for two- and three-segment PT designs for the fundamental resonance, respectively, and about one order of magnitude smaller for the higher overtone (i.e., 2 kΩ and 500 Ω, respectively). The no-load transformation ratio was less than 27 (maximum for two-segment electrode PT design). The optimum input electrode aspect ratios (0.48 for three-segment PT and 0.63 for two-segment PT) were calculated numerically under no-load conditions.

Three-degree-of-freedom ultrasonic motor using a 5-mm-diameter piezoelectric ceramic tube.

Science.gov (United States)

Mingsen Guo; Junhui Hu; Hua Zhu; Chunsheng Zhao; Shuxiang Dong

2013-07-01

A small three-degree-of-freedom ultrasonic motor has been developed using a simple piezoelectric lead zirconate titanate (PZT)-tube stator (OD 5 mm, ID 3 mm, length 15 mm). The stator drives a ball-rotor into rotational motion around one of three orthogonal (x-, y-, and z-) axes by combing the first longitudinal and second bending vibration modes. A motor prototype was fabricated and characterized; its performance was superior to those of previous motors made with a PZT ceramic/metal composite stator of comparable size. The method for further improving the performance was discussed. The motor can be further miniaturized and it has potential to be applied to medical microrobots, endoscopes or micro laparoscopic devices, and cell manipulation devices.

Effect of orthorhombic distortion on dielectric and piezoelectric properties of CaBi4Ti4O15 ceramics

Science.gov (United States)

Tanwar, Amit; Sreenivas, K.; Gupta, Vinay

2009-04-01

High temperature bismuth layered piezoelectric and ferroelectric ceramics of CaBi4Ti4O15 (CBT) have been prepared using the solid state route. The formation of single phase material with orthorhombic structure was verified from x-ray diffraction and Raman spectroscopy. The orthorhombic distortion present in the CBT ceramic sintered at 1200 °C was found to be maximum. A sharp phase transition from ferroelectric to paraelectric was observed in the temperature dependent dielectric studies of all CBT ceramics. The Curie's temperature (Tc=790 °C) was found to be independent of measured frequency. The behavior of ac conductivity as a function of frequency (100 Hz-1 MHz) at low temperatures (<500 °C) follows the power law and is attributed to hopping conduction. The presence of large orthorhombic distortion in the CBT ceramic sintered at 1200 °C results in high dielectric constant, low dielectric loss, and high piezoelectric coefficient (d33). The observed results indicate the important role of orthorhombic distortion in determining the improved property of multicomponent ferroelectric material.

Magnetoelectric Interactions in Lead-Based and Lead-Free Composites.

Science.gov (United States)

Bichurin, Mirza; Petrov, Vladimir; Zakharov, Anatoly; Kovalenko, Denis; Yang, Su Chul; Maurya, Deepam; Bedekar, Vishwas; Priya, Shashank

2011-04-06

Magnetoelectric (ME) composites that simultaneously exhibit ferroelectricity and ferromagnetism have recently gained significant attention as evident by the increasing number of publications. These research activities are direct results of the fact that multiferroic magnetoelectrics offer significant technological promise for multiple devices. Appropriate choice of phases with co-firing capability, magnetostriction and piezoelectric coefficient, such as Ni-PZT and NZFO-PZT, has resulted in fabrication of prototype components that promise transition. In this manuscript, we report the properties of Ni-PZT and NZFO-PZT composites in terms of ME voltage coefficients as a function of frequency and magnetic DC bias. In order to overcome the problem of toxicity of lead, we have conducted experiments with Pb-free piezoelectric compositions. Results are presented on the magnetoelectric performance of Ni-NKN, Ni-NBTBT and NZFO-NKN, NZFO-NBTBT systems illustrating their importance as an environmentally friendly alternative.

Magnetoelectric Interactions in Lead-Based and Lead-Free Composites

Directory of Open Access Journals (Sweden)

Shashank Priya

2011-04-01

Full Text Available Magnetoelectric (ME composites that simultaneously exhibit ferroelectricity and ferromagnetism have recently gained significant attention as evident by the increasing number of publications. These research activities are direct results of the fact that multiferroic magnetoelectrics offer significant technological promise for multiple devices. Appropriate choice of phases with co-firing capability, magnetostriction and piezoelectric coefficient, such as Ni-PZT and NZFO-PZT, has resulted in fabrication of prototype components that promise transition. In this manuscript, we report the properties of Ni-PZT and NZFO-PZT composites in terms of ME voltage coefficients as a function of frequency and magnetic DC bias. In order to overcome the problem of toxicity of lead, we have conducted experiments with Pb-free piezoelectric compositions. Results are presented on the magnetoelectric performance of Ni-NKN, Ni-NBTBT and NZFO-NKN, NZFO-NBTBT systems illustrating their importance as an environmentally friendly alternative.

Piezoelectric properties enhanced of Sr{sub 0.6}(BiNa){sub 0.2}Bi{sub 2}Nb{sub 2}O{sub 9} ceramic by (LiCe) modification with charge neutrality

Energy Technology Data Exchange (ETDEWEB)

Fang, Pinyang, E-mail: fpy_2000@163.com [Shaanxi Key Laboratory of Photoelectric Functional Materials and Devices, School of Materials and Chemical Engineering, Xi’an Technological University, Xi’an 710032 (China); Xi, Zengzhe; Long, Wei; Li, Xiaojuan [Shaanxi Key Laboratory of Photoelectric Functional Materials and Devices, School of Materials and Chemical Engineering, Xi’an Technological University, Xi’an 710032 (China); Li, Jin [Northwest Institute For Non-ferrous Metal Research, Xi’an 710016 (China)

2013-09-01

Graphical abstract: The oxygen vacancies were confirmed by the left figure. The role of oxygen vacancy on piezoelectric activities was obtained by comparing to the varieties of oxygen vacancy concentration and piezoelectric coefficient with (LiCe) modification. -- Highlights: • The Sr{sub 0.6}(BiNa){sub 0.2}Bi{sub 2}Nb{sub 2}O{sub 9} ceramic by (LiCe) modification with the charge neutrality was synthesized by the solid state reaction method. • The Curie temperature and piezoelectric coefficient were found to be T{sub c} ∼590 °C and d{sub 33} ∼32 pC/N, respectively. • The mechanism of piezoelectric activities improved by (LiCe) modification was discussed. -- Abstract: Aurivillius-type ceramics, Sr{sub 0.6−x}(LiCe){sub x/2.5}(BiNa){sub 0.2}Bi{sub 2}Nb{sub 2}O{sub 9}(SLCBNBNO) with the charge neutrality, were synthesized by using conventional solid-state processing. Phase analysis was performed by X-ray diffraction analyses (XRD) and Raman spectroscopy. Microstructural morphology was assessed by the scanning electron microscopy (SEM). Structural, dielectric, piezoelectric, ferroelectric, and electromechanical properties of the SLCBNBNO ceramics were investigated. Piezoelectric properties were significantly enhanced compared to Sr{sub 0.6}(BiNa){sub 0.2}Bi{sub 2}Nb{sub 2}O{sub 9} (SBNBN) ceramic and the maximum of piezoelectric coefficient d{sub 33} of the SBNBN-LC6 ceramic was 32 pC/N with higher Curie temperature (T{sub c} ∼590 °C). In addition, mechanisms for the piezoelectric properties enhanced of the SBNBN-based ceramics were discussed.

The effect of phase assemblages, grain boundaries and domain structure on the local switching behavior of rare-earth modified bismuth ferrite ceramics

International Nuclear Information System (INIS)

Alikin, Denis O.; Turygin, Anton P.; Walker, Julian; Bencan, Andreja; Malic, Barbara; Rojac, Tadej; Shur, Vladimir Ya.; Kholkin, Andrei L.

2017-01-01

Piezoelectric properties and ferroelectric/ferroelastic domain switching behavior of polycrystalline ceramics are strongly influenced by local scale (i.e. <100 nm) phenomena, such as, the phase assemblages, domain structure, and defects. The method of ceramic synthesis strongly effects the local properties and thus plays a critical role in determining the macroscopic ferroelectric and piezoelectric performance. The link between synthesis and local scale properties of ferroelectrics is, however, rarely reported, especially for the emerging lead-free materials systems. In this work, we focus on samarium modified bismuth ferrite ceramics (Bi_0_._8_8Sm_0_._1_2FeO_3, BSFO) prepared by two methods: standard solid state reaction (SSR) and mechanochemi≿ally assisted synthesis (MAS). Each ceramic possesses different properties at the local scale and we used the piezoresponse force microscopy (PFM) complemented by transmission electron microscopy (TEM) to evaluate phase distribution, domain structure and polarization switching to show that an increase in the anti-polar phase assemblages within the polar matrix leads to notable changes in the local polarization switching. SSR ceramics exhibit larger internal bias fields relative to the MAS ceramics, and the grain boundaries produce a stronger effect on the local switching response. MAS ceramics were able to nucleate domains at lower electric-fields and grow them at faster rates, reaching larger final domain sizes than the SSR ceramics. Local evidence of the electric-field induced phase transition from the anti-ferroelectric Pbam to ferroelectric R3c phase was observed together with likely evidence of the existence of head-to-head/tail-to-tail charged domain walls and domain vortex core structures. By comparing the domain structure and local switching behavior of ceramics prepared by two different methods this work brings new insights the synthesis-structure-property relationship in lead-free piezoceramics.

Piezoelectric ceramic material, containing PbNb2O6, K2Nb2O6

International Nuclear Information System (INIS)

Fesenko, E.G.; Filip'ev, V.S.; Razumovskaya, O.N.; Cherner, Ya.E.; Rudkovskaya, L.M.; Zav'yalov, V.P.; Molchanova, R.A.; Kryshtop, V.G.; Panich, A.E.; Servuli, V.A.

1984-01-01

A new piezoelectric ceramic material including PbNb 2 O 6 , K 2 Nb 2 O 6 is prepared. Above the new material contains Nb 2 O 5 . The invention relates to piezotechnique. The principal advantage of this material for acoustic converters is high anisotropy of piezoelectric properties as well as high Curie temperature (T C =539-553 deg C). The composition containing 93.96 mole% PbNb 2 O 6 ; 2.48 mole% K 2 Nb 2 O 6 and 3.56 mole% Nb 2 O 5 has optimum content of parameters

Effects of pore shape and porosity on the properties of porous LNKN ceramics as bone substitute

International Nuclear Information System (INIS)

Wang Qi; Chen Qiang; Zhu Jianguo; Huang Chunpeng; Darvell, Brian W.; Chen Zhiqing

2008-01-01

A porous lead-free piezoelectric ceramic is investigated as direct bone substitute. Porous lithium sodium potassium niobate (Li 0.06 Na 0.5 K 0.44 )NbO 3 specimens were prepared by pore-forming method. Different volume fraction of ammonium oxalate monohydrate and poly(methyl methacrylate) were used as porogens to obtain different pore shape and porosity. Scanning electron microscopy showed a bicontinuous 3-3 structure of interconnected pores 150-250 μm in size. The piezoelectric constants and electromechanical coupling coefficients may be controlled by both size and shape of the porogens to tune for the best biological response. Such materials show promise for use as a piezoelectric composite bone substitute

Piezoelectric properties and thermal stabilities of cobalt-modified potassium bismuth titanate

International Nuclear Information System (INIS)

Guo, Zhen-Lei; Wang, Chun-Ming; Zhao, Tian-Long; Yu, Si-Long; Cao, Zhao-Peng

2013-01-01

The cobalt-modified potassium bismuth titanate (K 0.5 Bi 4.5 Ti 4 O 15 , KBT) piezoelectric ceramics have been prepared using conventional solid–state reaction. X-ray diffraction analysis revealed that the cobalt-modified KBT ceramics have a pure four-layer (m = 4) Aurivillius-type structure. The dielectric, ferroelectric, and piezoelectric properties of cobalt-modified KBT ceramics were investigated in detail. The piezoelectric activities of KBT ceramics were significantly improved by the cobalt modification. The reasons for piezoelectric activities enhancement with cobalt modification were given. The piezoelectric coefficient d 33 and Curie temperature T c for the 5 mol% cobalt-modified KBT ceramics (KBT-Co5) were found to be 28 pC/N and 575 °C, respectively. The DC resistivity, frequency constants (N p and N t ), and electromechanical properties at elevated temperature were investigated, indicating the cobalt-modified KBT piezoelectric ceramics possess stable piezoelectric properties up to 500 °C. The results show the cobalt-modified KBT ceramics are potential materials for high temperature piezoelectric applications. - Highlights: • We examine the piezoelectric properties of the cobalt-modified K 0.5 Bi 4.5 Ti 4 O 15 . • A high level of piezoelectric activities (d 33 = 28 pC/N) are obtained. • High Curie temperature (T c = 575 °C) is acquired for the optimal composition. • The Co-modified K 0.5 Bi 4.5 Ti 4 O 15 is promising as high temperature materials

Electric field-induced phase transitions and composition-driven nanodomains in rhombohedral-tetragonal potassium-sodium niobate-based ceramics

KAUST Repository

Lv, Xiang

2017-08-07

The mechanisms behind the high piezoelectricity of (K,Na)NbO3-based lead-free ceramics were investigated, including electric field-induced phase transitions and composition-driven nanodomains. The construction of a rhombohedral-tetragonal (R-T) phase boundary, confirmed using several advanced techniques, allowed a large piezoelectric constant (d33) of 450 ± 5 pC/N to be obtained in (1-x)K0.4Na0.6Nb0.945Sb0.055O3-xBi0.5Na0.5(Hf1-ySny)O3 (0 ≤ x ≤ 0.06 and 0 ≤ y ≤ 0.5) ceramics possessing an ultralow ΔUT-R of 7.4 meV. More importantly, the existence of an intermediate phase, i.e., the electric-induced phase (EIP), bridging the rhombohedral R [Ps//(111)] and tetragonal T [Ps//(001)] phases during the polarization rotation was demonstrated. Striped nanodomains (∼40 nm) that easily responded to external stimulation were also observed in the ceramics with an R-T phase. Thus, the enhanced piezoelectric properties originated from EIP and the striped nanodomains.

Bright upconversion luminescence and increased Tc in CaBi2Ta2O9:Er high temperature piezoelectric ceramics

International Nuclear Information System (INIS)

Peng Dengfeng; Wang Xusheng; Yao Xi; Xu Chaonan; Lin Jian; Sun Tiantuo

2012-01-01

Er 3+ doped CaBi 2 Ta 2 O 9 (CBT) bismuth layered-structure high temperature piezoelectric ceramics were synthesized by the traditional solid state method. The upconversion (UC) emission properties of Er 3+ doped CBT ceramics were investigated as a function of Er 3+ concentration and incident pump power. A bright green upconverted emission was obtained under excitation 980 nm at room temperature. The observed strong green and weak red emission bands corresponded to the transitions from 4 S 3/2 and 4 F 9/2 to 4 I 15/2 , respectively. The dependence of UC emission intensity on pumping power indicated that a three-photon process was involved in UC emissions. Studies of dielectric with temperature have also been carried out. Introduction of Er increased the Curie temperature of CBT, thus, making this ceramic suitable for sensor applications at higher temperatures. Because of its strong up-converted emission and increased Tc, the multifunctional high temperature piezoelectric ceramic may be useful in high temperature sensor, fluorescence thermometry, and optical-electro integration applications.

Fabrication and Piezoelectric Properties of Textured (Bi1/2K1/2)TiO3 Ferroelectric Ceramics

Science.gov (United States)

Nagata, Hajime; Saitoh, Masahiro; Hiruma, Yuji; Takenaka, Tadashi

2010-09-01

Textured (Bi1/2K1/2)TiO3 (BKT) ceramics were prepared by a reactive templated grain growth (RTGG) method to improve their piezoelectric properties. Also, a hot-pressing (HP) method was modified on the basis of RTGG method to obtain dense ceramics and promote the grain orientation. The textured BKT ceramics prepared by the RTGG and HP methods exhibited a relatively high orientation factor F of 0.82 and a high density ratio of 95-99%. Scanning electron microscopy (SEM) micrographs of the textured HP-BKT indicated a textured and poreless microstructure. In addition, the resistivity of the textured HP-BKT was 1.73×1013 Ω·cm. The piezoelectric strain constant d33 determined by means of resonance and antiresonance method was 125 pC/N for the direction parallel to the sheet-stacking direction of the RTGG process. From the measurement of field-induced stain, the normalized d33* (=Smax/Emax) at 80 kV/cm were 127 and 238 pm/V on the randomly oriented and textured samples (F=0.82) for the (∥) direction, respectively.

Texture and anisotropy in ferroelectric lead metaniobate

Science.gov (United States)

Iverson, Benjamin John

Ferroelectric lead metaniobate, PbNb2O6, is a piezoelectric ceramic typically used because of its elevated Curie temperature and anisotropic properties. However, the piezoelectric constant, d33, is relatively low in randomly oriented ceramics when compared to other ferroelectrics. Crystallographic texturing is often employed to increase the piezoelectric constant because the spontaneous polarization axes of grains are better aligned. In this research, crystallographic textures induced through tape casting are distinguished from textures induced through electrical poling. Texture is described using multiple quantitative approaches utilizing X-ray and neutron time-of-flight diffraction. Tape casting lead metaniobate with an inclusion of acicular template particles induces an orthotropic texture distribution. Templated grain growth from seed particles oriented during casting results in anisotropic grain structures. The degree of preferred orientation is directly linked to the shear behavior of the tape cast slurry. Increases in template concentration, slurry viscosity, and casting velocity lead to larger textures by inducing more particle orientation in the tape casting plane. The maximum 010 texture distributions were two and a half multiples of a random distribution. Ferroelectric texture was induced by electrical poling. Electric poling increases the volume of material oriented with the spontaneous polarization direction in the material. Samples with an initial paraelectric texture exhibit a greater change in the domain volume fraction during electrical poling than randomly oriented ceramics. In tape cast samples, the resulting piezoelectric response is proportional to the 010 texture present prior to poling. This results in property anisotropy dependent on initial texture. Piezoelectric properties measured on the most textured ceramics were similar to those obtained with a commercial standard.

Significantly enhanced piezoelectricity in low-temperature sintered Aurivillius-type ceramics with ultrahigh Curie temperature of 800 °C

International Nuclear Information System (INIS)

Cai, Kai; Huang, Chengcheng; Guo, Dong

2017-01-01

We report an Aurivillius-type piezoelectric ceramic (Ca 1−2x (LiCe) x Bi 4 Ti 3.99 Zn 0.01 O 15 ) that has an ultrahigh Curie temperature (T c ) around 800 °C and a significantly enhanced piezoelectric coefficient (d 33 ), comparable to that of textured ceramics fabricated using the complicated templating method. Surprisingly, the highest d 33 of 26 pC/N was achieved at an unexpectedly low sintering temperature (T s ) of only 920 °C (∼200 °C lower than usual) despite the non-ideal density. Study of different synthesized samples indicates that a relatively low T s is crucial for suppressing Bi evaporation and abnormal grain growth, which are indispensable for high resistivity and effective poling due to decreased carrier density and restricted anisotropic conduction. Because the layered structure is sensitive to lattice defects, controlled Bi loss is considered to be crucial for maintaining structural order and spontaneous polarization. This low-T s system is very promising for practical applications due to its high piezoelectricity, low cost and high reproducibility. Contrary to our usual understanding, the results reveal that a delicate balance of density, Bi loss and grain morphology achieved by adjusting the sintering temperature is crucial for the enhancing performance in Aurivillius-type high- T c ceramics. (paper)

Effect Of Electric Field Induced Texture On The Properties Of Piezoelectric Lead Zirconate Titanate

International Nuclear Information System (INIS)

Alkoy, S.

2010-01-01

Texturing a polycrystalline piezoelectric ceramic provide single-crystal like properties without experiencing any difficulties of single crystal growth process. This study reports a method to obtain texture in PbZr 0 .5Ti 0 .5O 3 ceramics by application of an electric field during gelation of a gelcast slurry. Gelcasting provides a means to lock the particles aligned under the application of a high electric field via gelation and this alignment in green body was retained after sintering. Monomer, cross linker and dispersant were dissolved in DI water and PZT powder was dispersed in this premix. Iniator and catalyzer were added to the slurry. An electric field was applied to the slurry for 30 min during gelation. XRD pattern of sintered samples indicates that PZT develops a tetragonal symmetry as a result of E-field applied during gelation. Dielectric constants and piezoelectric d 3 3 coefficients along and perpendicular to E-field are 1070 and 450 and 390 and 280 pC/N, respectively.

Theoretical and experimental research on the influence of multiple piezoelectric effects on physical parameters of piezoelectric actuator

Directory of Open Access Journals (Sweden)

Liping Shi

2015-04-01

Full Text Available Compared with the traditional actuator of machinery and electricity, the piezoelectric actuator has the advantages of a compact structure, small volume, no mechanical friction, athermancy and no electromagnetic interference. Therefore, it has high application value in the fields of MEMS, bioengineering, medical science and so on. This article draws conclusions from the influence of multiple piezoelectric effects on the physical parameters (dielectric coefficient, equivalent capacity, energy conversion and piezoelectric coefficient of piezoelectric actuators. These data from theoretical and experimental research show the following: (1 The rate between the dielectric coefficient of piezoelectric in mechanical freedom and clamping is obtained from the secondary direct piezoelectric effect, which enhances the dielectric property, increases the dielectric coefficient and decreases the coefficient of dielectric isolation; (2 Under external field, E n ( ex = E 1 , exterior stress T = 0, that is to say, under the boundary condition of mechanical freedom, piezoelectric can store electric energy and elasticity, which obtains power density, elastic density and an electromechanical coupling factor; (3 According to the piezoelectric strain S i ( 1 , piezoelectric displacement D m ( 2 and piezoelectric strain S i ( 3 of multiple piezoelectric effects, when the dielectric coefficient of the first converse piezoelectric effect ε33 is 1326 and the dielectric coefficient of the secondary direct piezoelectric effect increases to 3336, the dielectric coefficient of the ceramic chip increases. When the piezoelectric coefficient of the first converse piezoelectric effect d33 is 595 and the piezoelectric coefficient of the secondary direct piezoelectric effect decreases to 240, the piezoelectric coefficient of the ceramic chip will decrease. It is of major significance both in the applications and in basic theory to research the influence of multiple piezoelectric

Impedance-spectroscopy analysis and piezoelectric properties of Pb2KNb5O15 ceramics

International Nuclear Information System (INIS)

Rao, K. Sambasiva; Murali Krishna, P.; Swarna Latha, T.; Madhava Prasad, D.

2006-01-01

Preparation, dielectric, piezoelectric, hysteresis, impedance spectroscopy and AC conductivity studies in the Pb 0.8 K 0.4 Nb 2 O 6 ferroelectric ceramic have been presented. The Pb 1-x K 2x Nb 2 O 6 (PKN) characterized for ferroelectric and impedance spectroscopy studies from room temperature to 600 deg. C. The sample shows a single phase with orthorhombic structure from X-ray diffraction studies. The Cole-Cole plots and electric modulus plots at different temperatures are drawn. The results obtained from the impedance spectroscopy are analyzed, to understand the conductivity behavior of PKN. The piezoelectric constant, d 33 , has been found to be 75 x 10 -12 C/N

Density variation and piezoelectric properties of Ba(Ti1−xSnx)O3 ...

Indian Academy of Sciences (India)

diffraction method showed single phase perovskite structure. The density ... piezoelectric ceramics to replace toxic lead based materi- als. Among several groups ... electric field dependence of the material which leads to dif- ficulty in controlling ...

Design, Modeling and Optimization of a Piezoelectric Pressure Sensor based on a Thin-Film PZT Membrane Containing Nanocrystalline Powders

Directory of Open Access Journals (Sweden)

Vahid MOHAMMADI

2009-11-01

Full Text Available In this paper fabrication of a 0-3 ceramic/ceramic composite lead zirconate titanate, Pb(Zr0.52Ti0.48O3 thin film has been presented and then a pressure sensor based on multilayer thin-film PZT diaphragm contain of Lead Zirconate Titanate nanocrystalline powders was designed, modeled and optimized. Dynamics characteristics of this multilayer diaphragm have been investigated by ANSYS® FE software. By this simulation the effective parameters of the multilayer PZT diaphragm for improving the performance of a pressure sensor in different ranges of pressure are optimized. The optimized thickness ratio of PZT layer to SiO2 was given in the paper to obtain the maximum deflection of the multilayer thin-film PZT diaphragm. A 0-3 ceramic/ceramic composite lead zirconate titanate, Pb(Zr0.52Ti0.48O3 film has been developed to fabricate the pressure sensor by a hybrid sol gel process. PZT nanopowders fabricated via conventional sol gel method and uniformly dispersed in PZT precursor solution by an attrition mill. XRD analysis shows that perovskite structure would be formed due to the presence of a significant amount of ceramic nanopowders. This texture has a good effect on piezoelectric properties of perovskite structure. The film forms a strongly bonded network and less shrinkage occurs, so the films do not crack during process. Also the aspect ratio through this process would be increased. SEM micrographs indicated that PZT films were uniform, crack free and have a composite microstructure and a piezoelectric coefficient d31 of -40 pC.N-1 and d33 ranged from 50pm.N-1 to 60pm.N-1.

Combinatorial processing libraries for bulk BiFeO3-PbTiO3 piezoelectric ceramics

International Nuclear Information System (INIS)

Hu, W.; Tan, X.; Rajan, K.

2010-01-01

A high throughput approach for generating combinatorial libraries with varying processing conditions for bulk ceramics has been developed. This approach utilized the linear temperature gradient in a tube furnace to screen a whole temperature range for optimized preparation. With this approach, the processing of 0.98[0.6BiFeO 3 -0.4PbTiO 3 ]-0.02Pb(Mg 1/3 Nb 2/3 )O 3 ceramic powders and pellets for high-temperature piezoelectric applications was demonstrated to identify the best synthesis conditions for phase purity. The dielectric property measurement on the as-processed solid solution ceramics confirmed the high Curie temperature and the improved loss tangent with the Pb(Mg 1/3 Nb 2/3 )O 3 doping. (orig.)

Design and characterization of a carbon-nanotube-reinforced adhesive coating for piezoelectric ceramic discs

International Nuclear Information System (INIS)

Lanzara, G; Chang, F-K

2009-01-01

The silver paste electrode of piezoelectric (PZT) ceramic discs has been shown to produce a weak interface bond between a bare PZT and its paste coating under a peeling force. In this work, an investigation was conducted to reinforce the bond with a high density array of oriented carbon nanotube nano-electrodes (CNTs-NEA), between a bare PZT ceramic and a metal substrate. The ensuing design and fabrication of a carbon-nanotube-coated piezoelectric disc (CPZT) is presented along with a study of the bondline integrity of a CPZT mounted on a hosting structure. The CPZT has its electrode silver paste coating replaced with a high density array of CNTs-NEA. Mechanical tests were performed to characterize the shear strength of the bondline between CPZT discs and the substrate. The test results were compared with shear strengths of the bondlines made of pure non-conductive adhesive and adhesive with randomly mixed CNTs. The comparison showed the oriented CNT coating on PZTs could significantly enhance the interfacial shear strength. Through the microscopic examination, it was evident that the ratio between the CNT length (Lc) and the bond thickness (H) significantly influenced the bond strength of CPZT discs. Three major interface microstructure types and their corresponding failure modes for specific Lc/H values were identified. The study also showed that failure did not occur along the interface between the PZT ceramic element and the CNT coating

High energy storage density over a broad temperature range in sodium bismuth titanate-based lead-free ceramics.

Science.gov (United States)

Yang, Haibo; Yan, Fei; Lin, Ying; Wang, Tong; Wang, Fen

2017-08-18

A series of (1-x)Bi 0.48 La 0.02 Na 0.48 Li 0.02 Ti 0.98 Zr 0.02 O 3 -xNa 0.73 Bi 0.09 NbO 3 ((1-x)LLBNTZ-xNBN) (x = 0-0.14) ceramics were designed and fabricated using the conventional solid-state sintering method. The phase structure, microstructure, dielectric, ferroelectric and energy storage properties of the ceramics were systematically investigated. The results indicate that the addition of Na 0.73 Bi 0.09 NbO 3 (NBN) could decrease the remnant polarization (P r ) and improve the temperature stability of dielectric constant obviously. The working temperature range satisfying TCC 150  °C  ≤±15% of this work spans over 400 °C with the compositions of x ≥ 0.06. The maximum energy storage density can be obtained for the sample with x = 0.10 at room temperature, with an energy storage density of 2.04 J/cm 3 at 178 kV/cm. In addition, the (1-x)LLBNTZ-xNBN ceramics exhibit excellent energy storage properties over a wide temperature range from room temperature to 90 °C. The values of energy storage density and energy storage efficiency is 0.91 J/cm 3 and 79.51%, respectively, for the 0.90LLBNTZ-0.10NBN ceramic at the condition of 100 kV/cm and 90 °C. It can be concluded that the (1-x)LLBNTZ-xNBN ceramics are promising lead-free candidate materials for energy storage devices over a broad temperature range.

A Piezoelectric PZT Ceramic Mulitlayer Stack for Energy Harvesting Under Dynamic Forces

Science.gov (United States)

Xu, Tian-Bing; Siochi, Emilie J.; Kang, Jin Ho; Zuo, Lei; Zhou, Wanlu; Tang, Xiudong; Jiang, Xiaoning

2011-01-01

Piezoelectric energy harvesting transducers (PEHTs) are commonly used in motion/vibration energy scavenging devices. To date, most researchers have focused on energy harvesting at narrow bandwidths around the mechanical resonance frequency, and most piezoelectric harvesting devices reported in the literature have very low effective piezoelectric coefficient (d(sub eff)) (PZT ceramic multilayer stack (PZT-Stack) with high effective piezoelectric coefficient for high-performance PEHTs. The PZT-Stack is composed of 300 layers of 0.1 mm thick PZT plates, with overall dimensions of 32.4 mm X 7.0 mm X 7.0 mm. Experiments were carried out with dynamic forces in a broad bandwidth ranging from 0.5 Hz to 25 kHz. The measured results show that the effective piezoelectric coefficient of the PZT-stack is about 1 X 10(exp 5) pC/N at off-resonance frequencies and 1.39 X 10(exp 6) pC/N at resonance, which is order of magnitude larger than that of traditional PEHTs. The effective piezoelectric coefficients (d(sub eff)) do not change significantly with applied dynamic forces having root mean square (RMS) values ranging from 1 N to 40 N. In resonance mode, 231 mW of electrical power was harvested at 2479 Hz with a dynamic force of 11.6 N(sub rms), and 7.6 mW of electrical power was generated at a frequency of 2114 Hz with 1 N(sub rms) dynamic force. In off-resonance mode, an electrical power of 18.7 mW was obtained at 680 Hz with a 40 N(sub rms) dynamic force. A theoretical model of energy harvesting for the PZT-Stack is established. The modeled results matched well with experimental measurements. This study demonstrated that high effective piezoelectric coefficient structures enable PEHTs to harvest more electrical energy from mechanical vibrations or motions, suggesting an effective design for high-performance low-footprint PEHTs with potential applications in military, aerospace, and portable electronics. In addition, this study provides a route for using piezoelectric multilayer

Effect of ZnO Nanoparticles on the Sintering Behavior and Physical Properties of Bi0.5(Na0.8K0.2)0.5TiO3 Lead-Free Ceramics

Science.gov (United States)

Vuong, Le Dai; Truong-Tho, Nguyen

2017-11-01

Sintered Bi0.5(Na0.8K0.2)0.5TiO3 + x wt.% ZnO nanoparticle (BNKT- xZnOn) ceramics have been fabricated by conventional annealing with the aid of ultrasound waves for preliminary milling. Because of the presence of the liquid Bi2O3-ZnO phase at the eutectic point of 738°C, the sintering temperature decreased from 1150°C to 1000°C, and the morphology phase boundary of BNKT- xZnOn ceramics can be clarified by two separated peaks at (002)T and (200)T of 2 θ in the x-ray diffraction (XRD) patterns. The improvement of ferroelectric properties has been obtained for BNZT-0.2 wt.% ZnOn ceramics by the increase of remanent polarization up to 20.4 μC/cm2 and a decrease of electric coercive field down to 14.2 kV/cm. The piezoelectric parameters of the ceramic included a piezoelectric charge constant of d 31 = 78 pC/N; electromechanical coupling factors k p = 0.31 and k t = 0.34, larger than the values of 42 pC/N, 0.12 and 0.13, respectively, were obtained for the BNKT ceramics.

A Piezoelectric PZT Ceramic Mulitlayer Stack for Energy Harvesting Under Dynamic Forces

Science.gov (United States)

Xu, Tian-Bing; Siochi, Emilie J.; Kang, Jin Ho; Zuo, Lei; Zhou, Wanlu; Tang, Xiudong; Jiang, Xiaoning

2011-01-01

Piezoelectric energy harvesting transducers (PEHTs) are commonly used in motion/vibration energy scavenging devices. To date, most researchers have focused on energy harvesting at narrow bandwidths around the mechanical resonance frequency, and most piezoelectric harvesting devices reported in the literature have very low effective piezoelectric coefficient (d(sub eff)) (coefficients of about 100 pC/N. The level of harvested electrical power for CBPEHTs is on the order of microW even at resonance mode. In order to harvest more electrical energy across broader bandwidth, high effective piezoelectric coefficient structures are needed. In this study, we investigate a "33" longitudinal mode, piezoelectric PZT ceramic multilayer stack (PZT-Stack) with high effective piezoelectric coefficient for high-performance PEHTs. The PZT-Stack is composed of 300 layers of 0.1 mm thick PZT plates, with overall dimensions of 32.4 mm X 7.0 mm X 7.0 mm. Experiments were carried out with dynamic forces in a broad bandwidth ranging from 0.5 Hz to 25 kHz. The measured results show that the effective piezoelectric coefficient of the PZT-stack is about 1 X 10(exp 5) pC/N at off-resonance frequencies and 1.39 X 10(exp 6) pC/N at resonance, which is order of magnitude larger than that of traditional PEHTs. The effective piezoelectric coefficients (d(sub eff)) do not change significantly with applied dynamic forces having root mean square (RMS) values ranging from 1 N to 40 N. In resonance mode, 231 mW of electrical power was harvested at 2479 Hz with a dynamic force of 11.6 N(sub rms), and 7.6 mW of electrical power was generated at a frequency of 2114 Hz with 1 N(sub rms) dynamic force. In off-resonance mode, an electrical power of 18.7 mW was obtained at 680 Hz with a 40 N(sub rms) dynamic force. A theoretical model of energy harvesting for the PZT-Stack is established. The modeled results matched well with experimental measurements. This study demonstrated that high effective

Enhanced active piezoelectric 0-3 nanocomposites fabricated through electrospun nanowires

International Nuclear Information System (INIS)

Feenstra, Joel; Sodano, Henry A.

2008-01-01

The use of monolithic piezoceramic materials in sensing and actuation applications has become quite common over the past decade. However, these materials have several properties that limit their application in practical systems. These materials are very brittle due to the ceramic nature of the monolithic material, making them vulnerable to accidental breakage during handling and bonding procedures. In addition, they have very poor ability to conform to curved surfaces and result in large add-on mass associated with using a typically lead-based ceramic. These limitations have motivated the development of alternative methods of applying the piezoceramic material, including piezoceramic fiber composites and piezoelectric 0-3 composites (also known as piezoelectric paint). Piezoelectric paint is desirable because it can be spayed or painted on and can be used with abnormal surfaces. However, the piezoelectric paint developed in prior studies has resulted in low coupling, limiting its application. In order to increase the coupling of the piezoelectric paint, this effort has investigated the use of piezoelectric nanowires rather than spherical piezoelectric particle, which are difficult to strain when embedded in a polymer matrix. The piezoceramic wires were electrospun from a barium titanate (BaTiO 3 ) sol gel to produce fibers with 500-1000 nm diameters and subsequently calcinated to acquire perovskite BaTiO 3 . An active nanocomposite paint was formed using the resulting piezoelectric wires and was compared to the same paint with piezoelectric nanoparticles. The results show that the piezoceramic wires produce 0-3 nanocomposites with as high as 300% increase in electromechanical coupling

Piezoelectric micromotor using a metal-ceramic composite structure.

Science.gov (United States)

Koc, B; Bouchilloux, P; Uchino, K

2000-01-01

This paper presents a new piezoelectric micromotor design, in which a uniformly electroded piezoelectric ring bonded to a metal ring is used as the stator. Four inward arms at the inner circumference of the metal ring transfer radial displacements into tangential displacements. The rotor ends in a truncated cone shape and touches the tips of the arms. A rotation takes place by exciting coupled modes of the stator element, such as a radial mode and a second bending mode of the arms. The behavior of the free stator was analyzed using the ATILA finite element software. Torque vs. speed relationship was measured from the transient speed change with a motor load. A starting torque of 17 microNm was obtained at 20 Vrms. The main features of this motor are low cost and easy assembly because of a simple structure and small number of components.

Base Metal Co-Fired Multilayer Piezoelectrics

Directory of Open Access Journals (Sweden)

Lisheng Gao

2016-03-01

Full Text Available Piezoelectrics have been widely used in different kinds of applications, from the automobile industry to consumer electronics. The novel multilayer piezoelectrics, which are inspired by multilayer ceramic capacitors, not only minimize the size of the functional parts, but also maximize energy efficiency. Development of multilayer piezoelectric devices is at a significant crossroads on the way to achieving low costs, high efficiency, and excellent reliability. Concerning the costs of manufacturing multilayer piezoelectrics, the trend is to replace the costly noble metal internal electrodes with base metal materials. This paper discusses the materials development of metal co-firing and the progress of integrating current base metal chemistries. There are some significant considerations in metal co-firing multilayer piezoelectrics: retaining stoichiometry with volatile Pb and alkaline elements in ceramics, the selection of appropriate sintering agents to lower the sintering temperature with minimum impact on piezoelectric performance, and designing effective binder formulation for low pO2 burnout to prevent oxidation of Ni and Cu base metal.

Aggregate linear properties of ferroelectric ceramics and polycrystalline thin films: Calculation by the method of effective piezoelectric medium

Science.gov (United States)

Pertsev, N. A.; Zembilgotov, A. G.; Waser, R.

1998-08-01

The effective dielectric, piezoelectric, and elastic constants of polycrystalline ferroelectric materials are calculated from single-crystal data by an advanced method of effective medium, which takes into account the piezoelectric interactions between grains in full measure. For bulk BaTiO3 and PbTiO3 polarized ceramics, the dependences of material constants on the remanent polarization are reported. Dielectric and elastic constants are computed also for unpolarized c- and a-textured ferroelectric thin films deposited on cubic or amorphous substrates. It is found that the dielectric properties of BaTiO3 and PbTiO3 polycrystalline thin films strongly depend on the type of crystal texture. The influence of two-dimensional clamping by the substrate on the dielectric and piezoelectric responses of polarized films is described quantitatively and shown to be especially important for the piezoelectric charge coefficient of BaTiO3 films.

Surface-Selective Preferential Production of Reactive Oxygen Species on Piezoelectric Ceramics for Bacterial Killing

OpenAIRE

Tan, Guoxin; Wang, Shuangying; Zhu, Ye; Zhou, Lei; Yu, Peng; Wang, Xiaolan; He, Tianrui; Chen, Junqi; Mao, Chuanbin; Ning, Chengyun

2016-01-01

Reactive oxygen species (ROS) can be used to kill bacterial cells, and thus the selective generation of ROS from material surfaces is an emerging direction in antibacterial material discovery. We found the polarization of piezoelectric ceramic causes the two sides of the disk to become positively and negatively charged, which translate into cathode and anode surfaces in an aqueous solution. Because of the microelectrolysis of water, ROS are preferentially formed on the cathode surface. Conseq...

Electronically droplet energy harvesting using piezoelectric cantilevers

KAUST Repository

Al Ahmad, Mahmoud Al

2012-01-01

A report is presented on free falling droplet energy harvesting using piezoelectric cantilevers. The harvester incorporates a multimorph clamped-free cantilever which is composed of five layers of lead zirconate titanate piezoelectric thick films. During the impact, the droplet kinetic energy is transferred into the form of mechanical stress forcing the piezoelectric structure to vibrate. Experimental results show energy of 0.3 μJ per droplet. The scenario of moderate falling drop intensity, i.e. 230 drops per second, yields a total energy of 400 μJ. © 2012 The Institution of Engineering and Technology.

Theoretical and experimental investigations of thickness- stretch modes in 1-3 piezoelectric composites

International Nuclear Information System (INIS)

Yang, Z T; Zeng, D P; He, M; Wang, H

2015-01-01

Bulk piezoelectric ceramics operating in thickness-stretch (TSt) modes have been widely used in acoustic-related devices. However, the fundamental TSt waves are always coupled with other modes, and the occurrence of these spurious modes in bulk piezoelectric ceramics affects its performance. To suppress the spurious modes, 1-3 piezoelectric composites are promising candidates. However, theoretical modeling of multiphase ceramic composite objects is very complex. In this study, a 1-3 piezoelectric composite sample and a bulk piezoelectric sample are fabricated. The electrical impedance of these two samples are compared. A simple analytical TSt vibration mode from the three dimensional equations of linear piezoelectricity is used to model the performance of 1-3 piezoelectric composites. The theoretical results agree well with the experimental results. (paper)

A piezoelectric transformer

Science.gov (United States)

Won, C. C.

1993-01-01

This work describes a modeling and design method whereby a piezoelectric system is formulated by two sets of second-order equations, one for the mechanical system, and the other for the electrical system, coupled through the piezoelectric effect. The solution to this electromechanical coupled system gives a physical interpretation of the piezoelectric effect as a piezoelectric transformer that is a part of the piezoelectric system, which transfers the applied mechanical force into a force-controlled current source, and short circuit mechanical compliance into capacitance. It also transfers the voltage source into a voltage-controlled relative velocity input, and free motional capacitance into mechanical compliance. The formulation and interpretation simplify the modeling of smart structures and lead to physical insight that aids the designer. Due to its physical realization, the smart structural system can be unconditional stable and effectively control responses. This new concept has been demonstrated in three numerical examples for a simple piezoelectric system.

Effect of sintering condition on the microstructure and electrical properties of lead-free (Na0.5K0.5NbO3 - Bi0.5(Na0.83K0.170.5TiO3 ceramics

Directory of Open Access Journals (Sweden)

Wang Chun Huy

2017-01-01

Full Text Available In this work, the piezoelectric ceramic system of the (1-x(Na0.5K0.5NbO3 - xBi(Na0.83K0.17TiO3 with composition close to the morphotropic phase boundary is studied. (Na0.5K0.5NbO3 with 0∼5 mole% Bi(Na0.83K0.17TiO3 has been prepared following the conventional mixed oxide process. The effect of sintering time on the properties of 0.97(Na0.5K0.5NbO3-0.03Bi(Na0.83K0.17TiO3 ceramics is discussed. For 0.97(Na0.5K0.5NbO3-0.03Bi(Na0.83K0.17TiO3 ceramics, the electromechanical coupling coefficients of the thickness mode kt and the piezoelectric constant d33 reach 0.46 and 155 p/CN, respectively, at the sintering of 1100 °C for 3 h. Dielectric and piezoelectric properties have maximum values at the sintering temperature of 1100 °C for 5 h. For 0.97(Na0.5K0.5NbO3 -0.03Bi(Na0.83K0.17TiO3 ceramics, the electromechanical coupling coefficients of the thickness mode kt and the piezoelectric constant d33 reach 0.56 and 190, respectively, at the sintering of 1100 °C for 5 h. The effect of prolonging the sintering time to the 0.97(Na0.5K0.5NbO3-0.03Bi(Na0.83K0.17TiO3 system is a helpful method on ceramic processing to improve densification and properties.

Investigation of free vibration analysis of functionally graded annular piezoelectric plate using COMSOL

Science.gov (United States)

Sharma, Trivendra Kumar; Parashar, Sandeep Kumar

2018-05-01

In the present age functionally graded piezoelectric materials (FGPM) are increasingly being used as actuators and sensors. In spite of the fact that the piezoelectric coupling coefficient for shear d15 has much higher value in comparison to d31 or d33, it is far less utilized for the applications due to complex nature of the shear induced vibrations. In this work three dimensional free vibration analysis of functionally graded piezoelectric material annular plates with free-free boundary conditions is presented. The annular FGPM plate is polarized along the radial direction while the electric field is applied along the thickness direction inducing flexural vibrations of the plate due to d15 effect of functionally graded piezoelectric materials. The material properties are assumed to have a power law variation along the thickness. COMSOL Multiphysics is used to obtain the natural frequencies and modeshapes. Detailed numerical study is performed to ascertain the effect of variation in power law index and various geometrical parameters. The results presented shall be helpful in optimizing the existing applications and developing the new ones utilizing the FGPM annular plates.

Characterization and microstructure of porous lead zirconate titanate ...

Indian Academy of Sciences (India)

Unknown

need to have porous piezoelectric materials. These can be made by combining a PZT ceramic with a passive polymer or air phase. These materials greatly extend the range of properties offered by conventional PZT ceramics. More- over, porosity in the materials could reduce the effective acoustical impedance leading to an ...

The structure and piezoelectric properties of (Ca1-xSrx)Bi4Ti4O15 ceramics

International Nuclear Information System (INIS)

Zheng Liaoying; Li Guorong; Zhang Wangzhong; Chen, Daren; Yin Qinrui

2003-01-01

In this paper, the structure and piezoelectric properties of (Ca 1-x Sr x )Bi 4 Ti 4 O 15 ceramics (x=0-1.0) are investigated. The formation of single orthorhombic phase is verified by XRD. The dependence of dielectric and piezoelectric properties on x is also determined. The results show that the excellent properties could be found in the composition of x=0.4. In that composition, d 33 =14.9, T C =677 deg. C and the DC resistivity is decuplely higher than that of BST (SrBi 4 Ti 4 O 15 ) and CBT (CaBi 4 Ti 4 O 15 )

Ferroelectric and piezoelectric properties of lead-free BaTiO{sub 3} doped Bi{sub 0.5}Na{sub 0.5}TiO{sub 3} thin films from metal-organic solution deposition

Energy Technology Data Exchange (ETDEWEB)

Acharya, Susant Kumar [Division of Advanced Materials Engineering, Hydrogen and Fuel Cell Research Center, Chonbuk National University, Jeonju 561-756 (Korea, Republic of); Department of Semiconductor Science and Technology, Basic Research Laboratory (BRL), Semiconductor Physics Research Center (SPRC), Chonbuk National University, Jeonju 561-756 (Korea, Republic of); Lee, Sang-Kwon; Hyung, Jung-Hwan [Department of Semiconductor Science and Technology, Basic Research Laboratory (BRL), Semiconductor Physics Research Center (SPRC), Chonbuk National University, Jeonju 561-756 (Korea, Republic of); Yang, Yun-Ho; Kim, Bok-Hee [Division of Advanced Materials Engineering, Hydrogen and Fuel Cell Research Center, Chonbuk National University, Jeonju 561-756 (Korea, Republic of); Ahn, Byung-Guk, E-mail: bkahn@jbnu.ac.kr [Division of Advanced Materials Engineering, Hydrogen and Fuel Cell Research Center, Chonbuk National University, Jeonju 561-756 (Korea, Republic of)

2012-11-05

Highlights: Black-Right-Pointing-Pointer Lead-free BNT-BT thin films from an optimized metal-organic solution deposition. Black-Right-Pointing-Pointer Phase and microstructure evolution with annealing temperature. Black-Right-Pointing-Pointer A relatively low leakage current density. Black-Right-Pointing-Pointer Good dielectric constant of 613 at a frequency of 1 kHz. Black-Right-Pointing-Pointer High remanent polarization and piezoelectric constant comparable to PZT thin films. - Abstract: Lead-free 0.94Bi{sub 0.5}Na{sub 0.5}TiO{sub 3}-0.06BaTiO{sub 3} (BNT-BT) piezoelectric thin films were prepared by metal-organic solution deposition onto a Pt/Ti/SiO{sub 2}/Si substrate. A dense and well crystallized thin film with a perovskite phase was obtained by annealing these films at 700 Degree-Sign C. Atomic force microscopy showed that these films were smooth and crack-free with an average grain size on the order of 200 nm. Thin films of 356 nm thickness exhibited a small signal dielectric constant and a loss tangent at 1 kHz of 613 and 0.044, respectively. Ferroelectric hysteresis measurements indicated a remanent polarization value of 21.5 {mu}C/cm{sup 2} with a coercive field of 164.5 kV/cm. The leakage current density of the thin film was 4.08 Multiplication-Sign 10{sup -4} A/cm{sup 2} at an applied electric field of 200 kV/cm. A typical butterfly-shaped piezoresponse loop was observed and the effective piezoelectric coefficient (d{sub 33}) of the BNT-BT thin film was approximately 51.6 pm/V.

Enhanced pyroelectric and piezoelectric properties of PZT with aligned porosity for energy harvesting applications.

Science.gov (United States)

Zhang, Yan; Xie, Mengying; Roscow, James; Bao, Yinxiang; Zhou, Kechao; Zhang, Dou; Bowen, Chris R

2017-04-14

This paper demonstrates the significant benefits of exploiting highly aligned porosity in piezoelectric and pyroelectric materials for improved energy harvesting performance. Porous lead zirconate (PZT) ceramics with aligned pore channels and varying fractions of porosity were manufactured in a water-based suspension using freeze-casting. The aligned porous PZT ceramics were characterized in detail for both piezoelectric and pyroelectric properties and their energy harvesting performance figures of merit were assessed parallel and perpendicular to the freezing direction. As a result of the introduction of porosity into the ceramic microstructure, high piezoelectric and pyroelectric harvesting figures of merits were achieved for porous freeze-cast PZT compared to dense PZT due to the reduced permittivity and volume specific heat capacity. Experimental results were compared to parallel and series analytical models with good agreement and the PZT with porosity aligned parallel to the freezing direction exhibited the highest piezoelectric and pyroelectric harvesting response; this was a result of the enhanced interconnectivity of the ferroelectric material along the poling direction and reduced fraction of unpoled material that leads to a higher polarization. A complete thermal energy harvesting system, composed of a parallel-aligned PZT harvester element and an AC/DC converter, was successfully demonstrated by charging a storage capacitor. The maximum energy density generated by the 60 vol% porous parallel-connected PZT when subjected to thermal oscillations was 1653 μJ cm -3 , which was 374% higher than that of the dense PZT with an energy density of 446 μJ cm -3 . The results are beneficial for the design and manufacture of high performance porous pyroelectric and piezoelectric materials in devices for energy harvesting and sensor applications.

Preisach model of hysteresis for the Piezoelectric Actuator Drive

DEFF Research Database (Denmark)

Zsurzsan, Tiberiu-Gabriel; Andersen, Michael A. E.; Zhang, Zhe

2015-01-01

The Piezoelectric Actuator Drive (PAD) is a precise piezoelectric motor generating high-torque rotary motion, which employs piezoelectric stack actuators in a wobblestyle actuation to generate rotation. The piezoelectric stacked ceramics used as the basis for motion in the motor suffer from...

Effect of La and Mn on the properties of alkaline niobate-based piezoelectric ceramics

Directory of Open Access Journals (Sweden)

Henry E. Mgbemere

2016-03-01

Full Text Available Lead-free ferroelectric (K0.44Na0.52Li0.04(Nb0.86Ta0.1Sb0.04O3 ceramics co-doped with different amounts of both La and Mn have been produced using solid-state synthesis method. The relative density values of the unmodified sample are between 92 and 96% and decreases to ∼91% for the sample with 1 mol% of the co-doping. Bi-modal grain distribution is observed in the samples while the average grain size decreases with co-doping due to grain growth inhibition by pinning of the grain boundary movement. The diffraction patterns show a transformation from an orthorhombic phase to a pseudo-tetragonal phase with co-dopants addition. The Curie temperature and the tetragonal-orthorhombic transition temperatures are lowered from ∼9000 at 330 °C without modification to ∼4000 at temperatures below 250 °C with co-dopant addition. The dielectric loss values of the samples also decrease from ∼0.4 to 0.05 for temperatures up to 250 °C with co-doping. The remnant polarisation Pr of the samples decreases from ∼8.55 kV/cm to ∼6.57 kV/cm with co-dopant addition. The piezoelectric charge coefficient (d33, including the normalised strain values, also decrease from ∼400 pm/V and 220 pC/N to 157 pm/V and 159 pC/N, respectively with co-dopants up to 1 mol%.

Relaxor-PT Single Crystal Piezoelectric Sensors

Directory of Open Access Journals (Sweden)

Xiaoning Jiang

2014-07-01

Full Text Available Relaxor-PbTiO3 piezoelectric single crystals have been widely used in a broad range of electromechanical devices, including piezoelectric sensors, actuators, and transducers. This paper reviews the unique properties of these single crystals for piezoelectric sensors. Design, fabrication and characterization of various relaxor-PT single crystal piezoelectric sensors and their applications are presented and compared with their piezoelectric ceramic counterparts. Newly applicable fields and future trends of relaxor-PT sensors are also suggested in this review paper.

Determination of free carbon content in boron carbide ceramic powders

International Nuclear Information System (INIS)

Castro, A.R.M. de; Lima, N.B. de; Paschoal, J.O.A.

1990-01-01

Boron carbide is a ceramic material of technological importance due to its hardness and high chemical and thermal stabilities. Free carbon is always found as a process dependent impurity in boron carbide. The development of procedures for its detection is required because its presence leads to a degradation of the boron carbide properties. In this work, several procedures for determining free carbon content in boron carbide specimens are reported and discussed for comparison purposes. (author) [pt

Control of piezoelectricity in amino acids by supramolecular packing

Science.gov (United States)

Guerin, Sarah; Stapleton, Aimee; Chovan, Drahomir; Mouras, Rabah; Gleeson, Matthew; McKeown, Cian; Noor, Mohamed Radzi; Silien, Christophe; Rhen, Fernando M. F.; Kholkin, Andrei L.; Liu, Ning; Soulimane, Tewfik; Tofail, Syed A. M.; Thompson, Damien

2018-02-01

Piezoelectricity, the linear relationship between stress and induced electrical charge, has attracted recent interest due to its manifestation in biological molecules such as synthetic polypeptides or amino acid crystals, including gamma (γ) glycine. It has also been demonstrated in bone, collagen, elastin and the synthetic bone mineral hydroxyapatite. Piezoelectric coefficients exhibited by these biological materials are generally low, typically in the range of 0.1-10 pm V-1, limiting technological applications. Guided by quantum mechanical calculations we have measured a high shear piezoelectricity (178 pm V-1) in the amino acid crystal beta (β) glycine, which is of similar magnitude to barium titanate or lead zirconate titanate. Our calculations show that the high piezoelectric coefficients originate from an efficient packing of the molecules along certain crystallographic planes and directions. The highest predicted piezoelectric voltage constant for β-glycine crystals is 8 V mN-1, which is an order of magnitude larger than the voltage generated by any currently used ceramic or polymer.

Control of piezoelectricity in amino acids by supramolecular packing.

Science.gov (United States)

Guerin, Sarah; Stapleton, Aimee; Chovan, Drahomir; Mouras, Rabah; Gleeson, Matthew; McKeown, Cian; Noor, Mohamed Radzi; Silien, Christophe; Rhen, Fernando M F; Kholkin, Andrei L; Liu, Ning; Soulimane, Tewfik; Tofail, Syed A M; Thompson, Damien

2018-02-01

Piezoelectricity, the linear relationship between stress and induced electrical charge, has attracted recent interest due to its manifestation in biological molecules such as synthetic polypeptides or amino acid crystals, including gamma (γ) glycine. It has also been demonstrated in bone, collagen, elastin and the synthetic bone mineral hydroxyapatite. Piezoelectric coefficients exhibited by these biological materials are generally low, typically in the range of 0.1-10 pm V -1 , limiting technological applications. Guided by quantum mechanical calculations we have measured a high shear piezoelectricity (178 pm V -1 ) in the amino acid crystal beta (β) glycine, which is of similar magnitude to barium titanate or lead zirconate titanate. Our calculations show that the high piezoelectric coefficients originate from an efficient packing of the molecules along certain crystallographic planes and directions. The highest predicted piezoelectric voltage constant for β-glycine crystals is 8 V mN -1 , which is an order of magnitude larger than the voltage generated by any currently used ceramic or polymer.

Bright upconversion luminescence and increased Tc in CaBi{sub 2}Ta{sub 2}O{sub 9}:Er high temperature piezoelectric ceramics

Energy Technology Data Exchange (ETDEWEB)

Peng Dengfeng [Functional Materials Research Laboratory, Tongji University, 1239 Siping Road, Shanghai 200092 (China); National Institute of Advanced Industrial Science and Technology, Kyushu, 807-1 Shuku, Tosu, Saga 841-0052 (Japan); Wang Xusheng; Yao Xi [Functional Materials Research Laboratory, Tongji University, 1239 Siping Road, Shanghai 200092 (China); Xu Chaonan [National Institute of Advanced Industrial Science and Technology, Kyushu, 807-1 Shuku, Tosu, Saga 841-0052 (Japan); Lin Jian; Sun Tiantuo [College of Material Science and Engineering, Tongji University, 4800 Cao' an Highway, Shanghai 201804 (China)

2012-05-15

Er{sup 3+} doped CaBi{sub 2}Ta{sub 2}O{sub 9} (CBT) bismuth layered-structure high temperature piezoelectric ceramics were synthesized by the traditional solid state method. The upconversion (UC) emission properties of Er{sup 3+} doped CBT ceramics were investigated as a function of Er{sup 3+} concentration and incident pump power. A bright green upconverted emission was obtained under excitation 980 nm at room temperature. The observed strong green and weak red emission bands corresponded to the transitions from {sup 4}S{sub 3/2} and {sup 4}F{sub 9/2} to {sup 4}I{sub 15/2}, respectively. The dependence of UC emission intensity on pumping power indicated that a three-photon process was involved in UC emissions. Studies of dielectric with temperature have also been carried out. Introduction of Er increased the Curie temperature of CBT, thus, making this ceramic suitable for sensor applications at higher temperatures. Because of its strong up-converted emission and increased Tc, the multifunctional high temperature piezoelectric ceramic may be useful in high temperature sensor, fluorescence thermometry, and optical-electro integration applications.

Dielectric properties of (K0.5Na0.5)NbO3-(Bi0.5Li0.5)ZrO3 lead-free ceramics as high-temperature ceramic capacitors

Science.gov (United States)

Yan, Tianxiang; Han, Feifei; Ren, Shaokai; Ma, Xing; Fang, Liang; Liu, Laijun; Kuang, Xiaojun; Elouadi, Brahim

2018-04-01

(1 - x)K0.5Na0.5NbO3- x(Bi0.5Li0.5)ZrO3 (labeled as (1 - x)KNN- xBLZ) lead-free ceramics were fabricated by a solid-state reaction method. A research was conducted on the effects of BLZ content on structure, dielectric properties and relaxation behavior of KNN ceramics. By combining the X-ray diffraction patterns with the temperature dependence of dielectric properties, an orthorhombic-tetragonal phase coexistence was identified for x = 0.03, a tetragonal phase was determined for x = 0.05, and a single rhombohedral structure occurred at x = 0.08. The 0.92KNN-0.08BLZ ceramic exhibits a high and stable permittivity ( 1317, ± 15% variation) from 55 to 445 °C and low dielectric loss (≤ 6%) from 120 to 400 °C, which is hugely attractive for high-temperature capacitors. Activation energies of both high-temperature dielectric relaxation and dc conductivity first increase and then decline with the increase of BLZ, which might be attributed to the lattice distortion and concentration of oxygen vacancies.

Lead-free Ba0.8Ca0.2(ZrxTi1−x)O3 ceramics with large electrocaloric effect

International Nuclear Information System (INIS)

Asbani, B.; Dellis, J.-L.; Lahmar, A.; Gagou, Y.; El Marssi, M.; Courty, M.; Djellab, K.; Amjoud, M.; Mezzane, D.; Kutnjak, Z.

2015-01-01

The electrocaloric effect was investigated in lead-free Zr doped Ba 0.8 Ca 0.2 (Zr x Ti 1−x )O 3 (BCTZ) ceramics synthesized by a conventional sintering process. Room-temperature x-ray diffraction analysis showed that the tetragonal structure is obtained in BCTZ for x ≤ 0.08 and a pseudo cubic phase for x > 0.08. The dielectric spectroscopy and calorimetry revealed that the Curie temperature decreases as a consequence of Zr doping and that the BCTZ exhibits a first order ferroelectric phase transition. The electrocaloric effect was determined by the calculation of the electrocaloric change of temperature (ΔT) using the Maxwell relation based on the P–E hysteresis loops measured at different temperatures. A large electrocaloric responsivity ΔT/ΔE = 0.34 × 10 −6  Km/V was found for x = 0.04, which significantly exceeds of values found so far in other lead-free electrocaloric materials

Piezoelectric and mechanical properties of fatigue resistant, self-healing PZT-ionomer composites

NARCIS (Netherlands)

James, N.K.; Lafont, U.; Zwaag, S. van der; Groen, W.A.

2014-01-01

Piezoelectric ceramic-polymer composites with 0-3 connectivity were fabricated using lead zirconium titanate (PZT) powder dispersed in an ionomer (Zn ionomer) and its reference ethylene methacrylic acid copolymer (EMAA) polymer matrix. The PZT-Zn ionomer and PZT-EMAA composites were prepared by melt

Figure of merit comparison of PP-based electret and PVDF-based piezoelectric polymer energy harvesters

Science.gov (United States)

Mrlík, M.; Leadenham, S.; AlMaadeed, M. A.; Erturk, A.

2016-04-01

The harvesting of mechanical strain and kinetic energy has received great attention over the past two decades in order to power wireless electronic components such as those used in passive and active monitoring applications. Piezoelectric ceramics, such as PZT (lead zirconate titanate), constitute the most commonly used electromechanical interface in vibration energy harvesters. However, there are applications in which piezoelectric ceramics cannot be used due to their low allowable curvature and brittle nature. Soft polymer PVDF (polyvinylidene fluoride) is arguably the most popular non-ceramic soft piezoelectric energy harvester material for such scenarios. Another type of polymer that has received less attention is PP (polypropylene) for electret-based energy harvesting using the thickness mode (33- mode). This work presents figure of merit comparison of PP versus PVDF for off-resonant energy harvesting in thickness mode operation, revealing substantial advantage of PP over PVDF. For thickness mode energy harvesting scenarios (e.g. dynamic compression) at reasonable ambient vibration frequencies, the figure of merit for the maximum power output is proportional to the square of the effective piezoelectric strain constant divided by the effective permittivity constant. Under optimal conditions and for the same volume, it is shown that PP can generate more than two orders of magnitude larger electrical power as compared to PVDF due to the larger effective piezoelectric strain constant and lower permittivity of the former.

High-displacement spiral piezoelectric actuators

Science.gov (United States)

Mohammadi, F.; Kholkin, A. L.; Jadidian, B.; Safari, A.

1999-10-01

A high-displacement piezoelectric actuator, employing spiral geometry of a curved piezoelectric strip is described. The monolithic actuators are fabricated using a layered manufacturing technique, fused deposition of ceramics, which is capable of prototyping electroceramic components with complex shapes. The spiral actuators (2-3 cm in diameter) consisted of 4-5 turns of a lead zirconate titanate ceramic strip with an effective length up to 28 cm. The width was varied from 0.9 to 1.75 mm with a height of 3 mm. When driven by the electric field applied across the width of the spiral wall, the tip of the actuator was found to displace in both radial and tangential directions. The tangential displacement of the tip was about 210 μm under the field of 5 kV/cm. Both the displacement and resonant frequency of the spirals could be tailored by changing the effective length and wall width. The blocking force of the actuator in tangential direction was about 1 N under the field of 5 kV/cm. These properties are advantageous for high-displacement low-force applications where bimorph or monomorph actuators are currently employed.

Control of free-edge interlaminar stresses in composite laminates using piezoelectric actuators

International Nuclear Information System (INIS)

Huang, Bin; Soo Kim, Heung

2014-01-01

The control of free-edge interlaminar stresses in laminated composite structures using a stress function-based approach is proposed. The assumed stress fields satisfy pointwise traction and free boundary conditions at surfaces. Governing equations are derived using the principle of complementary virtual work. A general eigenvalue solution procedure was adopted to obtain accurate stress states of the laminated composite structure. The results obtained from the proposed method were compared with those obtained by three-dimensional finite element analyses. It was found that interlaminar stresses generated by mechanical loadings could be significantly reduced by applying proper electric fields to piezoelectric actuators, which were surface bonded or embedded in composite laminates. Locations of piezoelectric actuators also influenced the distributions of interlaminar stresses. The results provided that piezoelectric actuators have potential in the application to actively control interlaminar stresses in composite laminates. (paper)

Overview of NASA Langley's Piezoelectric Ceramic Packaging Technology and Applications

Science.gov (United States)

Bryant, Robert G.

2007-01-01

Over the past decade, NASA Langley Research Center (LaRC) has developed several actuator packaging concepts designed to enhance the performance of commercial electroactive ceramics. NASA LaRC focused on properly designed actuator and sensor packaging for the following reasons, increased durability, protect the working material from the environment, allow for proper mechanical and electrical contact, afford "ready to use" mechanisms that are scalable, and develop fabrication methodology applicable to any active material of the same physical class. It is more cost effective to enhance or tailor the performance of existing systems, through innovative packaging, than to develop, test and manufacture new materials. This approach led to the development of several solid state actuators that include THUNDER, the Macrofiber Composite or (MFC) and the Radial Field Diaphragm or (RFD). All these actuators are fabricated using standard materials and processes derived from earlier concepts. NASA s fabrication and packaging technology as yielded, piezoelectric actuators and sensors that are easy to implement, reliable, consistent in properties, and of lower cost to manufacture in quantity, than their predecessors (as evidenced by their continued commercial availability.) These piezoelectric actuators have helped foster new research and development in areas involving computational modeling, actuator specific refinements, and engineering system redesign which led to new applications for piezo-based devices that replace traditional systems currently in use.

Piezoelectric Lead Zirconate Titanate (PZT) Ring Shaped Contour-Mode MEMS Resonators

Science.gov (United States)

Kasambe, P. V.; Asgaonkar, V. V.; Bangera, A. D.; Lokre, A. S.; Rathod, S. S.; Bhoir, D. V.

2018-02-01

Flexibility in setting fundamental frequency of resonator independent of its motional resistance is one of the desired criteria in micro-electromechanical (MEMS) resonator design. It is observed that ring-shaped piezoelectric contour-mode MEMS resonators satisfy this design criterion than in case of rectangular plate MEMS resonators. Also ring-shaped contour-mode piezoelectric MEMS resonator has an advantage that its fundamental frequency is defined by in-plane dimensions, but they show variation of fundamental frequency with different Platinum (Pt) thickness referred as change in ratio of fNEW /fO . This paper presents the effects of variation in geometrical parameters and change in piezoelectric material on the resonant frequencies of Platinum piezoelectric-Aluminium ring-shaped contour-mode MEMS resonators and its electrical parameters. The proposed structure with Lead Zirconate Titanate (PZT) as the piezoelectric material was observed to be a piezoelectric material with minimal change in fundamental resonant frequency due to Platinum thickness variation. This structure was also found to exhibit extremely low motional resistance of 0.03 Ω as compared to the 31-35 Ω range obtained when using AlN as the piezoelectric material. CoventorWare 10 is used for the design, simulation and corresponding analysis of resonators which is Finite Element Method (FEM) analysis and design tool for MEMS devices.

Structured Piezoelectric Composites : Materials and Applications

NARCIS (Netherlands)

Van den Ende, D.A.

2012-01-01

The piezoelectric effect, which causes a material to generate a voltage when it deforms, is very suitable for making integrated sensors, and (micro-) generators. However, conventional piezoelectric materials are either brittle ceramics or certain polymers with a low thermal stability, which limits

Cross-poling textures in a lead zirconate titanate piezoelectric material

International Nuclear Information System (INIS)

Wan, Shan; Bowman, Keith J.

2000-01-01

Tetragonal ferroelectric materials are polarized to induce the anisotropy necessary for the piezoelectric effect. This poling of the material is inherently an orientation process. Pole figure texture measurements of poling and cross-poling in a lead zirconate titanate Navy VI material show domain motion. The resulting axisymmetric and three-dimensional textures demonstrate the contribution of 90 degree sign domain motion to piezoelectricity. Cross-poling results in strong orientations with lower applied fields than in the initial poling steps. (c) 2000 Materials Research Society

Electrical and thermal properties of lead titanate glass ceramics

International Nuclear Information System (INIS)

Shankar, J.; Deshpande, V.K.

2011-01-01

Glass samples with composition of (50-X)PbO-(25+X)TiO 2 -25B 2 O 3 (where X=0, 5, 10 and 12.5 mol%) were prepared using conventional quenching technique. The glass transition temperature, T g and crystallization temperature T c were determined from the DTA. These glass samples were converted to glass ceramics by following two stage heat treatment schedule. The glass ceramic samples were characterized by XRD, SEM and dielectric constant measurements. The XRD results revealed the formation of ferroelectric lead titanate (PT) as a major crystalline phase in the glass ceramics. The density increases and the CTE decreases for all glass ceramics with increase in X (mol%). This may be attributed to increase in PT phase. The SEM results which show rounded crystallites of lead titanate, also supports other results. Hysteresis loops observed at room temperature confirms the ferroelectric nature of glass ceramics. The optimized glass ceramic sample exhibits high dielectric constant which is of technical importance. -- Research Highlights: →Lead titanate glass ceramics prepared by conventional quenching technique. →Lead titanate is a major crystalline phase in the glass ceramics. →The ferroelectric nature of glass ceramics is confirmed by the hysteresis study. →The high value of ε observed at room temperature is quite promising in the study.

Improved ferroelectric, piezoelectric and electrostrictive properties of dense BaTiO{sub 3} ceramic

Energy Technology Data Exchange (ETDEWEB)

Baraskar, Bharat G.; Kakade, S. G.; Kambale, R. C., E-mail: rckambale@gmail.com; Kolekar, Y. D., E-mail: ydk@physics.unipune.ac.in [Department of Physics, Savitribai Phule Pune University, Pune, Maharashtra, India 411 007 (India); James, A. R. [Defence Metallurgical Research Laboratory, Kanchanbagh P.O., Hyderabad, India - 500 058 (India)

2016-05-23

The ferroelectric, piezoelectric and electrostrictive properties of BaTiO{sub 3} (BT) dense ceramic synthesized by solid-state reaction were investigated. X-ray diffraction study confirmed tetragonal crystal structure having c/a ~1.0144. The dense microstructure was evidenced from morphological studies with an average grain size ~7.8 µm. Temperature dependent dielectric measurement showed the maximum values of dielectric constant, ε{sub r} = 5617 at Curie temperature, T{sub c} = 125 °C. The saturation and remnant polarization, P{sub sat.} = 24.13 µC/cm{sup 2} and P{sub r} =10.42 µC/cm{sup 2} achieved respectively for the first time with lower coercive field of E{sub c}=2.047 kV/cm. The polarization current density-electric field measurement exhibits the peaking characteristics, confirms the saturation state of polarization for BT. The strain-electric field measurements revealed the “sprout” shape nature instead of typical “butterfly loop”. This shows the excellent converse piezoelectric response with remnant strain ~ 0.212% and converse piezoelectric constant d*{sub 33} ~376.35 pm/V. The intrinsic electrostrictive coefficient was deduced from the variation of strain with polarization with electrostrictive coefficient Q{sub 33}~ 0.03493m{sup 4}/C{sup 2}.

Systematic modeling for free stators of rotary - Piezoelectric ultrasonic motors

DEFF Research Database (Denmark)

Mojallali, Hamed; Amini, Rouzbeh; Izadi-Zamanabadi, Roozbeh

2007-01-01

An equivalent circuit model with complex elements is presented in this paper to describe the free stator model of traveling wave piezoelectric motors. The mechanical, dielectric and piezoelectric losses associated with the vibrator are considered by introducing the imaginary part to the equivalent...... circuit elements. The determination of the complex circuit elements is performed by using a new simple iterative method. The presented method uses information about five points of the stator admittance measurements. The accuracy of the model in fitting to the experimental data is verified by using...

Boosting the Recoverable Energy Density of Lead-Free Ferroelectric Ceramic Thick Films through Artificially Induced Quasi-Relaxor Behavior.

Science.gov (United States)

Peddigari, Mahesh; Palneedi, Haribabu; Hwang, Geon-Tae; Lim, Kyung Won; Kim, Ga-Yeon; Jeong, Dae-Yong; Ryu, Jungho

2018-06-08

Dielectric ceramic film capacitors, which store energy in the form of electric polarization, are promising for miniature pulsed power electronic device applications. For a superior energy storage performance of the capacitors, large recoverable energy density, along with high efficiency, high power density, fast charge/discharge rate, and good thermal/fatigue stability, is desired. Herein, we present highly dense lead-free 0.942[Na 0.535 K 0.480 NbO 3 ]-0.058LiNbO 3 (KNNLN) ferroelectric ceramic thick films (∼5 μm) demonstrating remarkable energy storage performance. The nanocrystalline KNNLN thick film fabricated by aerosol deposition (AD) process and annealed at 600 °C displayed a quasi-relaxor ferroelectric behavior, which is in contrast to the typical ferroelectric nature of the KNNLN ceramic in its bulk form. The AD film exhibited a large recoverable energy density of 23.4 J/cm 3 , with an efficiency of over 70% under the electric field of 1400 kV/cm. Besides, an ultrahigh power density of 38.8 MW/cm 3 together with a fast discharge speed of 0.45 μs, good fatigue endurance (up to 10 6 cycles), and thermal stability in a wide temperature range of 20-160 °C was also observed. Using the AD process, we could make a highly dense microstructure of the film containing nano-sized grains, which gave rise to the quasi-relaxor ferroelectric characteristics and the remarkable energy storage properties.

Effect of orthorhombic distortion on dielectric and piezoelectric properties of CaBi4Ti4O15 ceramics

International Nuclear Information System (INIS)

Tanwar, Amit; Sreenivas, K.; Gupta, Vinay

2009-01-01

High temperature bismuth layered piezoelectric and ferroelectric ceramics of CaBi 4 Ti 4 O 15 (CBT) have been prepared using the solid state route. The formation of single phase material with orthorhombic structure was verified from x-ray diffraction and Raman spectroscopy. The orthorhombic distortion present in the CBT ceramic sintered at 1200 deg. C was found to be maximum. A sharp phase transition from ferroelectric to paraelectric was observed in the temperature dependent dielectric studies of all CBT ceramics. The Curie's temperature (T c =790 deg. C) was found to be independent of measured frequency. The behavior of ac conductivity as a function of frequency (100 Hz-1 MHz) at low temperatures ( 33 ). The observed results indicate the important role of orthorhombic distortion in determining the improved property of multicomponent ferroelectric material.

Large recoverable electrostrain in Mn-doped (Ba,Sr) TiO3 ceramics

International Nuclear Information System (INIS)

Zhang, L.X.; Chen, W.; Ren, X.

2004-01-01

In this letter we demonstrate that with a different principle, BaTiO 3 ceramics, so far considered as inferior piezoelectrics compared with Pb(Zr,Ti)O 3 (PZT), can show a large recoverable electrostrain. This principle utilizes a point-defect-mediated reversible domain switching mechanism, which can in theory generate 0.368% strain for BaTiO 3 ceramics at the best condition. Experimental results showed that, after aging at room temperature, 1.0 mol % Mn-doped (Ba 0.95 Sr 0.05 )TiO 3 ceramics generate a large recoverable nonlinear strain of about 0.12%-0.15% at a field of 3 kV/mm. This value exceeds that of conventional hard PZT piezoelectric ceramics. A microscopic model for the domain-related electrostrain effect in ceramics is proposed. It is also found that the large electrostrain effect is quite stable with respect to both changing frequency and fatigue cycles. Large electrostrain remains recoverable down to 0.05 Hz and after 10 000 cycles. These results demonstrate the potential of our approach in achieving large recoverable electrostrain in environmental-friendly (Pb-free) ceramics

Towards a digital sound reconstruction MEMS device: Characterization of a single PZT based piezoelectric actuator

KAUST Repository

Carreno, Armando Arpys Arevalo; Conchouso Gonzalez, David; Castro, David; Jaber, Nizar; Younis, Mohammad I.; Foulds, Ian G.

2015-01-01

of acoustic actuators. These actuators consist of a flexible membrane fabricated using polyimide, which is actuated using a Lead-Zirconate-Titanate (PZT) piezoelectric ceramic layer working in the d31 actuation mode. The dimensions of the membrane are of 1mm

Concept of ceramics-free coaxial waveguide

International Nuclear Information System (INIS)

Arai, Hiroyuki

1994-01-01

A critical key point of the ITER IC antenna is ceramics support of an internal conductor of a coaxial antenna feeder close to the plasma, because dielectric loss tangent of ceramics enhanced due to neutron irradiation limits significantly the antenna injection power. This paper presents a ceramics-free waveguide to overcome this problem by a T-shaped ridged waveguide with arms for the mechanical support. This ridged waveguide has a low cutoff frequency for its small cross section, which has been proposed for the conceptual design study of Fusion Experimental Reactor (FER) IC system and the high frequency supplementary IC system for ITER. This paper presents the concept of ceramics-free coaxial waveguide consisting of the coaxial-line and the ridged waveguide. This paper also presents the cutoff frequency and the electric field distribution of the ridged waveguide calculated by a finite element method and an approximate method. The power handling capability more than 3 MW is evaluated by using the transmission-line theory and the optimized antenna impedance considering the ITER plasma parameters. We verify this transmission-line model by one-tenth scale models experimentally. (author)

Synthesis and characterization of lead-free ternary component BST–BCT–BZT ceramic capacitors

Directory of Open Access Journals (Sweden)

Venkata Sreenivas Puli

2014-04-01

Full Text Available Polycrystalline sample of lead-free 1/3(Ba0.70Sr0.30TiO3 + 1/3(Ba0.70Ca0.30TiO3 + 1/3(BaZr0.20Ti0.80O3(BST-BCT-BZT ceramic was synthesized by solid state reaction method. Phase purity and crystal structure of as-synthesized materials was confirmed by X-ray diffraction (XRD. Temperature-dependent dielectric permittivity studies demonstrated frequency-independent behavior, indicating that the studied sample has typical diffuse phase transition behavior with partial thermal hysteresis. A ferroelectric phase transition between cubic and tetragonal phase was noticed near room temperature (~ 330 K. Bulk P–E hysteresis loop showed a saturation polarization of 20.4 μC/cm2 and a coercive field of ~ 12.78 kV/cm at a maximum electric field of ~ 115 kV/cm. High dielectric constant (ε ~ 5773, low dielectric loss (tan δ ~ 0.03 were recorded at room temperature. Discharge energy density of 0.44 J/cm3 and charge energy density of 1.40 J/cm3 were calculated from nonlinear ferroelectric hysteresis loop at maximum electric field. Dielectric constant at variable temperatures and electric fields, ferroelectric to paraelectric phase transition and energy storage properties were thoroughly discussed.

Electrical and mechanical properties of 0.5Ba (Zr0.2Ti0.8)O3-0.5 (Ba0.7Ca0.3)TiO3 (BZT-BCT) lead free ferroelectric ceramics reinforced with Al2O3 nano-oxide

International Nuclear Information System (INIS)

Adhikari, Prativa; Mazumder, R.

2014-01-01

Piezoelectric ceramics are widely used as actuator, resonator, and spark igniter. Recently, much attention has been paid to prepare 0.5Ba (Zr 0.2 Ti 0.8 )O 3 -0.5 (Ba 0.7 Ca 0.3 )TiO 3 (BZT-BCT) piezoelectric ceramics because of its good dielectric, piezoelectric properties and environment friendly nature. However, piezoelectric ceramics based on BaTiO 3 suffer from low reliability and poor mechanical properties such as strength and toughness. For practical application improvement of the mechanical properties of BaTiO 3 -based ceramics is strongly required. A novel method has been used to improve the mechanical properties of structural ceramics by reinforcement of oxide (Al 2 O 3 , MgO, ZrO 2 and Stabilized-ZrO 2 ) or non-oxide (SiC) particles. It is well known that electrical properties of ferroelectric ceramics generally degrade with non-ferroelectric additives and decrease in sinterability usually encountered with refractory oxide additives. Use of nano-oxide additives may drastically reduce the amount of additive and electrical property may not degrade much. In this report we would show the electrical and mechanical properties of BZT-BCT with Al 2 O 3 nano oxide additive. Modified BZT-BCT nanocomposites were prepared by mixing and sintering of solid state synthesized Zr, Ca modified barium titanate powder and small amount (0.1-2.0 vol %) of nano-oxides, i.e. Al 2 O 3 . Effect of sintering temperature, time, particle size of the nano-oxide additives on electrical (dielectric constant, loss factor, Curie temperature, d 33 ) and mechanical (flexural strength, fracture toughness, hardness) properties were studied. We obtained ∼ 94% dense BZT-BCT reinforced with Al 2 O 3 nano-oxide at 1300℃ without degrading electrical properties (dielectric constant (4850), low dissipation factor (0.0242)) and superior mechanical properties (flexural strength - 60.3 MPa, Vickers hardness-750-800 MPa). (author)

Ferroelectric and ferroelastic domain structures in piezoelectric ceramics

International Nuclear Information System (INIS)

Bursill, L.A.; Julin Peng.

1990-01-01

A discussion of the results of conventional and high-resolution high-voltage electron microscopic studies of two ferroelectrics, barium sodium niobate and lead zirconium titanate is presented. It is shown that a rich variety of information such as ferroelectric and/or ferroelastic domains discommensurations versus antiphase boundaries, extended versus localized chemical defects and multiphase versus grain boundaries, become accessible in both single crystal and polycrystalline piezoelectrics, when a combination of high-resolution and conventional electron optical techniques is used. 15 refs., 8 figs

Structure and high-piezoelectricity in lead oxide solid solutions

NARCIS (Netherlands)

Noheda, B.

2002-01-01

A review of the recent advances in the understanding of piezoelectricity in lead oxide solid solutions is presented, giving special attention to the structural aspects. It has now become clear that the very high electromechanical response in these materials is directly related to the existence of

Energy storage properties and relaxor behavior of lead-free Ba1-xSm2x/3Zr0.15Ti0.85O3 ceramics.

Science.gov (United States)

Sun, Zheng; Li, Lingxia; Yu, Shihui; Kang, Xinyu; Chen, Siliang

2017-10-24

Lead-free Ba 1-x Sm 2x/3 Zr 0.15 Ti 0.85 O 3 (BSZT) ceramics were synthesized by a solid state reaction route. The microstructure, dielectric relaxor behavior and energy storage properties of BSZT ceramics were studied. The growth of grain size was suppressed with the increase of Sm addition and kept in the submicrometer scale. Successive substitution of Sm 3+ for Ba 2+ disrupted the long-range dipole and promoted the increase of polar nano-region (PNR) size, resulting in the enhanced degree of relaxor behavior. The increasing PNR size also lead to the slimmer hysteresis loops and improved the energy storage efficiency. Furthermore, high saturated polarization (P max ) and low remnant polarization (P r ) were obtained due to the formation of defect dipoles, which facilitated the switch of PNRs and contributed to the enhancement of energy storage density. The x = 0.003 sample was found to exhibit a higher energy storage density of 1.15 J cm -3 and an energy storage efficiency of 92%. The result revealed that the BSZT ceramics may be a good candidate for energy storage application.

Piezoelectric Resonance Investigation of Zr-rich PZT at Room Temperature

NARCIS (Netherlands)

Cereceda, N.; Noheda, B.; Fernandez-del-Castillo, J.R.; Gonzalo, J.A.; Frutos, J. De

1999-01-01

We study the piezoelectric resonances in poled PZT ceramics by means of a microscopic model. It connects the microscopic vibrations of the ionic units, cooperatively producing the piezoelectric effect, with the macroscopic piezoelectric parameters. The behaviour at the resonance is well described in

Effect of material constants on power output in piezoelectric vibration-based generators.

Science.gov (United States)

Takeda, Hiroaki; Mihara, Kensuke; Yoshimura, Tomohiro; Hoshina, Takuya; Tsurumi, Takaaki

2011-09-01

A possible power output estimation based on material constants in piezoelectric vibration-based generators is proposed. A modified equivalent circuit model of the generator was built and was validated by the measurement results in the generator fabricated using potassium sodium niobate-based and lead zirconate titanate (PZT) ceramics. Subsequently, generators with the same structure using other PZT-based and bismuth-layered structure ferroelectrics ceramics were fabricated and tested. The power outputs of these generators were expressed as a linear functions of the term composed of electromechanical coupling coefficients k(sys)(2) and mechanical quality factors Q*(m) of the generator. The relationship between device constants (k(sys)(2) and Q*(m)) and material constants (k(31)(2) and Q(m)) was clarified. Estimation of the power output using material constants is demonstrated and the appropriate piezoelectric material for the generator is suggested.

Ultrasonic power transfer from a spherical acoustic wave source to a free-free piezoelectric receiver: Modeling and experiment

Energy Technology Data Exchange (ETDEWEB)

Shahab, S.; Gray, M.; Erturk, A., E-mail: alper.erturk@me.gatech.edu [G. W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332 (United States)

2015-03-14

Contactless powering of small electronic components has lately received growing attention for wireless applications in which battery replacement or tethered charging is undesired or simply impossible, and ambient energy harvesting is not a viable solution. As an alternative to well-studied methods of contactless energy transfer, such as the inductive coupling method, the use of ultrasonic waves transmitted and received by piezoelectric devices enables larger power transmission distances, which is critical especially for deep-implanted electronic devices. Moreover, energy transfer by means of acoustic waves is well suited in situations where no electromagnetic fields are allowed. The limited literature of ultrasonic acoustic energy transfer is mainly centered on proof-of-concept experiments demonstrating the feasibility of this method, lacking experimentally validated modeling efforts for the resulting multiphysics problem that couples the source and receiver dynamics with domain acoustics. In this work, we present fully coupled analytical, numerical, and experimental multiphysics investigations for ultrasonic acoustic energy transfer from a spherical wave source to a piezoelectric receiver bar that operates in the 33-mode of piezoelectricity. The fluid-loaded piezoelectric receiver under free-free mechanical boundary conditions is shunted to an electrical load for quantifying the electrical power output for a given acoustic source strength of the transmitter. The analytical acoustic-piezoelectric structure interaction modeling framework is validated experimentally, and the effects of system parameters are reported along with optimal electrical loading and frequency conditions of the receiver.

Ultrasonic power transfer from a spherical acoustic wave source to a free-free piezoelectric receiver: Modeling and experiment

International Nuclear Information System (INIS)

Shahab, S.; Gray, M.; Erturk, A.

2015-01-01

Contactless powering of small electronic components has lately received growing attention for wireless applications in which battery replacement or tethered charging is undesired or simply impossible, and ambient energy harvesting is not a viable solution. As an alternative to well-studied methods of contactless energy transfer, such as the inductive coupling method, the use of ultrasonic waves transmitted and received by piezoelectric devices enables larger power transmission distances, which is critical especially for deep-implanted electronic devices. Moreover, energy transfer by means of acoustic waves is well suited in situations where no electromagnetic fields are allowed. The limited literature of ultrasonic acoustic energy transfer is mainly centered on proof-of-concept experiments demonstrating the feasibility of this method, lacking experimentally validated modeling efforts for the resulting multiphysics problem that couples the source and receiver dynamics with domain acoustics. In this work, we present fully coupled analytical, numerical, and experimental multiphysics investigations for ultrasonic acoustic energy transfer from a spherical wave source to a piezoelectric receiver bar that operates in the 33-mode of piezoelectricity. The fluid-loaded piezoelectric receiver under free-free mechanical boundary conditions is shunted to an electrical load for quantifying the electrical power output for a given acoustic source strength of the transmitter. The analytical acoustic-piezoelectric structure interaction modeling framework is validated experimentally, and the effects of system parameters are reported along with optimal electrical loading and frequency conditions of the receiver

A-site substitution effect of strontium on bismuth layered CaBi4Ti4O15 ceramics on electrical and piezoelectric properties

International Nuclear Information System (INIS)

Tanwar, Amit; Verma, Maya; Gupta, Vinay; Sreenivas, K.

2011-01-01

Strontium substituted CaBi 4 Ti 4 O 15 ceramics with the chemical formula Ca 1-x Sr x Bi 4 Ti 4 O 15 (CSBT) (x = 0.0-1.0) have been prepared through conventional solid state route. The formation of single phase material with orthorhombic structure was verified from X-ray diffraction with incorporation of Sr substitution. Decrease in a-axis displacement of Bi ion in the perovskite structure in the CSBT ceramics were observed from the relative changes in soft mode (20 cm -1 ) in the Raman spectra, and increase in Sr incorporation shows the shift in ferroelectric to paraelectric phase transition temperature. The dielectric properties for all the CSBT ceramic compositions are studied as a function of temperature over the frequency range of 100 Hz-1 MHz. Curie's temperature was found to be function of Sr substitution and with increase in the Sr concentration the phase transition becomes sharper and phase transition temperature gets shifted towards lower temperature (790-545 deg. C). The behavior of ac conductivity as a function of frequency (100 Hz-1 MHz) at low temperature ( 33 ) whereas piezoelectric charge coefficient values were found comparable to that of PZT at room temperature. Relative changes in soft modes due to Sr incorporation results in high piezoelectricity in the CSBT ceramics.

A-site substitution effect of strontium on bismuth layered CaBi{sub 4}Ti{sub 4}O{sub 15} ceramics on electrical and piezoelectric properties

Energy Technology Data Exchange (ETDEWEB)

Tanwar, Amit, E-mail: amit07tanwar@gmail.com [Department of Physics and Astrophysics, University of Delhi, Delhi 110007 (India); Verma, Maya; Gupta, Vinay; Sreenivas, K. [Department of Physics and Astrophysics, University of Delhi, Delhi 110007 (India)

2011-10-17

Strontium substituted CaBi{sub 4}Ti{sub 4}O{sub 15} ceramics with the chemical formula Ca{sub 1-x}Sr{sub x}Bi{sub 4}Ti{sub 4}O{sub 15} (CSBT) (x = 0.0-1.0) have been prepared through conventional solid state route. The formation of single phase material with orthorhombic structure was verified from X-ray diffraction with incorporation of Sr substitution. Decrease in a-axis displacement of Bi ion in the perovskite structure in the CSBT ceramics were observed from the relative changes in soft mode (20 cm{sup -1}) in the Raman spectra, and increase in Sr incorporation shows the shift in ferroelectric to paraelectric phase transition temperature. The dielectric properties for all the CSBT ceramic compositions are studied as a function of temperature over the frequency range of 100 Hz-1 MHz. Curie's temperature was found to be function of Sr substitution and with increase in the Sr concentration the phase transition becomes sharper and phase transition temperature gets shifted towards lower temperature (790-545 deg. C). The behavior of ac conductivity as a function of frequency (100 Hz-1 MHz) at low temperature (<500 deg. C) follows the power law and attributed to hopping conduction mechanism. Sr substitution results in the increase in piezoelectric coefficients (d{sub 33}) whereas piezoelectric charge coefficient values were found comparable to that of PZT at room temperature. Relative changes in soft modes due to Sr incorporation results in high piezoelectricity in the CSBT ceramics.

Surface-Selective Preferential Production of Reactive Oxygen Species on Piezoelectric Ceramics for Bacterial Killing.

Science.gov (United States)

Tan, Guoxin; Wang, Shuangying; Zhu, Ye; Zhou, Lei; Yu, Peng; Wang, Xiaolan; He, Tianrui; Chen, Junqi; Mao, Chuanbin; Ning, Chengyun

2016-09-21

Reactive oxygen species (ROS) can be used to kill bacterial cells, and thus the selective generation of ROS from material surfaces is an emerging direction in antibacterial material discovery. We found the polarization of piezoelectric ceramic causes the two sides of the disk to become positively and negatively charged, which translate into cathode and anode surfaces in an aqueous solution. Because of the microelectrolysis of water, ROS are preferentially formed on the cathode surface. Consequently, the bacteria are selectively killed on the cathode surface. However, the cell experiment suggested that the level of ROS is safe for normal mammalian cells.

Fabrication and performance of porous lithium sodium potassium niobate ceramic

Science.gov (United States)

Chen, Caifeng; Zhu, Yuan; Ji, Jun; Cai, Feixiang; Zhang, Youming; Zhang, Ningyi; Wang, Andong

2018-02-01

Porous lithium sodium potassium niobate (LNK) ceramic has excellent piezoelectric properties, chemical stability and great chemical compatibility. It has a good application potential in the field of biological bone substitute. In the paper, porous LNK ceramic was fabricated with egg albumen foaming agent by foaming method. Effects of preparation process of the porous LNK ceramic on density, phase structure, hole size and piezoelectric properties were researched and characterized. The results show that the influence factors of LNK solid content and foaming agent addition are closely relevant to properties of the porous LNK ceramic. When solid content is 65% and foaming agent addition is 30%, the porous LNK ceramic has uniform holes and the best piezoelectric properties.

Elution of lead from lead zirconate titanate ceramics to acid rain

Science.gov (United States)

Tsurumi, Takaaki; Takezawa, Shuhei; Hoshina, Takuya; Takeda, Hiroaki

2017-10-01

The amount of lead that eluted from lead zirconate titanate (PZT) ceramics to artificial acid rain was evaluated. Four kinds of PZT ceramics, namely, pure PZT at MPB composition, CuO-added PZT, PZT with 10 mol % substitution of Ba for Pb, and CuO-added PZT with 10 mol % substitution of Ba for Pb, were used as samples of the elution test. These PZT ceramics of 8 mm2 and 1.1-1.2 mm thickness were suspended in 300 ml of H2SO4 solution of pH 4.0. The concentration of lead eluted from PZT was in the range from 0.2 to 0.8 ppm. It was found that both liquid phase formation by the addition of CuO and the substitution of Ba for Pb were effective to reduce the amount of lead that eluted. By fitting the leaching out curve with a classical equation, a master curve assuming no sampling effect was obtained. The lead concentration evaluated from the amount of lead that eluted from a commercial PZT plate to H2SO4 solution of pH 5.3 was almost the same as the limit in city water. It is concluded that PZT is not harmful to health and the environment and the amount of lead that eluted from PZT can be controlled by modifying PZT composition.

Piezoelectric and mechanical properties of fatigue resistant, self-healing PZT-ionomer composites

Science.gov (United States)

James, N. K.; Lafont, U.; van der Zwaag, S.; Groen, W. A.

2014-05-01

Piezoelectric ceramic-polymer composites with 0-3 connectivity were fabricated using lead zirconium titanate (PZT) powder dispersed in an ionomer (Zn ionomer) and its reference ethylene methacrylic acid copolymer (EMAA) polymer matrix. The PZT-Zn ionomer and PZT-EMAA composites were prepared by melt extrusion followed by hot pressing. The effects of poling conditions such as temperature, time and electric field on the piezoelectric properties of the composites were investigated. The experimentally observed piezoelectric charge coefficient and dielectric constant of the composites were compared with theoretical models. The results show that PZT-Zn ionomer composites have better piezoelectric properties compared to PZT-EMAA composites. The static and fatigue properties of the composites were investigated. The PZT-Zn ionomer composites were found to have excellent fatigue resistance even at strain levels of 4%. Due to the self-healing capabilities of the ionomer matrix, the loss of piezoelectric properties after high strain tensile cyclic loading could be partially recovered by thermal healing.

Study of dielectric and piezoelectric properties of CNT reinforced PZT-PVA 0-3 composite

Science.gov (United States)

Vyas, Prince; Prajapat, Rampratap; Manmeeta, Saxena, Dhiraj

2016-05-01

Ferroelectric ceramic/polymer composites have the compliance of polymers which overcome the problems of brittleness in ceramics. By imbedding piezoelectric ceramic powder into a polymer matrix, 0-3 composites with good mechanical properties and high dielectric breakdown strength can be developed. The obtained composites of 0-3 connectivity exhibit the piezoelectric properties of ceramics and flexibility, strength and lightness of polymer. These composites can be used in vibration sensing and transducer applications specially as piezoelectric sensors. A potential way to improve piezoelectric& dielectric properties of theses composites is by inclusion of another conductive phase in these composites as reported in the literature. In present work, we prepared PZT-PVA 0-3 composites with 60% ceramic volume fraction reinforced with CNTs with volume ranging from 0 to 1.5 vol%. These CNT reinforced composites were obtained using hot press method with thickness of 200 µm having 0-3 conductivity. These composites were poled applying DC voltage. Dielectric properties of these samples were obtained in a wide frequency range (100 Hz to 1 Mhz) at room temperature. The piezoelectric properties of these composites were analyzed by measuring piezoelectric charge constants (d33). The dielectric and piezoelectric properties of these composites were studied as a function of CNT volume content. In these reinforced composites, CNTs act as a conductive filler dispersed in the matrix which in turn facilitates poling and results in an increase of the piezoelectric properties of the composite due to formation of percolation path through the composites. With a CNT content of 0.3 vol.% in PZT/PVA/CNTs, an increase of 61.3 % was observed in piezoelectric strain factors (d33). In these CNT reinforced composites, a substantial increase (approx. 67%) was also observed in dielectric constant and approximately 89% increase was observed in dielectric loss factor. Results so obtained are in the good

Effect of Ca2+ Ions on Electrical Properties of Ba1-x Ca x Ti0.90Sn0.10O3-0.05Y2O3 Ceramics

Science.gov (United States)

Chen, Zhi-hui; Li, Zhi-wei; Ding, Jian-ning; Zhao, Tian-xiang; Qiu, Jian-hua; Zhu, Ke-qian; Xu, Jiu-jun; Zhang, Bing

2018-03-01

Ba1-x Ca x Ti0.90Sn0.10O3-0.05Y2O3 (BCTSY) lead-free piezoceramics with x = 0.02 to 0.10 have been fabricated by solid-state sintering method at 1420°C. The effects of Ca2+ ions on the microstructure and electrical properties of the samples were studied. X-ray diffraction analysis showed that all samples possessed pure perovskite structure with Ca2+ ions diffused into the matrix lattice. The rhombohedral phase and tetragonal phase coexisted in the composition range of 0.02 ceramic became more homogeneous with addition of Ca2+ ions, and the average grain size of the samples decreased from 97 μm (x = 0.02) to 18 μm (x = 0.10). Addition of Ca2+ remarkably improved the piezoelectric properties, enhanced the dielectric frequency dispersion, and increased the Curie temperature of the ceramics. The piezoelectric properties of the ceramics were optimized at x = 0.04 with d 33 and K p values of 579 pC/N and 52.7%, respectively.

Dielectric, ferroelectric and piezoelectric properties of Nb{sup 5+} doped BCZT ceramics

Energy Technology Data Exchange (ETDEWEB)

Parjansri, Piewpan [Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, 50200 Chiang Mai (Thailand); Intatha, Uraiwan [School of Science, Mae Fah Luang University, 57100 Chiang Rai (Thailand); Eitssayeam, Sukum, E-mail: sukum99@yahoo.com [Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, 50200 Chiang Mai (Thailand); Materials Science Research Center, Faculty of Science, Chiang Mai University, 50200 Chiang Mai (Thailand)

2015-05-15

Highlights: • Average grain size of BCZT ceramic decreased with the increasing Nb{sup 5+} doping. • Dielectric constant value is enhanced with Nb{sup 5+} doping. • Dielectric loss of BCZT − x Nb{sup 5+} ceramics was less than 0.03 at room temperature (1 kHz). • Piezoelectric coefficient decreased with the increasing Nb{sup 5+} doping. • The relaxation behavior is enhanced with the doping of Nb{sup 5+}. - Abstract: This work investigated the electrical properties of Nb{sup 5+} (0.0–1.0 mol%) doped with Ba{sub 0.90}Ca{sub 0.10}Zr{sub 0.10}Ti{sub 0.90}O{sub 3} while adding 1 mol% of Ba{sub 0.90}Ca{sub 0.10}Zr{sub 0.10}Ti{sub 0.90}O{sub 3} seeds. The mixed powder was ball milled for 24 h, calcined and sintered at 1200 °C for 2 h and 1450 °C for 4 h, respectively. The XRD patterns of the ceramic samples were investigated by X-ray diffraction. The electrical properties of ceramics were measured and the results indicated that all samples show a pure perovskite phase with no secondary phase. Density and average grain size values were in the range of 5.60–5.71 g/cm{sup 3} and 12.62–1.86 μm, respectively. The highest dielectric constant, ϵ{sub r} at room temperature (1 kHz) was 4636 found at 1.0 mol% Nb. The dielectric loss, tan δ was less than 0.03 for all samples at room temperature (1 kHz). Other electrical properties, P{sub r}, d{sub 33} and k{sub p} values were decreased with Nb doped relates to the decreasing grain size in BCZT ceramics. Moreover, the degrees of phase transition diffuseness and relaxation behavior were observed in the higher Nb doping.

Development of ceramic-free antenna feeder

International Nuclear Information System (INIS)

Moriyama, S.; Kimura, H.; Fujii, T.; Saigusa, M.; Arai, H.

1994-01-01

We have proposed a ceramics-free antenna feeder line employing a ridged waveguide as a local support for IC antenna of next-generation tokamaks. One fourth mock-up model of the all metal waveguide designed for the ITER ICRF system is fabricated and electrical characteristics of the model including the coaxial line - waveguide converter are measured. Power reflection coefficient of the model including the coax-waveguide converter to the input coaxial line is estimated to be less than 15% below the cut-off frequency of 107 MHz and less than 3% above the cut-off frequency. It is found that this ceramics-free antenna support employing a ridged waveguide is quite available for IC antenna of next-generation tokamaks. (author)

Childhood Blood Lead Reductions Following Removal of Leaded Ceramic Glazes in Artisanal Pottery Production: A Success Story

OpenAIRE

Donald E. Jones, MS; Mario Covarrubias Pérez; Bret Ericson; Daniel Estrada Sánchez; Sandra Gualtero; Andrea Smith-Jones, MS; Jack Caravanos, DrPH, CIH

2013-01-01

Background. Lead exposure within artisanal ceramics workshop communities in Mexico continues to be a major source of childhood lead poisoning. Artisanal ceramics workshops expose children through direct ingestion, contaminated soil, and food prepared in lead-glazed pottery. Conversion to non-lead glazes alone may not effectively reduce exposure. This paper describes a model comprehensive intervention and environmental remediation of an artisanal ceramics workshop in the state of Hidalgo, Mexi...

Preparation and properties of porous PMN-PZT ceramics doped with strontium

International Nuclear Information System (INIS)

Zeng Tao; Dong Xianlin; Mao Chaoliang; Chen Shutao; Chen Heng

2006-01-01

The piezoelectric and dielectric properties of lead magnesium niobate-lead zirconate titanate (PMN-PZT) ceramics were investigated as a function of density for transducer applications. A decrease in density increased elastic compliance and improved acoustic impedance matching between PMN-PZT ceramics and ambient media. The reduced dielectric constant (ε 33 ) and enhanced hydrostatic figure of merit (d h g h ) of PMN-PZT were observed with decreased density. The results showed the d h g h of PMN-PZT ceramic with density of about 5.4 g/cm 3 reached 4000 x 10 -15 m 2 /N, and the ε 33 was very close to 2000, which demonstrates that porous PMN-PZT ceramic is a promising material for transducer applications. Moreover, the low density PMN-PZT ceramics exhibited lower dielectric loss than high density PMN-PZT ceramics during the temperature from 250 deg. C to 500 deg. C

Piezoelectric Transformers: An Historical Review

Directory of Open Access Journals (Sweden)

Alfredo Vazquez Carazo

2016-04-01

Full Text Available Piezoelectric transformers (PTs are solid-state devices that transform electrical energy into electrical energy by means of a mechanical vibration. These devices are manufactured using piezoelectric materials that are driven at resonance. With appropriate design and circuitry, it is possible to step up and step down the voltages between the input and output sections of the piezoelectric transformer, without making use of magnetic materials and obtaining excellent conversion efficiencies. The initial concept of a piezoelectric ceramic transformer was proposed by Charles A. Rosen in 1954. Since then, the evolution of piezoelectric transformers through history has been linked to the relevant work of some excellent researchers as well as to the evolution in materials, manufacturing processes, and driving circuit techniques. This paper summarizes the historical evolution of the technology.

Characteristics of 1–3-type ferroelectric ceramic/auxetic polymer composites

International Nuclear Information System (INIS)

Topolov, V Yu; Bowen, C R

2008-01-01

This paper presents modelling and simulation results on 1–3 piezoactive composites comprising a range of ferroelectric ceramics, which are assumed to have variable properties and an auxetic polymer (i.e. a material with a negative Poisson ratio) that improves the hydrostatic piezoelectric response of the composite. Dependences of the effective piezoelectric coefficients and related parameters of the 1–3 composites on the degree of poling, mobility of the 90° domain walls within ceramic grains, on the volume fraction of the ceramic component and on the Poisson ratio of the polymer component have been calculated and analysed. The role of the piezoelectric anisotropy and domain-orientation processes in improving and optimising the effective parameters, piezoelectric activity and sensitivity of 1–3 ferroelectric ceramic/auxetic composites is discussed

Piezoelectric ceramic (PZT) modulates axonal guidance growth of rat cortical neurons via RhoA, Rac1, and Cdc42 pathways.

Science.gov (United States)

Wen, Jianqiang; Liu, Meili

2014-03-01

Electrical stimulation is critical for axonal connection, which can stimulate axonal migration and deformation to promote axonal growth in the nervous system. Netrin-1, an axonal guidance cue, can also promote axonal guidance growth, but the molecular mechanism of axonal guidance growth under indirect electric stimulation is still unknown. We investigated the molecular mechanism of axonal guidance growth under piezoelectric ceramic lead zirconate titanate (PZT) stimulation in the primary cultured cortical neurons. PZT induced marked axonal elongation. Moreover, PZT activated the excitatory postsynaptic currents (EPSCs) by increasing the frequency and amplitude of EPSCs of the cortical neurons in patch clamp assay. PZT downregulated the expression of Netrin-1 and its receptor Deleted in Colorectal Cancer (DCC). Rho GTPase signaling is involved in interactions of Netrin-1 and DCC. PZT activated RhoA. Dramatic decrease of Cdc42 and Rac1 was also observed after PZT treatment. RhoA inhibitor Clostridium botulinum C3 exoenzyme (C3-Exo) prevented the PZT-induced downregulation of Netrin-1 and DCC. We suggest that PZT can promote axonal guidance growth by downregulation of Netrin-1 and DCC to mediate axonal repulsive responses via the Rho GTPase signaling pathway. Obviously, piezoelectric materials may provide a new approach for axonal recovery and be beneficial for clinical therapy in the future.

Piezoelectric Flexible LCP-PZT Composites for Sensor Applications at Elevated Temperatures

Science.gov (United States)

Tolvanen, Jarkko; Hannu, Jari; Juuti, Jari; Jantunen, Heli

2018-03-01

In this paper fabrication of piezoelectric ceramic-polymer composites is demonstrated via filament extrusion enabling cost-efficient large-scale production of highly bendable pressure sensors feasible for elevated temperatures. These composites are fabricated by utilizing environmentally resistant and stable liquid crystal polymer matrix with addition of lead zirconate titanate at loading levels of 30 vol%. These composites, of approximately 0.99 mm thick and length of > 50 cm, achieved excellent bendability with minimum bending radius of 6.6 cm. The maximum piezoelectric coefficients d33 and g33 of the composites were > 14 pC/N and > 108 mVm/N at pressure < 10 kPa. In all cases, the piezoelectric charge coefficient (d33) of the composites decreased as a function of pressure. Also, piezoelectric coefficient (d33) further decreased in the case of increased frequency press-release cycle sand pre-stress levels by approximately 37-50%. However, the obtained results provide tools for fabricating novel piezoelectric sensors in highly efficient way for environments with elevated temperatures.

Comparison of the properties of tonpilz transducers fabricated with 001 fiber-textured lead magnesium niobate-lead titanate ceramic and single crystals.

Science.gov (United States)

Brosnan, Kristen H; Messing, Gary L; Markley, Douglas C; Meyer, Richard J

2009-11-01

Tonpilz transducers are fabricated from 001 fiber-textured 0.72Pb(Mg(1/3)Nb(2/3))O(3)-0.28PbTiO(3) (PMN-28PT) ceramics, obtained by the templated grain growth process, and PMN-28PT ceramic and Bridgman grown single crystals of the same composition. In-water characterization of single element transducers shows higher source levels, higher in-water coupling, and more usable bandwidth for the 81 vol % textured PMN-28PT device than for the ceramic PMN-28PT element. The 81 vol % textured PMN-28PT tonpilz element measured under large signals shows linearity in sound pressure levels up to 0.23 MV/m drive field but undergoes a phase transition due to a lowered transition temperature from the SrTiO(3) template particles. Although the textured ceramic performs well in this application, it could be further improved with compositional tailoring to raise the transition temperature and better processing to improve the texture quality. With these improvements textured piezoelectric ceramics will be viable options for medical ultrasound, actuators, and sonar applications because of their ease of processing, compositional homogeneity, and potentially lower cost than single crystal.

Structural, dielectric and piezoelectric study of Ca-, Zr-modified ...

Indian Academy of Sciences (India)

2017-08-22

Aug 22, 2017 ... Ferroelectric materials have attracted the attention of researchers around .... and piezoelectric properties than the BCTZ ceramics with finer grains but .... to the polycrys- tallinity and the porosity of the textured BCTZ ceramics.

Enhancement of the piezoelectric properties of sodium lanthanum bismuth titanate (Na0.5La0.5Bi4Ti4O15) through modification with cobalt

International Nuclear Information System (INIS)

Wang Chunming; Wang Jinfeng; Zheng Limei; Zhao Minglei; Wang Chunlei

2010-01-01

The dielectric, piezoelectric, and electromechanical properties of B-site cobalt-modified sodium lanthanum bismuth titanate (Na 0.5 La 0.5 Bi 4 Ti 4 O 15 , NLBT) piezoelectric ceramics were investigated. The piezoelectric properties of NLBT ceramics can be enhanced by cobalt modifications. The NLBT ceramics modified with 0.2 wt.% cobalt trioxide (NLBT-C4) possess good piezoelectric properties, with piezoelectric coefficient d 33 of 27 pC/N, electromechanical coupling factors (k p and k t ) of 6.5% and 28.5%, and mechanical quality factor Q m (k p mode) of 3400. The Curie temperature T c of cobalt-modified NLBT ceramics was found to slightly higher than that of pure NLBT ceramics. A large dielectric abnormity in dielectric loss tan δ was observed in NLBT ceramics, which can be significantly suppressed by cobalt modification. Thermal annealing studies presented the cobalt-modified NLBT ceramics possess stable piezoelectric properties.

A review on one dimensional perovskite nanocrystals for piezoelectric applications

Directory of Open Access Journals (Sweden)

Li-Qian Cheng

2016-03-01

Full Text Available In recent years, one-dimensional piezoelectric nanomaterials have become a research topic of interest because of their special morphology and excellent piezoelectric properties. This article presents a short review on one dimensional perovskite piezoelectric materials in different systems including Pb(Zr,TiO3, BaTiO3 and (K,NaNbO3 (KNN. We emphasize KNN as a promising lead-free piezoelectric compound with a high Curie temperature and high piezoelectric properties and describe its synthesis and characterization. In particular, details are presented for nanoscale piezoelectricity characterization of a single KNN nanocrystal by piezoresponse force microscopy. Finally, this review describes recent progress in applications based on one dimensional piezoelectric nanostructures with a focus on energy harvesting composite materials.

Texturing of sodium bismuth titanate-barium titanate ceramics by templated grain growth

Science.gov (United States)

Yilmaz, Huseyin

2002-01-01

Sodium bismuth titanate modified with barium titanate, (Na1/2Bi 1/2)TiO3-BaTiO3 (NBT-BT), is a candidate lead-free piezoelectric material which has been shown to have comparatively high piezoelectric response. In this work, textured (Na1/2Bi1/2)TiO 3-BaTiO3 (5.5mol% BaTiO3) ceramics with pc (where pc denotes the pseudocubic perovskite cell) orientation were fabricated by Templated Grain Growth (TGG) or Reactive Templated Grain Growth (RTGG) using anisotropically shaped template particles. In the case of TGG, molten salt synthesized SrTiO3 platelets were tape cast with a (Na1/2Bi1/2)TiO3-5.5mol%BaTiO3 powder and sintered at 1200°C for up to 12 hours. For the RTGG approach, Bi4Ti3O12 (BiT) platelets were tape cast with a Na2CO3, Bi2O3, TiO 2, and BaCO3 powder mixture and reactively sintered. The TGG approach using SrTiO3 templates gave stronger texture along [001] compared to the RTGG approach using BiT templates. The textured ceramics were characterized by X-ray and electron backscatter diffraction for the quality of texture. The texture function was quantified by the Lotgering factor, rocking curve, pole figures, inverse pole figures, and orientation imaging microscopy. Electrical and electromechanical property characterization of randomly oriented and pc textured (Na1/2Bi1/2)TiO 3-5.5 mol% BaTiO3 rhombohedral ceramics showed 0.26% strain at 70 kV/cm, d33 coefficients over 500 pC/N have been obtained for highly textured samples (f ˜ 90%). The piezoelectric coefficient from Berlincourt was d33 ˜ 200 pC/N. The materials show considerable hysteresis. The presence of hysteresis in the unipolar-electric field curve is probably linked to the ferroelastic phase transition seen in the (Na 1/2Bi1/2)TiO3 system on cooling from high temperature at ˜520°C. The macroscopic physical properties (remanent polarization, dielectric constant, and piezoelectric coefficient) of random and textured ([001] pc) rhombohedral perovskites were estimated by linear averaging of single

An Assessment of New Applications for Single-Crystal Piezoelectric Materials

National Research Council Canada - National Science Library

Veitch, Lisa

1998-01-01

Piezoelectricity was first discovered by the Curie brothers in 1880. During the 1940s, piezoelectric ceramic materials were first used in commercial devices, and new materials and other applications have continued to develop over the years...

Fractal cluster modeling of the fatigue behavior of lead zirconate titanate

OpenAIRE

Priya, Shashank; Kim, Hyeoung Woo; Ryu, Jungho; Uchino, Kenji; Viehland, Dwight D.

2002-01-01

The fatigue behavior of lead zirconate titanate ceramics (PZT) has been studied under electrical and mechanical drives. Piezoelectric fatigue was studied using a mechanical method. Under ac mechanical drive, hard and soft PZTs showed an increase in the longitudinal piezoelectric constant at short times, reaching a maximum at intermediate times. Systematic investigations were performed to characterize the electrical fatigue behavior. A decrease in the magnitude of the remanent polarization was...

Piezoelectric potential gated field-effect transistor based on a free-standing ZnO wire.

Science.gov (United States)

Fei, Peng; Yeh, Ping-Hung; Zhou, Jun; Xu, Sheng; Gao, Yifan; Song, Jinhui; Gu, Yudong; Huang, Yanyi; Wang, Zhong Lin

2009-10-01

We report an external force triggered field-effect transistor based on a free-standing piezoelectric fine wire (PFW). The device consists of an Ag source electrode and an Au drain electrode at two ends of a ZnO PFW, which were separated by an insulating polydimethylsiloxane (PDMS) thin layer. The working principle of the sensor is proposed based on the piezoelectric potential gating effect. Once subjected to a mechanical impact, the bent ZnO PFW cantilever creates a piezoelectric potential distribution across it width at its root and simultaneously produces a local reverse depletion layer with much higher donor concentration than normal, which can dramatically change the current flowing from the source electrode to drain electrode when the device is under a fixed voltage bias. Due to the free-standing structure of the sensor device, it has a prompt response time less than 20 ms and quite high and stable sensitivity of 2%/microN. The effect from contact resistance has been ruled out.

Cryogenic Rotary Piezoelectric Motor, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — Piezoelectric motors operate on the principal of converting the high-frequency oscillation of high-force, precision ceramic elements into useful continuous motion....

Fabrication of crystal-oriented barium-bismuth titanate ceramics in high magnetic field and subsequent reaction sintering

International Nuclear Information System (INIS)

Tanaka, Satoshi; Tomita, Yusuke; Furushima, Ryoichi; Uematsu, Keizo; Shimizu, Hiroyuki; Doshida, Yutaka

2009-01-01

High magnetic field was applied to fabricate novel lead-free piezoelectric ceramics with a textured structure. A compact of crystallographically oriented grains was prepared by dry forming in a high magnetic field from a mixed slurry of bismuth titanate and barium titanate powders. Bismuth titanate particles with a size of about 1 μ m were used as the host material. In the forming process, the slurry was poured into a mold and set in a magnetic field of 10 T until completely dried. Bismuth titanate particles were highly oriented in the slurry under the magnetic field. The dried powder compact consisted of highly oriented bismuth titanate particles and randomly oriented barium titanate particles. Barium bismuth titanate ceramics with a- and b-axis orientations were successfully produced from the dried compact by sintering at temperatures above 1100 deg. C.

Structural, microstructural, dielectric and ferroelectric properties of lead free Ba0.85Ca0.15Zr0.1Ti0.9O3 ceramic

Science.gov (United States)

Sharma, Sarita; Sharma, Hakikat; Negi, N. S.

2018-05-01

Lead free Ba0.85Ca0.15Zr0.1Ti0.9O3(BCTZ) ceramic has been synthesized by sol-gel method. Properties of material are studied at different sintering temperatures for 5 hours. Structural and microstructural properties are analyzed by using X-ray diffractrometer (XRD) and scanning electron microscopy (SEM) at annealing temperature of 850°C and 1050°C XRD pattern confirm the perovskite structure of the material without any unwanted phases crystalinity increased with increase of sintering temperature so as roughness and porosity is decreased as shown by SEM micrographs. There is large improvement in density with rise of sintering temperature which also leads to drastic change in ferroelectric and dielectric properties.

Cryogenic Rotary Piezoelectric Motor, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — Piezoelectric motors operate on the principal of high frequency oscillation of high force precision ceramic elements. The high power oscillations are converted to...

Switchable static friction of piezoelectric composite-silicon wafer contacts

NARCIS (Netherlands)

Ende, D.A. van den; Fischer, H.R.; Groen, W.A.; Zwaag, S. van der

2013-01-01

The meso-scale surface roughness of piezoelectric fiber composites can be manipulated by applying an electric field to a piezocomposite with a polished surface. In the absence of an applied voltage, the tips of the embedded piezoelectric ceramic fibers are below the surface of the piezocomposite and

Switchable static friction of piezoelectric composite—silicon wafer contacts

NARCIS (Netherlands)

Van den Ende, D.A.; Fischer, H.R.; Groen, W.A.; Van der Zwaag, S.

2013-01-01

The meso-scale surface roughness of piezoelectric fiber composites can be manipulated by applying an electric field to a piezocomposite with a polished surface. In the absence of an applied voltage, the tips of the embedded piezoelectric ceramic fibers are below the surface of the piezocomposite and

Development of piezoelectric ceramics driven fatigue testing machine for small specimens

International Nuclear Information System (INIS)

Saito, S.; Kikuchi, K.; Onishi, Y.; Nishino, T.

2002-01-01

A new fatigue testing machine with piezoelectric ceramics actuators was developed and a prototype was manufactured for high-cycle fatigue tests with small specimens. The machine has a simple mechanism and is compact. These features make it easy to set up and to maintain the machine in a hot cell. The excitation of the actuator can be transmitted to the specimen using a lever-type testing jig. More than 100 μm of displacement could be prescribed precisely to the specimen at a frequency of 50 Hz. This was sufficient performance for high-cycle bend fatigue tests on specimens irradiated at the SINQ target in Paul Scherrer Institute. The relationship of a displacement applied to the specimen and the strain of the necking part were obtained by experimental methods and by finite element method (FEM) calculations. Both results showed good agreement. This fact makes it possible to evaluate the strain of irradiated specimens by FEM simulations

Compact piezoelectric micromotor with a single bulk lead zirconate titanate stator

Science.gov (United States)

Yan, Liang; Lan, Hua; Jiao, Zongxia; Chen, Chin-Yin; Chen, I.-Ming

2013-04-01

The advance of micro/nanotechnology promotes the development of micromotors in recent years. In this article, a compact piezoelectric ultrasonic micromotor with a single bulk lead zirconate titanate stator is proposed. A traveling wave is generated by superposition of bending modes with 90° phase difference excited by d15 inverse piezoelectric effects. The operating principle simplifies the system structure significantly, and provides a miniaturization solution. A research prototype with the size of 0.75× 0.75×1.55 mm is developed. It can produce start-up torque of 0.27μNmand maximum speed of 2760 r/min at 14RMS.

Power harvesting using PZT ceramics embedded in orthopedic implants.

Science.gov (United States)

Chen, Hong; Liu, Ming; Jia, Chen; Wang, Zihua

2009-09-01

Battery lifetime has been the stumbling block for many power-critical or maintenance-free real-time embedded applications, such as wireless sensors and orthopedic implants. Thus a piezoelectric material that could convert human motion into electrical energy provides a very attractive solution for clinical implants. In this work, we analyze the power generation characteristics of stiff lead zirconate titanate (PZT) ceramics and the equivalent circuit through extensive experiments. Our experimental framework allows us to explore many important design considerations of such a PZT-based power generator. Overall we can achieve a PZT element volume of 0.5 x 0.5 x 1.8 cm, which is considerably smaller than the results reported so far. Finally, we outline the application of our PZT elements in a total knee replacement (TKR) implant.

Microstructure of lead zirconium titanate (PZT) by electron microscopy

International Nuclear Information System (INIS)

Bursill, L.A.; Peng JuLin

1989-01-01

Transmission and high-resolution electron microscopy reveal the microtexture of lead zirconium titanate ceramics. Fine scale (≤ 500 Aangstroem) ferroelastic and ferroelectric twin domains, as well as dislocations were found in a complex texture. Correlations between stoichiometry, microstructure and piezoelectric properties are discussed. 6 refs., 3 figs

Study on the piezoelectric behavior and structural changes of strontium doped PZT

International Nuclear Information System (INIS)

Silva, M.S. da; Lemos, L.; Souza, E.F.; Cavalheiro, A.A.; Longo, E.; Zaghete, M.A.

2014-01-01

Lead zirconate titanate, with Zr/Ti ratio of 53/47 was prepared by the polymeric precursor method. The powders were doped with 0.0, 0.2, 0.4 and 0.6 mol% of Sr 2+ and the effects of Sr 2+ additions on piezoelectric properties and on the phase constitution were investigated by XRD. The percentages of tetragonal and rhombohedral phases were calculated through Rietveld refinement. The results indicated that addition of Sr 2+ ions in the amount of 0.4 mol% in the ceramic structure maximally increase the values of piezoelectric parameter to d 33 = 289 μC/N and K p = 0.43. The values found for the piezoelectric properties were among the highest at the concentration of 0.4 mol% of strontium and this composition showed the highest structural change from the rhombohedral to the tetragonal phase perovskita. (author)

Stretchable piezoelectric nanocomposite generator.

Science.gov (United States)

Park, Kwi-Il; Jeong, Chang Kyu; Kim, Na Kyung; Lee, Keon Jae

2016-01-01

Piezoelectric energy conversion that generate electric energy from ambient mechanical and vibrational movements is promising energy harvesting technology because it can use more accessible energy resources than other renewable natural energy. In particular, flexible and stretchable piezoelectric energy harvesters which can harvest the tiny biomechanical motions inside human body into electricity properly facilitate not only the self-powered energy system for flexible and wearable electronics but also sensitive piezoelectric sensors for motion detectors and in vivo diagnosis kits. Since the piezoelectric ZnO nanowires (NWs)-based energy harvesters (nanogenerators) were proposed in 2006, many researchers have attempted the nanogenerator by using the various fabrication process such as nanowire growth, electrospinning, and transfer techniques with piezoelectric materials including polyvinylidene fluoride (PVDF) polymer and perovskite ceramics. In 2012, the composite-based nanogenerators were developed using simple, low-cost, and scalable methods to overcome the significant issues with previously-reported energy harvester, such as insufficient output performance and size limitation. This review paper provides a brief overview of flexible and stretchable piezoelectric nanocomposite generator for realizing the self-powered energy system with development history, power performance, and applications.

Fabrication and in vitro biological properties of piezoelectric bioceramics for bone regeneration

Science.gov (United States)

Tang, Yufei; Wu, Cong; Wu, Zixiang; Hu, Long; Zhang, Wei; Zhao, Kang

2017-02-01

The piezoelectric effect of biological piezoelectric materials promotes bone growth. However, the material should be subjected to stress before it can produce an electric charge that promotes bone repair and reconstruction conducive to fracture healing. A novel method for in vitro experimentation of biological piezoelectric materials with physiological load is presented. A dynamic loading device that can simulate the force of human motion and provide periodic load to piezoelectric materials when co-cultured with cells was designed to obtain a realistic expression of piezoelectric effect on bone repair. Hydroxyapatite (HA)/barium titanate (BaTiO3) composite materials were fabricated by slip casting, and their piezoelectric properties were obtained by polarization. The d33 of HA/BaTiO3 piezoelectric ceramics after polarization was 1.3 pC/N to 6.8 pC/N with BaTiO3 content ranging from 80% to 100%. The in vitro biological properties of piezoelectric bioceramics with and without cycle loading were investigated. When HA/BaTiO3 piezoelectric bioceramics were affected by cycle loading, the piezoelectric effect of BaTiO3 promoted the growth of osteoblasts and interaction with HA, which was better than the effect of HA alone. The best biocompatibility and bone-inducing activity were demonstrated by the 10%HA/90%BaTiO3 piezoelectric ceramics.

Polarization Switching and Light-Enhanced Piezoelectricity in Lead Halide Perovskites.

Science.gov (United States)

Coll, Mariona; Gomez, Andrés; Mas-Marza, Elena; Almora, Osbel; Garcia-Belmonte, Germà; Campoy-Quiles, Mariano; Bisquert, Juan

2015-04-16

We investigate the ferroelectric properties of photovoltaic methylammonium lead halide CH3NH3PbI3 perovskite using piezoelectric force microscopy (PFM) and macroscopic polarization methods. The electric polarization is clearly observed by amplitude and phase hysteresis loops. However, the polarization loop decreases as the frequency is lowered, persisting for a short time only, in the one second regime, indicating that CH3NH3PbI3 does not exhibit permanent polarization at room temperature. This result is confirmed by macroscopic polarization measurement based on a standard capacitive method. We have observed a strong increase of piezoelectric response under illumination, consistent with the previously reported giant photoinduced dielectric constant at low frequencies. We speculate that an intrinsic charge transfer photoinduced dipole in the perovskite cage may lie at the origin of this effect.

Piezoelectric ultrasonic micromotor with 1.5 mm diameter.

Science.gov (United States)

Dong, Shuxiang; Lim, Siak P; Lee, Kwork H; Zhang, Jingdong; Lim, Leong C; Uchino, Kenji

2003-04-01

A piezoelectric ultrasonic micromotor has been developed using a lead zirconate titanate (PZT) ceramic/metal composite tube stator that was 1.5 mm in diameter and 7 mm in length. The micromotor was operated in its first bending vibration mode (approximately 70 kHz), producing speeds from hundreds to over 2000 rpm in both rotational directions. The maximum torque-output was 45 microN-m, which is far superior to previous PZT thin film-based micromotors. This micromotor showed good reliability and stability for more than 300 hours of continued operation.

Synthesis of 0.64Pb(Mg1/3Nb2/3O3–0.36PbTiO3 ceramic near morphotropic phase boundary for high performance piezoelectric, ferroelectric and pyroelectric applications

Directory of Open Access Journals (Sweden)

Abid Hussain

2016-09-01

Full Text Available A near MPB composition of 0.64PMN–0.36PT ceramic has been synthesized by solid-state reaction technique using columbite precursor. Sintering at 1030 °C resulted in a single perovskite phase with tetragonal structure having uniform and dense microstructure as revealed by powder XRD, Raman spectroscopy and FESEM analyses. An excellent dielectric response was obtained with room temperature dielectric permittivity value of 142 and high-phase transition temperature (Tm of 210 °C at 1 kHz. A huge value of piezoelectric charge coefficient (490 pC/N was obtained, which shows potential of PMN–PT for piezoelectric device applications. Well-shaped and fatigue-free P–E hysteresis loops over a wide temperature range of 30–230 °C were traced. A very large value of pyroelectric coefficient (p ∼ 2739.2 μC m−2 °C−1 was obtained.

Design and analysis of a piezoelectric material based touch screen with additional pressure and its acceleration measurement functions

International Nuclear Information System (INIS)

Chu, Xiang-Cheng; Liu, Jia-Yi; Gao, Ren-Long; Chang, Jie; Li, Long-Tu

2013-01-01

Touch screens are becoming more and more prevalent in everyday environments due to their convenience and humanized operation. In this paper, a piezoelectric material based touch screen is developed and investigated. Piezoelectric ceramics arrayed under the touch panel at the edges or corners are used as tactile sensors to measure the touch positioning point similarly to conventional touch screens. However, additional touch pressure and its acceleration performance can also be obtained to obtain a higher-level human–machine interface. The piezoelectric ceramics can also be added to a traditional touch screen structure, or they can be used independently to construct a novel touch screen with a high light transmittance approach to a transparent glass. The piezoelectric ceramics were processed from PZT piezoelectric ceramic powder into a round or rectangular shape. According to the varied touch position and physical press strength of a finger, or even a gloved hand or fingernail, the piezoelectric tactile sensors will have different output voltage responses. By calculating the ratio of different piezoelectric tactile sensors’ responses and summing up all piezoelectric tactile sensors’ output voltages, the touch point position, touch pressure and touch force acceleration can be detected. A prototype of such a touch screen is manufactured and its position accuracy, touch pressure and response speed are measured in detail. The experimental results show that the prototype has many advantages such as high light transmittance, low energy cost and high durability. (paper)

Domain wall motion and electromechanical strain in lead-free piezoelectrics: Insight from the model system (1 − x)Ba(Zr{sub 0.2}Ti{sub 0.8})O{sub 3}–x(Ba{sub 0.7}Ca{sub 0.3})TiO{sub 3} using in situ high-energy X-ray diffraction during application of electric fields

Energy Technology Data Exchange (ETDEWEB)

Tutuncu, Goknur [Department of Materials Science and Engineering, University of Florida, Gainesville, Florida 32611 (United States); Li, Binzhi [Department of Chemical Engineering and Materials Science, University of California, Davis, Davis, California 95616 (United States); Bowman, Keith [Illinois Institute of Technology, Armour College of Engineering, Chicago, Illinois 60616 (United States); School of Materials Engineering, Purdue University, West Lafayette, Indiana 47907 (United States); Jones, Jacob L., E-mail: JacobJones@ncsu.edu [Department of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695 (United States)

2014-04-14

The piezoelectric compositions (1 − x)Ba(Zr{sub 0.2}Ti{sub 0.8})O{sub 3}–x(Ba{sub 0.7}Ca{sub 0.3})TiO{sub 3} (BZT-xBCT) span a model lead-free morphotropic phase boundary (MPB) between room temperature rhombohedral and tetragonal phases at approximately x = 0.5. In the present work, in situ X-ray diffraction measurements during electric field application are used to elucidate the origin of electromechanical strain in several compositions spanning the tetragonal compositional range 0.6 ≤ x ≤ 0.9. As BCT concentration decreases towards the MPB, the tetragonal distortion (given by c/a-1) decreases concomitantly with an increase in 90° domain wall motion. The increase in observed macroscopic strain is predominantly attributed to the increased contribution from 90° domain wall motion. The results demonstrate that domain wall motion is a significant factor in achieving high strain and piezoelectric coefficients in lead-free polycrystalline piezoelectrics.

Conventional and two step sintering of PZT-PCN ceramics

Science.gov (United States)

Keshavarzi, Mostafa; Rahmani, Hooman; Nemati, Ali; Hashemi, Mahdieh

2018-02-01

In this study, PZT-PCN ceramic was made via sol-gel seeding method and effects of conventional sintering (CS) as well as two-step sintering (TSS) were investigated on microstructure, phase formation, density, dielectric and piezoelectric properties. First, high quality powder was achieved by seeding method in which the mixture of Co3O4 and Nb2O5 powder was added to the prepared PZT sol to form PZT-PCN gel. After drying and calcination, pyrochlore free PZT-PCN powder was synthesized. Second, CS and TSS were applied to achieve dense ceramic. The optimum temperature used for 2 h of conventional sintering was obtained at 1150 °C; finally, undesired ZrO2 phase formed in CS procedure was removed successfully with TSS procedure and dielectric and piezoelectric properties were improved compared to the CS procedure. The best electrical properties obtained for the sample sintered by TSS in the initial temperature of T 1 = 1200 °C and secondary temperature of T 2 = 1000 °C for 12 h.

Piezoelectric properties and unipolar fatigue behavior of KNN-based Pb-free piezoceramics.

Science.gov (United States)

Patterson, Eric A; Cann, David P

2011-09-01

Single-phase perovskite ceramics were synthesized using a Pb-free (K(0.44)Na(0.52)Li(0.04))(Nb(0.86)Ta(0.10)Sb(0.04))O(3) (LF4) piezoelectric material both with and without CuO as a dopant additive. Bipolar hysteresis measurements showed a relatively high remanent polarization (20 μC/cm(2), 16 μC/cm(2)) and maximum polarization (25 μC/cm(2), 21 μC/cm(2)) values were found for undoped LF4 and 0.2 wt% CuO-doped LF4, respectively. Unipolar fatigue behavior for this system was found to decrease strongly with increased applied testing fields and increased test durations. For undoped LF4, the maximum polarization values were stable after 10 cycles after testing for 100,000 cycles duration. For the CuO-doped samples, increasing the testing field to 3E(C) resulted in twice the decrease in P(MAX) (¿32%) compared with the 2E(C) tests at 10(6) cycles (-17%). At 2E(C) testing for CuO doping, polarization decreases continually through 10(7) cycles, with the decreases in P(MAX) and d(33) both reaching a maximum (-22% and -30%, respectively) after 10(7) cycles. In the CuO-doped samples, the fatigue is exacerbated because of the influence of space charge on the increased number of defects present.

Fabrication of Lead-Free Bi0.5Na0.5TiO3 Thin Films by Aqueous Chemical Solution Deposition

Directory of Open Access Journals (Sweden)

Mads Christensen

2017-02-01

Full Text Available Piezoelectric ceramics are widely used in actuator applications, and currently the vast majority of these devices are based on Pb ( Zr , Ti O 3 , which constitutes environmental and health hazards due to the toxicity of lead. One of the most promising lead-free material systems for actuators is based on Bi 0 . 5 Na 0 . 5 TiO 3 (BNT, and here we report on successful fabrication of BNT thin films by aqueous chemical solution deposition. The precursor solution used in the synthesis is based on bismuth citrate stabilized by ethanolamine, NaOH , and a Ti-citrate prepared from titanium tetraisopropoxide and citric acid. BNT thin films were deposited on SrTiO 3 and platinized silicon substrates by spin-coating, and the films were pyrolized and annealed by rapid thermal processing. The BNT perovskite phase formed after calcination at 500 °C in air. The deposited thin films were single phase according to X-ray diffraction, and the microstructures of the films shown by electron microscopy were homogeneous and dense. Decomposition of the gel was thoroughly investigated, and the conditions resulting in phase pure materials were identified. This new aqueous deposition route is low cost, robust, and suitable for development of BNT based thin film for actuator applications.

Unexpectedly high piezoelectricity of Sm-doped lead zirconate titanate in the Curie point region.

Science.gov (United States)

Seshadri, Shruti B; Nolan, Michelle M; Tutuncu, Goknur; Forrester, Jennifer S; Sapper, Eva; Esteves, Giovanni; Granzow, Torsten; Thomas, Pam A; Nino, Juan C; Rojac, Tadej; Jones, Jacob L

2018-03-07

Large piezoelectric coefficients in polycrystalline lead zirconate titanate (PZT) are traditionally achieved through compositional design using a combination of chemical substitution with a donor dopant and adjustment of the zirconium to titanium compositional ratio to meet the morphotropic phase boundary (MPB). In this work, a different route to large piezoelectricity is demonstrated. Results reveal unexpectedly high piezoelectric coefficients at elevated temperatures and compositions far from the MPB. At temperatures near the Curie point, doping with 2 at% Sm results in exceptionally large piezoelectric coefficients of up to 915 pm/V. This value is approximately twice those of other donor dopants (e.g., 477 pm/V for Nb and 435 pm/V for La). Structural changes during the phase transitions of Sm-doped PZT show a pseudo-cubic phase forming ≈50 °C below the Curie temperature. Possible origins of these effects are discussed and the high piezoelectricity is posited to be due to extrinsic effects. The enhancement of the mechanism at elevated temperatures is attributed to the coexistence of tetragonal and pseudo-cubic phases, which enables strain accommodation during electromechanical deformation and interphase boundary motion. This work provides insight into possible routes for designing high performance piezoelectrics which are alternatives to traditional methods relying on MPB compositions.

High Temperature, High Power Piezoelectric Composite Transducers

Science.gov (United States)

Lee, Hyeong Jae; Zhang, Shujun; Bar-Cohen, Yoseph; Sherrit, StewarT.

2014-01-01

Piezoelectric composites are a class of functional materials consisting of piezoelectric active materials and non-piezoelectric passive polymers, mechanically attached together to form different connectivities. These composites have several advantages compared to conventional piezoelectric ceramics and polymers, including improved electromechanical properties, mechanical flexibility and the ability to tailor properties by using several different connectivity patterns. These advantages have led to the improvement of overall transducer performance, such as transducer sensitivity and bandwidth, resulting in rapid implementation of piezoelectric composites in medical imaging ultrasounds and other acoustic transducers. Recently, new piezoelectric composite transducers have been developed with optimized composite components that have improved thermal stability and mechanical quality factors, making them promising candidates for high temperature, high power transducer applications, such as therapeutic ultrasound, high power ultrasonic wirebonding, high temperature non-destructive testing, and downhole energy harvesting. This paper will present recent developments of piezoelectric composite technology for high temperature and high power applications. The concerns and limitations of using piezoelectric composites will also be discussed, and the expected future research directions will be outlined. PMID:25111242

Wettability and surface free energy of polarised ceramic biomaterials

International Nuclear Information System (INIS)

Nakamura, Miho; Hori, Naoko; Namba, Saki; Yamashita, Kimihiro; Toyama, Takeshi; Nishimiya, Nobuyuki

2015-01-01

The surface modification of ceramic biomaterials used for medical devices is expected to improve osteoconductivity through control of the interfaces between the materials and living tissues. Polarisation treatment induced surface charges on hydroxyapatite, β-tricalcium phosphate, carbonate-substituted hydroxyapatite and yttria-stabilized zirconia regardless of the differences in the carrier ions participating in the polarisation. Characterization of the surfaces revealed that the wettability of the polarised ceramic biomaterials was improved through the increase in the surface free energies compared with conventional ceramic surfaces. (note)

Effects of Bi(Zn2/3Nb1/3)O3 Modification on the Relaxor Behavior and Piezoelectricity of Pb(Mg1/3Nb2/3)O3-PbTiO3 Ceramics.

Science.gov (United States)

Liu, Zenghui; Wu, Hua; Paterson, Alisa; Ren, Wei; Ye, Zuo-Guang

2017-10-01

Relaxor lead magnesium niobate (PMN)-based materials exhibit complex structures and unusual properties that have been puzzling researchers for decades. In this paper, a new ternary solid solution of Pb(Mg 1/3 Nb 2/3 )O 3 -PbTiO 3 -Bi(Zn 2/3 Nb 1/3 )O 3 (PMN-PT-BZN) is prepared in the form of ceramics, and the effects of the incorporation of BZN into the PMN-PT binary system are investigated. The crystal structure favors a pseudocubic symmetry and the relaxor properties are enhanced as the concentration of BZN increases. The relaxor behavior and the related phase transformations are studied by dielectric spectroscopy. A phase diagram mapping out the characteristic temperatures and various states is established. Interestingly, the piezoelectricity of the PMN-PT ceramics is significantly enhanced by the BZN substitution, with an optimal value of d 33 reaching 826 pC/N for 0.96[0.7Pb(Mg 1/3 Nb 2/3 )O 3 -0.3PbTiO 3 ]-0.04Bi(Zn 2/3 Nb 1/3 )O 3 . This paper provides a better understanding of the relaxor ferroelectric behavior, and unveils a new relaxor-based ternary system as piezoelectric materials potentially useful for electromechanical transducer applications.

Bulletin of Materials Science | Indian Academy of Sciences

Indian Academy of Sciences (India)

Abstract. NaSr2Nb5O15 lead-free piezoelectric ceramics were prepared by the sol–gel method; they were sintered at different temperatures with or without protective atmosphere. The influences of sintering temperature and protective atmosphere on the characterization and properties of the ceramics were investigated.

Structure and electrical properties of new Aurivillius oxides (K0.16Na0.84)0.5Bi4.5Ti4O15 with manganese modification

International Nuclear Information System (INIS)

Fang, Pinyang; Liu, Peng; Xi, Zengzhe; Long, Wei; Li, Xiaojuan

2014-01-01

Highlights: • Manganese modified KNBT ceramics were synthesized using the solid state process. • d 33 and T c of KNBT ceramics were improved by manganese modification. • d 33 and T c of KNBT-Mn50 ceramic were 28 pC/N and 657 °C, respectively. - Abstract: Aurivillius oxides, (K 0.16 Na 0.84 ) 0.5 Bi 4.5 Ti 4 O 15 (KNBT) with manganese doping, were synthesized by using the conventional solid state reaction method. Influence of manganese doping on structure and electric properties of the KNBT ceramics was investigated. Phase analysis was performed by X-ray diffraction analyses (XRD) and Raman spectroscopy. Microstructural morphology was assessed by the scanning electron microscopy (SEM). Piezoelectric performances of manganese modified KNBT ceramics were improved significantly compared with that of the KNBT ceramic. The maximum of piezoelectric coefficient (d 33 ) was found to be 28 pC/N for the KNBT-Mn50 ceramic, together with high Curie temperature (T c ∼ 657 °C) and high resistivity (higher than 10 6 Ω cm). In addition, excellent temperature stability of piezoelectric performances was exhibited for manganese modified KNBT lead-free piezoelectric ceramics

Effect of Polymer Matrix on the Structure and Electric Properties of Piezoelectric Lead Zirconatetitanate/Polymer Composites

Directory of Open Access Journals (Sweden)

Rui Li

2017-08-01

Full Text Available Piezoelectric lead zirconatetitanate (PZT/polymer composites were prepared by two typical polymer matrixes using the hot-press method. The micromorphology, microstructure, dielectric properties, and piezoelectric properties of the PZT/polymer composites were characterized and investigated. The results showed that when the condition of frequency is 103 Hz, the dielectric and piezoelectric properties of PZT/poly(vinylidene fluoride were both better than that of PZT/polyvinyl chloride (PVC. When the volume fraction of PZT was 50%, PZT/PVDF prepared by the hot-press method had better comprehensive electric property.

Converse Piezoelectric Effect Induced Transverse Deflection of a Free-Standing ZnO Microbelt

KAUST Repository

Hu, Youfan; Gao, Yifan; Singamaneni, Srikanth; Tsukruk, Vladimir V.; Wang, Zhong Lin

2009-01-01

We demonstrate the first electric field induced transverse deflection of a single-crystal, free-standing ZnO microbelt as a result of converse piezoelectric effect. For a microbelt growing along the c-axis, a shear stress in the a-c plane can

Giant piezoelectric voltage coefficient in grain-oriented modified PbTiO3 material.

Science.gov (United States)

Yan, Yongke; Zhou, Jie E; Maurya, Deepam; Wang, Yu U; Priya, Shashank

2016-10-11

A rapid surge in the research on piezoelectric sensors is occurring with the arrival of the Internet of Things. Single-phase oxide piezoelectric materials with giant piezoelectric voltage coefficient (g, induced voltage under applied stress) and high Curie temperature (T c ) are crucial towards providing desired performance for sensing, especially under harsh environmental conditions. Here, we report a grain-oriented (with 95% texture) modified PbTiO 3 ceramic that has a high T c (364 °C) and an extremely large g 33 (115 × 10 -3  Vm N -1 ) in comparison with other known single-phase oxide materials. Our results reveal that self-polarization due to grain orientation along the spontaneous polarization direction plays an important role in achieving large piezoelectric response in a domain motion-confined material. The phase field simulations confirm that the large piezoelectric voltage coefficient g 33 originates from maximized piezoelectric strain coefficient d 33 and minimized dielectric permittivity ɛ 33 in [001]-textured PbTiO 3 ceramics where domain wall motions are absent.

Determination of the reduced matrix of the piezoelectric, dielectric, and elastic material constants for a piezoelectric material with C∞ symmetry.

Science.gov (United States)

Sherrit, Stewart; Masys, Tony J; Wiederick, Harvey D; Mukherjee, Binu K

2011-09-01

We present a procedure for determining the reduced piezoelectric, dielectric, and elastic coefficients for a C(∞) material, including losses, from a single disk sample. Measurements have been made on a Navy III lead zirconate titanate (PZT) ceramic sample and the reduced matrix of coefficients for this material is presented. In addition, we present the transform equations, in reduced matrix form, to other consistent material constant sets. We discuss the propagation of errors in going from one material data set to another and look at the limitations inherent in direct calculations of other useful coefficients from the data.

Structural Evolution of the R-T Phase Boundary in KNN-Based Ceramics

KAUST Repository

Lv, Xiang

2017-10-04

Although a rhombohedral-tetragonal (R-T) phase boundary is known to substantially enhance the piezoelectric properties of potassium-sodium niobate ceramics, the structural evolution of the R-T phase boundary itself is still unclear. In this work, the structural evolution of R-T phase boundary from -150 °C to 200 °C is investigated in (0.99-x)K0.5Na0.5Nb1-ySbyO3-0.01CaSnO3-xBi0.5K0.5HfO3 (where x=0~0.05 with y=0.035, and y=0~0.07 with x=0.03) ceramics. Through temperature-dependent powder X-ray diffraction (XRD) patterns and Raman spectra, the structural evolution was determined to be Rhombohedral (R, <-125 °C) → Rhombohedral+Orthorhombic (R+O, -125 °C to 0 °C) → Rhombohedral+Tetragonal (R+T, 0 °C to 150 °C) → dominating Tetragonal (T, 200 °C to Curie temperature (TC)) → Cubic (C, >TC). In addition, the enhanced electrical properties (e.g., a direct piezoelectric coefficient (d33) of ~450±5 pC/N, a conversion piezoelectric coefficient (d33*) of ~580±5 pm/V, an electromechanical coupling factor (kp) of ~0.50±0.02, and TC~250 °C), fatigue-free behavior, and good thermal stability were exhibited by the ceramics possessing the R-T phase boundary. This work improves understanding of the physical mechanism behind the R-T phase boundary in KNN-based ceramics and is an important step towards their adoption in practical applications. This article is protected by copyright. All rights reserved.

In-situ poling and structurization of piezoelectric particulate composites.

Science.gov (United States)

Khanbareh, H; van der Zwaag, S; Groen, W A

2017-11-01

Composites of lead zirconate titanate particles in an epoxy matrix are prepared in the form of 0-3 and quasi 1-3 with different ceramic volume contents from 10% to 50%. Two different processing routes are tested. Firstly a conventional dielectrophoretic structuring is used to induce a chain-like particle configuration, followed by curing the matrix and poling at a high temperature and under a high voltage. Secondly a simultaneous combination of dielectrophoresis and poling is applied at room temperature while the polymer is in the liquid state followed by subsequent curing. This new processing route is practiced in an uncured thermoset system while the polymer matrix still possess a relatively high electrical conductivity. Composites with different degrees of alignment are produced by altering the magnitude of the applied electric field. A significant improvement in piezoelectric properties of quasi 1-3 composites can be achieved by a combination of dielectrophoretic alignment of the ceramic particles and poling process. It has been observed that the degree of structuring as well as the functional properties of the in-situ structured and poled composites enhance significantly compared to those of the conventionally manufactured structured composites. Improving the alignment quality enhances the piezoelectric properties of the particulate composites.

Industrial ceramics - Properties, forming and applications

International Nuclear Information System (INIS)

Fantozzi, Gilbert; Niepce, Jean-Claude; Bonnefont, Guillaume; Alary, J.A.; Allard, B.; Ayral, A.; Bassat, J.M.; Elissalde, C.; Maglione, M.; Beauvy, M.; Bertrand, G.; Bignon, A.; Billieres, D.; Blanc, J.J.; Blumenfeld, P.; Bonnet, J.P.; Bougoin, M.; Bourgeon, M.; Boussuge, M.; Thorel, A.; Bruzek, C.E.; Cambier, F.; Carrerot, H.; Casabonne, J.M.; Chaix, J.M.; Chevalier, J.; Chopinet, M.H.; Couque, H.; Courtois, C.; Leriche, A.; Dhaler, D.; Denape, J.; Euzen, P.; Ganne, J.P.; Gauffinet, S.; Girard, A.; Gonon, M.; Guizard, C.; Hampshire, S.; Joulin, J.P.; Julbe, A.; Ferrato, M.; Fontaine, M.L.; Lebourgeois, R.; Lopez, J.; Maquet, M.; Marinel, S.; Marrony, M.; Martin, J.F.; Mougin, J.; Pailler, R.; Pate, M.; Petitpas, E.; Pijolat, C.; Pires-Franco, P.; Poirier, C.; Poirier, J.; Pourcel, F.; Potier, A.; Tulliani, J.M.; Viricelle, J.P.; Beauger, A.

2013-01-01

After a general introduction to ceramics (definition, general properties, elaboration, applications, market data), this book address conventional ceramics (elaboration, material types), thermo-structural ceramics (oxide based ceramics, non-oxide ceramics, fields of application, functional coatings), refractory ceramics, long fibre and ceramic matrix composites, carbonaceous materials, ceramics used for filtration, catalysis and the environment, ceramics for biomedical applications, ceramics for electronics and electrical engineering (for capacitors, magnetic, piezoelectric, dielectric ceramics, ceramics for hyper-frequency resonators), electrochemical ceramics, transparent ceramics (forming and sintering), glasses, mineral binders. The last chapter addresses ceramics used in the nuclear energy sector: in nuclear fuels and fissile material, absorbing ceramics and shields, in the management of nuclear wastes, new ceramics for reactors under construction or for future nuclear energy

Surface energy effect on free vibration of nano-sized piezoelectric double-shell structures

Science.gov (United States)

Fang, Xue-Qian; Zhu, Chang-Song; Liu, Jin-Xi; Liu, Xiang-Lin

2018-01-01

Combining Goldenveizer-Novozhilov shell theory, thin plate theory and electro-elastic surface theory, the size-dependent vibration of nano-sized piezoelectric double-shell structures under simply supported boundary condition is presented, and the surface energy effect on the natural frequencies is discussed. The displacement components of the cylindrical nano-shells and annular nano-plates are expanded as the superposition of standard Fourier series based on Hamilton's principle. The total stresses with consideration of surface energy effect are derived, and the total energy function is obtained by using Rayleigh-Ritz energy method. The free vibration equation is solved, and the natural frequency is analyzed. In numerical examples, it is found that the surface elastic constant, piezoelectric constant and surface residual stress show different effects on the natural frequencies. The effect of surface piezoelectric constant is the maximum. The effect of dimensions of the double-shell under different surface material properties is also examined.

A measurement method for piezoelectric material properties under longitudinal compressive stress–-a compression test method for thin piezoelectric materials

International Nuclear Information System (INIS)

Kang, Lae-Hyong; Lee, Dae-Oen; Han, Jae-Hung

2011-01-01

We introduce a new compression test method for piezoelectric materials to investigate changes in piezoelectric properties under the compressive stress condition. Until now, compression tests of piezoelectric materials have been generally conducted using bulky piezoelectric ceramics and pressure block. The conventional method using the pressure block for thin piezoelectric patches, which are used in unimorph or bimorph actuators, is prone to unwanted bending and buckling. In addition, due to the constrained boundaries at both ends, the observed piezoelectric behavior contains boundary effects. In order to avoid these problems, the proposed method employs two guide plates with initial longitudinal tensile stress. By removing the tensile stress after bonding a piezoelectric material between the guide layers, longitudinal compressive stress is induced in the piezoelectric layer. Using the compression test specimens, two important properties, which govern the actuation performance of the piezoelectric material, the piezoelectric strain coefficients and the elastic modulus, are measured to evaluate the effects of applied electric fields and re-poling. The results show that the piezoelectric strain coefficient d 31 increases and the elastic modulus decreases when high voltage is applied to PZT5A, and the compression in the longitudinal direction decreases the piezoelectric strain coefficient d 31 but does not affect the elastic modulus. We also found that the re-poling of the piezoelectric material increases the elastic modulus, but the piezoelectric strain coefficient d 31 is not changed much (slightly increased) by re-poling

Characterization of advanced piezoelectric materials in the wide temperature range

Energy Technology Data Exchange (ETDEWEB)

Burianova, L.; Kopal, A.; Nosek, J

2003-05-25

We report about methods and results of our measurements of piezoelectric, dielectric and elastic properties of piezoelectric materials like crystals, ceramics, composites, polymers and thin layer composites. Among the methods, used in our laboratories are: the resonance method working in the temperature range 208-358 K, hydrostatic methods, both static and dynamic in the range 273-333 K, laser interferometric methods, using single and double-beam interferometer, working at room temperature, single and double-beam micro-interferometers, working inside of optical cryostat in the range 150-330 K, and pulse echo method for measurements of elastic coefficients, using ultrasonic set, working at room temperature. In our earlier papers we reported about some of our results of piezoelectric measurements of PZT ceramics using resonance method and laser interferometric method. The results of both methods were in good agreement. Now, the measurements are realized on 0-3 ceramic-polymer composites and thin layer composites. It is well known, that both intrinsic (material) and extrinsic (domain structure) contributions to properties of ferroelectric samples have characteristic, sometimes rather strong, temperature dependence. Therefore, any extension of temperature range of the above mentioned methods is welcomed.

Enhanced piezoelectric properties and excellent thermal stabilities of cobalt-modified Aurivillius-type calcium bismuth titanate (CaBi_4Ti_4O_1_5)

International Nuclear Information System (INIS)

Zhao, Tian-Long; Wang, Chun-Ming; Wang, Chun-Lei; Wang, Yi-Ming; Dong, Shuxiang

2015-01-01

Highlights: • Cobalt oxide modified CBT-based ceramics were prepared and investigated in detail. • XRPD analysis revealed Co ions enter into B-site of CBT-based ceramics. • CBT-Co4 ceramics show the enhanced d_3_3 of 14 pC/N and T_c of 782 °C. • CBT-Co4 ceramics present the improved high-temperature resistivity. • Thermal depoling behavior indicates CBT-Co4 ceramics exhibit good thermal stability. - Abstract: Bismuth layer-structured ferroelectric (BLSF) calcium bismuth titanate (CaBi_4Ti_4O_1_5, CBT) piezoelectric ceramics with 0.0–1.0 wt.% cobalt oxide (Co_2O_3) have been prepared via a conventional solid-state reaction method. Microstructural morphology and electrical properties of cobalt oxide-modified CBT ceramics were investigated in detail. X-ray powder diffraction (XRPD) analysis revealed that the cobalt oxide-modified CBT ceramics have a pure four-layer Aurivillius-type structure. The piezoelectric properties of CBT ceramics were significantly enhanced by cobalt oxide modifications. The piezoelectric coefficient d_3_3 and Curie temperature T_c of 0.2 wt.% cobalt oxide-modified CBT ceramics (CBT-Co4) are 14 pC/N and 782 °C, respectively. The DC resistivity and thermal depoling behavior at elevated temperature indicated that the CBT-Co4 ceramics exhibit good thermal stability, demonstrating that the CBT-Co4 ceramics are potential materials for high temperature piezoelectric applications.

High-Throughput Investigation of a Lead-Free AlN-Based Piezoelectric Material, (Mg,Hf)xAl1-xN.

Science.gov (United States)

Nguyen, Hung H; Oguchi, Hiroyuki; Van Minh, Le; Kuwano, Hiroki

2017-06-12

We conducted a high-throughput investigation of the fundamental properties of (Mg,Hf) x Al 1-x N thin films (0 piezoelectric materials. For the high-throughput investigation, we prepared composition-gradient (Mg,Hf) x Al 1-x N films grown on a Si(100) substrate at 600 °C by cosputtering AlN and MgHf targets. To measure the properties of the various compositions at different positions within a single sample, we used characterization techniques with spatial resolution. X-ray diffraction (XRD) with a beam spot diameter of 1.0 mm verified that Mg and Hf had substituted into the Al sites and caused an elongation of the c-axis of AlN from 5.00 Å for x = 0 to 5.11 Å for x = 0.24. In addition, the uniaxial crystal orientation and high crystallinity required for piezoelectric materials to be used as application devices were confirmed. The piezoelectric response microscope indicated that this c-axis elongation increased the piezoelectric coefficient almost linearly from 1.48 pm/V for x = 0 to 5.19 pm/V for x = 0.24. The dielectric constants of (Mg,Hf) x Al 1-x N were investigated using parallel plate capacitor structures with ∼0.07 mm 2 electrodes and showed a slight increase by substitution. These results verified that (Mg,Hf) x Al 1-x N is a promising material for piezoelectric-based application devices, especially for vibrational energy harvesters.

Revisiting the Characterization of the Losses in Piezoelectric Materials from Impedance Spectroscopy at Resonance

Directory of Open Access Journals (Sweden)

Amador M. González

2016-01-01

Full Text Available Electronic devices using the piezoelectric effect contain piezoelectric materials: often crystals, but in many cases poled ferroelectric ceramics (piezoceramics, polymers or composites. On the one hand, these materials exhibit non-negligible losses, not only dielectric, but also mechanical and piezoelectric. In this work, we made simulations of the effect of the three types of losses in piezoelectric materials on the impedance spectrum at the resonance. We analyze independently each type of loss and show the differences among them. On the other hand, electrical and electronic engineers include piezoelectric sensors in electrical circuits to build devices and need electrical models of the sensor element. Frequently, material scientists and engineers use different languages, and the characteristic material coefficients do not have a straightforward translation to those specific electrical circuit components. To connect both fields of study, we propose the use of accurate methods of characterization from impedance measurements at electromechanical resonance that lead to determination of all types of losses, as an alternative to current standards. We introduce a simplified equivalent circuit model with electrical parameters that account for piezoceramic losses needed for the modeling and design of industrial applications.

Revisiting the Characterization of the Losses in Piezoelectric Materials from Impedance Spectroscopy at Resonance.

Science.gov (United States)

González, Amador M; García, Álvaro; Benavente-Peces, César; Pardo, Lorena

2016-01-26

Electronic devices using the piezoelectric effect contain piezoelectric materials: often crystals, but in many cases poled ferroelectric ceramics (piezoceramics), polymers or composites. On the one hand, these materials exhibit non-negligible losses, not only dielectric, but also mechanical and piezoelectric. In this work, we made simulations of the effect of the three types of losses in piezoelectric materials on the impedance spectrum at the resonance. We analyze independently each type of loss and show the differences among them. On the other hand, electrical and electronic engineers include piezoelectric sensors in electrical circuits to build devices and need electrical models of the sensor element. Frequently, material scientists and engineers use different languages, and the characteristic material coefficients do not have a straightforward translation to those specific electrical circuit components. To connect both fields of study, we propose the use of accurate methods of characterization from impedance measurements at electromechanical resonance that lead to determination of all types of losses, as an alternative to current standards. We introduce a simplified equivalent circuit model with electrical parameters that account for piezoceramic losses needed for the modeling and design of industrial applications.

Lead poisoning from drinking Kombucha tea brewed in a ceramic pot.

Science.gov (United States)

Phan, T G; Estell, J; Duggin, G; Beer, I; Smith, D; Ferson, M J

Kombucha tea is an alternative therapy that is gaining popularity as a remedy for a diverse range of ailments. We report two cases of symptomatic lead poisoning requiring chelation therapy in a married couple who had been drinking Kombucha tea for six months, brewing the tea in a ceramic pot. We postulate that acids in the tea eluted lead from the glaze pigment used in the ceramic pot, in a manner analogous to elution of lead from crystal decanters by wine and spirits.

Synthesis and piezoelectric properties of (1 - x)Bi0.5(Na0.8K0.2)0.5TiO3-xSr2ZrTiO6 ceramics

Science.gov (United States)

Onishi, Ryo; Ogawa, Hirotaka; Iida, Daiki; Kan, Akinori

2017-10-01

The effects of Sr2ZrTiO6 (SZT) addition on the piezoelectric properties of (1 - x)Bi0.5(Na0.8K0.2)0.5TiO3 (BNKT)-xSZT ceramics were characterized in this study. The X-ray powder diffraction (XRPD) profiles and Raman spectra of the ceramics in the composition range of 0-0.02 implies the presence of morphotropic phase boundary (MPB) which consists of the rhombohedral and tetragonal phases. Moreover, the temperature dependence of dielectric loss indicated a presence of the ferroelectric-relaxor transition temperature (T F-R) of around 75 °C for x = 0.005 and the temperature dependence shifted to a lower temperature at x = 0.01. The temperature dependence of the P-E hysteresis loop of the ceramics at the compositions of x = 0.005-0.02 showed pinched hysteresis loops above T F-R. Regarding the piezoelectric constant (d 33), it was increased by SZT addition in the MPB region (x = 0-0.01) and the highest d 33 of 202 pC/N was obtained at the composition of x = 0.0025. The S-E unipolar loop was also evaluated, the strain of the ceramic increased up to x = 0.02; and the highest d33* = 436 pm/V was obtained at the composition of x = 0.02.

Photothermoacoustic effect in solids with piezoelectric detection

International Nuclear Information System (INIS)

Kozachenko, V. V.; Kucherov, I.Ya.

2004-01-01

Full text: In the last few years, a growing interest has been expressed in studies of substances in different aggregate states which were performed with the help of the photothermoacoustic PTA effect. Main in this method is use of thermal waves as the carrier of the information about properties of explored substance. The excitation of thermal waves is carried out, as a rule, by modulated light flux. A specific feature of the PTA effect is the dependence of the information obtained from it on the method used for detecting thermal waves. One of the most sensitive methods for detecting a PTA signal is the piezoelectric method. For studies of solids, the PTA effect in plates offers considerable promise. In this work, PTA effect in a solid-piezoelectric layered structure is studied theoretically and experimentally. The layered plate consisting of an isotropic solid and piezoelectric crystal of a class 6 mm (or piezoelectric ceramics) is considered. The surface of a solid body is uniformly irradiated with a modulated light flux. The sample is heated and the thermal waves are generated. In the sample, the temperature field of thermal waves generates, due to the thermoelastic effect, acoustic vibration and waves that are registered by a piezoelectric. Expressions for the potential difference U across an arbitrary layer of piezoelectric transducer are derived. The solid bodies with various optical and thermal properties for cases of one-layer and two-layer piezoelectric transducer are analyzed. In particular, is shown, that for the case two-layer piezoelectric transducer, in the high-frequency region, the amplitude ratio U 1 / U 2 the tangent of the phase difference tg(Δφ) of signals taken from individual layers of the transducer depend almost linearly on the inverse square root of the frequency f -1/2 . With use of these features, the new method of definition of some elastic and thermal parameters of solid bodies offered. An experiment is performed with samples Cu, Fe

Microscopic origins of the large piezoelectricity of leadfree (Ba,Ca)(Zr,Ti)O3.

Science.gov (United States)

Nahas, Yousra; Akbarzadeh, Alireza; Prokhorenko, Sergei; Prosandeev, Sergey; Walter, Raymond; Kornev, Igor; Íñiguez, Jorge; Bellaiche, L

2017-06-20

In light of directives around the world to eliminate toxic materials in various technologies, finding lead-free materials with high piezoelectric responses constitutes an important current scientific goal. As such, the recent discovery of a large electromechanical conversion near room temperature in (1-x)Ba(Zr 0.2 Ti 0.8 )O 3 -x(Ba 0.7 Ca 0.3 )TiO 3 compounds has directed attention to understanding its origin. Here, we report the development of a large-scale atomistic scheme providing a microscopic insight into this technologically promising material. We find that its high piezoelectricity originates from the existence of large fluctuations of polarization in the orthorhombic state arising from the combination of a flat free-energy landscape, a fragmented local structure, and the narrow temperature window around room temperature at which this orthorhombic phase is the equilibrium state. In addition to deepening the current knowledge on piezoelectricity, these findings have the potential to guide the design of other lead-free materials with large electromechanical responses.

Temperature stability and electrical properties in La-doped KNN-based ceramics

KAUST Repository

Lv, Xiang; Wu, Jiagang; Zhu, Jianguo; Xiao, Dingquan; Zhang, Xixiang

2018-01-01

To improve the temperature stability and electrical properties of KNN‐based ceramics, we simultaneously consider the phase boundary and the addition of rare earth element (La), 0.96K0.5Na0.5Nb0.96Sb0.04O3‐0.04(Bi1‐xLax)0.5Na0.5ZrO3 (0 ≤ x ≤ 1.0) ceramics. More specifically, we investigate how the phase boundary and the addition of La3+ affect the phase structure, electrical properties, and temperature stability of the ceramic. We show that increasing the La3+ content leads to a change in phase structure, from a rhombohedral‐tetragonal (R‐T) phase coexistence to a cubic phase. More importantly, we show that the appropriate addition of La3+ (x = 0.2) can simultaneously improve the unipolar strain (from 0.127% to 0.147%) and the temperature stability (i.e., the unipolar strain of 0.147% remains unchanged when T is increased from 25 to 80°C). In addition, we find that the ceramics with x = 0.2 exhibit a large piezoelectric constant (d33) of ~430 pC/N, a high Curie temperature (TC) of ~240°C and a fatigue‐free behavior (after 106 electric cycles). The enhanced electrical properties mostly originate from the easy domain switching, whereas the improved temperature stability can be attributed to the R‐T phase boundary and the appropriate addition of La3+.

Temperature stability and electrical properties in La-doped KNN-based ceramics

KAUST Repository

Lv, Xiang

2018-04-16

To improve the temperature stability and electrical properties of KNN‐based ceramics, we simultaneously consider the phase boundary and the addition of rare earth element (La), 0.96K0.5Na0.5Nb0.96Sb0.04O3‐0.04(Bi1‐xLax)0.5Na0.5ZrO3 (0 ≤ x ≤ 1.0) ceramics. More specifically, we investigate how the phase boundary and the addition of La3+ affect the phase structure, electrical properties, and temperature stability of the ceramic. We show that increasing the La3+ content leads to a change in phase structure, from a rhombohedral‐tetragonal (R‐T) phase coexistence to a cubic phase. More importantly, we show that the appropriate addition of La3+ (x = 0.2) can simultaneously improve the unipolar strain (from 0.127% to 0.147%) and the temperature stability (i.e., the unipolar strain of 0.147% remains unchanged when T is increased from 25 to 80°C). In addition, we find that the ceramics with x = 0.2 exhibit a large piezoelectric constant (d33) of ~430 pC/N, a high Curie temperature (TC) of ~240°C and a fatigue‐free behavior (after 106 electric cycles). The enhanced electrical properties mostly originate from the easy domain switching, whereas the improved temperature stability can be attributed to the R‐T phase boundary and the appropriate addition of La3+.

Shear piezoelectric coefficients of PZT, LiNbO3 and PMN-PT at cryogenic temperatures

International Nuclear Information System (INIS)

Bukhari, Syed; Islam, Md; Haziot, Ariel; Beamish, John

2014-01-01

Piezoelectric transducers are used to detect stress and to generate nanometer scale displacements but their piezoelectric coefficients decrease with temperature, limiting their performance in cryogenic applications. We have developed a capacitive technique and directly measured the temperature dependence of the shear coefficient d 15 for ceramic lead zirconium titanate (PZT), 41° X-cut lithium niobate (LiNbO 3 ) and single crystal lead magnesium niobium-lead titanate (PMN-PT). In PZT, d 15 decreases nearly linearly with temperature, dropping by factor of about 4 by 1.3 K. LiNbO3 has the smallest room temperature d15, but its value decreased by only 6% at the lowest temperatures. PMN-PT had the largest value of d15 at room temperature (2.9 × 10 −9 m/V, about 45 times larger than for LiNbO 3 ) but it decreased rapidly below 75 K; at 1.3 K, d 15 was only about 8% of its room temperature value

Experimental measurements and finite element models of High Displacement Piezoelectric Actuators.

Science.gov (United States)

Camargo, Gilberto; Ashford, Gevale; Naco, Eris; Usher, Tim

2004-03-01

Piezoelectric actuators have many applications including morphable wing technology and piezoelectric transformers. A Piezoelectric ceramic is a material that will move when a voltage is applied and conversely produces a charge when a pressure is applied. In our study, we examine THUNDER (Thin Layer Unimorph Ferroelectric Driver and Sensor) actuators (Thunder TM is a trademark of FACE International Corporation.) Thunder actuators are constructed by bonding thin PZT piezoelectric ceramics to metal sheets. We will present physical measurements of piezoelectric actuators, as well as measurements of the displacements due to applied voltages. In our studies we used a laser micrometer to measure the dimensional characteristics of four sizes of THUNDER actuators including TH-8R, TH-9R, TH-10R, and finally the TH-11R. We also developed computer models using a commercial fine element modeling package (FEM) known as ANSYS6.0®. This software enables us to construct our models controlling such attributes as exact dimensions of the three layers of the piezoelectric actuator, the material properties of each element, the type of load that is to be applied as well as the manner in which the layers are bonded together. The computer model compares favorably with the experimental results. Acknowledgements: NASA Grant No. 0051-0078 Department of Defense (DoD) Control No.ISP02-EUG15

Mechanical and dielectric characterization of lead zirconate titanate(PZT)/polyurethane(PU) thin film composite for energy harvesting

Science.gov (United States)

Aboubakr, S.; Rguiti, M.; Hajjaji, A.; Eddiai, A.; Courtois, C.; d'Astorg, S.

2014-04-01

The Lead Zirconate titanate (PZT) ceramic is known by its piezoelectric feature, but also by its stiffness, the use of a composite based on a polyurethane (PU) matrix charged by a piezoelectric material, enable to generate a large deformation of the material, therefore harvesting more energy. This new material will provide a competitive alternative and low cost manufacturing technology of autonomous systems (smart clothes, car seat, boat sail, flag ...). A thin film of the PZT/PU composite was prepared using up to 80 vol. % of ceramic. Due to the dielectric nature of the PZT, inclusions of this one in a PU matrix raises the permittivity of the composite, on other hand this latter seems to decline at high frequencies.

Enhanced piezoelectricity in A B O3 ferroelectrics via intrinsic stress-driven flattening of the free-energy profile

Science.gov (United States)

Feng, Yu; Li, Wei-Li; Yu, Yang; Jia, He-Nan; Qiao, Yu-Long; Fei, Wei-Dong

2017-11-01

An approach to greatly enhance the piezoelectric properties (˜4 00 pC/N) of the tetragonal BaTi O3 polycrystal using a small number of A -site acceptor-donor substitutions [D. Xu et al., Acta Mater. 79, 84 (2014), 10.1016/j.actamat.2014.07.023] has been proposed. In this study, Pb (ZrTi ) O3 (PZT) based polycrystals with various crystal symmetries (tetragonal, rhombohedral, and so on) were chosen to investigate the piezoelectricity enhancement mechanism. X-ray diffraction results show that doping generates an intrinsic uniaxial compressive stress along the [001] pc direction in the A B O3 lattices. Piezoelectric maps in the parameter space of temperature and Ti concentration in the PZT and doped system show a more significant enhancement effect of L i+-A l3 + codoping in tetragonal PZT than in the rhombohedral phase. Phenomenological thermodynamic analysis indicates that the compressive stress results in more serious flattening of the free-energy profile in tetragonal PZT, compared with that in the rhombohedral phase. The chemical stress obtained by this acceptor-donor codoping can be utilized to optimize the piezoelectric performance on the tetragonal-phase site of the morphotropic phase boundary in the PZT system. The present study provides a promising route to the large piezoelectric effect induced by chemical-stress-driven flattening of the free-energy profile.

A review of the structure-property relationships in lead-free piezoelectric (1−x)Na{sub 0.5}Bi{sub 0.5}TiO{sub 3}–(x)BaTiO{sub 3}

Energy Technology Data Exchange (ETDEWEB)

McQuade, Ryan R.; Dolgos, Michelle R., E-mail: Michelle.Dolgos@oregonstate.edu

2016-10-15

Piezoelectric materials are increasingly being investigated for energy harvesting applications where (1−x)Na{sub 0.5}Bi{sub 0.5}TiO{sub 3}–(x)BaTiO{sub 3} (NBT-BT) is an important lead-free piezoelectric material with potential to be used as an actuator in energy harvesting devices. Much effort has been put into modifying NBT-BT to tune the properties for specific applications, but there is currently no consensus regarding the structure-property relationships in this material, making targeted, rational design a major challenge. In this review, we will summarize the current body of knowledge of NBT-BT and discuss contradicting studies, unresolved problems, and future directions in the field. - Graphical abstract: This review of (1−x)Na{sub 0.5}Bi{sub 0.5}TiO{sub 3}–(x)BaTiO{sub 3} (NBT-BT) summarizes the large body of literature regarding the structure-property relationships of this complex material. We highlight structural studies of the average and local structures of both unpoled and poled samples of NBT-BT at its morphotropic phase boundary and discuss them in context of the observed piezoelectric properties. - Highlights: • Local and average structure of NBT-BT at morphotropic phase boundary is reviewed. • Average structure of poled and unpoled samples of NBT-BT is discussed. • Structure-property relationships in NBT-BT and future directions are summarized.

Towards a digital sound reconstruction MEMS device: Characterization of a single PZT based piezoelectric actuator

KAUST Repository

Carreno, Armando Arpys Arevalo

2015-04-01

In this paper we report the fabrication and characterization of a single piezoelectric actuator for digital sound reconstruction. This work is the first step towards the implementation of a true digital micro-loudspeaker by means of an array of acoustic actuators. These actuators consist of a flexible membrane fabricated using polyimide, which is actuated using a Lead-Zirconate-Titanate (PZT) piezoelectric ceramic layer working in the d31 actuation mode. The dimensions of the membrane are of 1mm diameter and 4μm in thickness, which is capable of being symmetrically actuated in both upward and downward directions, due to the back etch step releasing the membrane. Our electrical characterization shows an improvement in the polarization of the piezoelectric material after its final etch patterning step, and our mechanical characterization shows the natural modes of resonance of the stacked membrane. © 2015 IEEE.

Dual strain mechanisms in a lead-free morphotropic phase boundary ferroelectric

DEFF Research Database (Denmark)

Walker, Julian; Simons, Hugh; Alikin, Denis O

2016-01-01

Electromechanical properties such as d33 and strain are significantly enhanced at morphotropic phase boundaries (MPBs) between two or more different crystal structures. Many actuators, sensors and MEMS devices are therefore systems with MPBs, usually between polar phases in lead (Pb)-based ferroe......Electromechanical properties such as d33 and strain are significantly enhanced at morphotropic phase boundaries (MPBs) between two or more different crystal structures. Many actuators, sensors and MEMS devices are therefore systems with MPBs, usually between polar phases in lead (Pb......)-based ferroelectric ceramics. In the search for Pb-free alternatives, systems with MPBs between polar and non-polar phases have recently been theorized as having great promise. While such an MPB was identified in rare-earth (RE) modified bismuth ferrite (BFO) thin films, synthesis challenges have prevented its...... realization in ceramics. Overcoming these, we demonstrate a comparable electromechanical response to Pb-based materials at the polar-to-non-polar MPB in Sm modified BFO. This arises from 'dual' strain mechanisms: ferroelectric/ferroelastic switching and a previously unreported electric-field induced...

Enhanced piezoelectric properties and excellent thermal stabilities of cobalt-modified Aurivillius-type calcium bismuth titanate (CaBi{sub 4}Ti{sub 4}O{sub 15})

Energy Technology Data Exchange (ETDEWEB)

Zhao, Tian-Long [School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100 (China); Wang, Chun-Ming, E-mail: wangcm@sdu.edu.cn [School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100 (China); Wang, Chun-Lei; Wang, Yi-Ming [School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100 (China); Dong, Shuxiang [Department of Materials Science and Engineering, College of Engineering, Peking University, Beijing 100871 (China)

2015-11-15

Highlights: • Cobalt oxide modified CBT-based ceramics were prepared and investigated in detail. • XRPD analysis revealed Co ions enter into B-site of CBT-based ceramics. • CBT-Co4 ceramics show the enhanced d{sub 33} of 14 pC/N and T{sub c} of 782 °C. • CBT-Co4 ceramics present the improved high-temperature resistivity. • Thermal depoling behavior indicates CBT-Co4 ceramics exhibit good thermal stability. - Abstract: Bismuth layer-structured ferroelectric (BLSF) calcium bismuth titanate (CaBi{sub 4}Ti{sub 4}O{sub 15}, CBT) piezoelectric ceramics with 0.0–1.0 wt.% cobalt oxide (Co{sub 2}O{sub 3}) have been prepared via a conventional solid-state reaction method. Microstructural morphology and electrical properties of cobalt oxide-modified CBT ceramics were investigated in detail. X-ray powder diffraction (XRPD) analysis revealed that the cobalt oxide-modified CBT ceramics have a pure four-layer Aurivillius-type structure. The piezoelectric properties of CBT ceramics were significantly enhanced by cobalt oxide modifications. The piezoelectric coefficient d{sub 33} and Curie temperature T{sub c} of 0.2 wt.% cobalt oxide-modified CBT ceramics (CBT-Co4) are 14 pC/N and 782 °C, respectively. The DC resistivity and thermal depoling behavior at elevated temperature indicated that the CBT-Co4 ceramics exhibit good thermal stability, demonstrating that the CBT-Co4 ceramics are potential materials for high temperature piezoelectric applications.

Design and Research of Piezoelectric Ceramics Drive Power

Directory of Open Access Journals (Sweden)

Guang Ya LIU

2014-01-01

Full Text Available Piezoelectric amplifier is a very important part of the piezoelectric actuator. It does not only require high positioning accuracy, but also high frequency response. This paper designs the error amplifier drive power consisting of high-voltage op amp and discrete components, consisting of an error-amplified circuit, a power amplifier circuit, a feedback network and a discharge circuit. A compensation technique based on feedback zero compensation is proposed and it increases the frequency bandwidth and dynamic characteristics of the PZT power effectively. Through the power of the theoretical analysis and Multisim software simulation, the power supply has a good drive capability.

Bone-Inspired Spatially Specific Piezoelectricity Induces Bone Regeneration.

Science.gov (United States)

Yu, Peng; Ning, Chengyun; Zhang, Yu; Tan, Guoxin; Lin, Zefeng; Liu, Shaoxiang; Wang, Xiaolan; Yang, Haoqi; Li, Kang; Yi, Xin; Zhu, Ye; Mao, Chuanbin

2017-01-01

The extracellular matrix of bone can be pictured as a material made of parallel interspersed domains of fibrous piezoelectric collagenous materials and non-piezoelectric non-collagenous materials. To mimic this feature for enhanced bone regeneration, a material made of two parallel interspersed domains, with higher and lower piezoelectricity, respectively, is constructed to form microscale piezoelectric zones (MPZs). The MPZs are produced using a versatile and effective laser-irradiation technique in which K 0.5 Na 0.5 NbO 3 (KNN) ceramics are selectively irradiated to achieve microzone phase transitions. The phase structure of the laser-irradiated microzones is changed from a mixture of orthorhombic and tetragonal phases (with higher piezoelectricity) to a tetragonal dominant phase (with lower piezoelectricity). The microzoned piezoelectricity distribution results in spatially specific surface charge distribution, enabling the MPZs to bear bone-like microscale electric cues. Hence, the MPZs induce osteogenic differentiation of stem cells in vitro and bone regeneration in vivo even without being seeded with stem cells. The concept of mimicking the spatially specific piezoelectricity in bone will facilitate future research on the rational design of tissue regenerative materials.

Impedance-based structural health monitoring of additive manufactured structures with embedded piezoelectric wafers

Science.gov (United States)

Scheyer, Austin G.; Anton, Steven R.

2017-04-01

Embedding sensors within additive manufactured (AM) structures gives the ability to develop smart structures that are capable of monitoring the mechanical health of a system. AM provides an opportunity to embed sensors within a structure during the manufacturing process. One major limitation of AM technology is the ability to verify the geometric and material properties of fabricated structures. Over the past several years, the electromechanical impedance (EMI) method for structural health monitoring (SHM) has been proven to be an effective method for sensing damage in structurers. The EMI method utilizes the coupling between the electrical and mechanical properties of a piezoelectric transducer to detect a change in the dynamic response of a structure. A piezoelectric device, usually a lead zirconate titanate (PZT) ceramic wafer, is bonded to a structure and the electrical impedance is measured across as range of frequencies. A change in the electrical impedance is directly correlated to changes made to the mechanical condition of the structure. In this work, the EMI method is employed on piezoelectric transducers embedded inside AM parts to evaluate the feasibility of performing SHM on parts fabricated using additive manufacturing. The fused deposition modeling (FDM) method is used to print specimens for this feasibility study. The specimens are printed from polylactic acid (PLA) in the shape of a beam with an embedded monolithic piezoelectric ceramic disc. The specimen is mounted as a cantilever while impedance measurements are taken using an HP 4194A impedance analyzer. Both destructive and nondestructive damage is simulated in the specimens by adding an end mass and drilling a hole near the free end of the cantilever, respectively. The Root Mean Square Deviation (RMSD) method is utilized as a metric for quantifying damage to the system. In an effort to determine a threshold for RMSD, the values are calculated for the variation associated with taking multiple

Bipolar ferroelectric fatigue in (K0.5Na0.5)(Nb0.7Ta0.3)O3 ceramics and improved fatigue endurance on addition of ZnO

Science.gov (United States)

Vineetha, P.; Shanmuga Priya, B.; Venkata Saravanan, K.

2018-04-01

Ferroelectric ceramics are the key components in piezoelectric devices used today, thus long term reliability is a major industrial concern. The two important things that have to be considered in the ferroelectric material based device are aging and fatigue. The first one describes degradation with time whereas the later one is characterized by the change of material property during electrical loading. In the present work ferroelectric polarization and bipolar fatigue properties of undoped and ZnO doped lead free (K0.5Na0.5)(Nb0.7Ta0.3)O3 (KNNT) ceramics prepared by solid state reaction method were investigated. X-ray diffraction analysis of the samples reveal perovskite monoclinic phase along with the secondary phase of K2Nb4O11. The ferroelectric studies indicate that ZnO addition reduce fatigue as well as a well saturated hysteresis loop is obtained. The results reveal that addition of ZnO enhances the ferroelectric properties of KNNT ceramics.

Electroactive properties of flexible piezoelectric composites

Directory of Open Access Journals (Sweden)

Sakamoto Walter Katsumi

2001-01-01

Full Text Available A flexible piezoelectric composite with 0-3 connectivity, made from Lead Zirconate Titanate (PZT powder and vegetable-based polyurethane (PU, was doped with small amount of semiconductor powder. As a result a composite with 0-0-3 connectivity was obtained. The nature of absorption and steady state electrical conduction and the dielectric behaviour have been studied for this ceramic/polymer composite. The dielectric loss processes of the composite were observed to be dominated by those the polymer. Adding a semiconductor phase in the composite the electrical conductivity can be controlled and a continuous electric flux path could be created between the PZT grains. This composite may be poled at low voltage and in shorter time compared with composites without a conductive phase.

Pyroelectric and dielectric properties of lead-free ferroelectric Ba3Nb2O8 ceramic

International Nuclear Information System (INIS)

Pati, Biswajit; Choudhary, R.N.P.; Das, Piyush R.; Parida, B.N.; Padhee, R.

2014-01-01

Graphical abstract: - Highlights: • Barium orthoniobate (lead-free perovskite) crystallizes as palmierite with structural stability. • The material exhibits ferroelectric phase transition of diffuse-type suitable for devices. • The low values of ε r and tan δ at high frequencies makes it a potential candidate for microwave applications. • The material has very good pyroelectric properties for detector application. • The material exhibits smaller value of dc activation energy. - Abstract: The present study highlights ferroelectric phase transition, dielectric, pyroelectric properties and conduction mechanism of highly crystallized barium orthoniobate (Ba 3 Nb 2 O 8 ) ceramic, prepared by a solid-state reaction technique. X-ray diffraction studies show the formation of a single-phase compound in hexagonal crystal system. Detailed studies of dielectric parameters (ε r and tan δ) of the compound as a function of temperature and frequency reveal their independence over a wide range of temperature and frequency. An anomaly in ε r suggests the possible existence of a ferroelectric–paraelectric phase transition of diffuse-type in the material. The low dielectric loss and moderate relative permittivity make this material (with certain modification) a potential candidate for microwave applications. Studies of pyroelectric properties reveal that the materials have reasonably high figure of merit useful for fabrication of pyroelectric detectors. The low-leakage current and negative temperature coefficient of resistance (NTCR) behavior of the sample have been verified from J–E plots. The nature of variation of dc conductivity with temperature confirms the Arrhenius and NTCR behavior of the material

Giant energy density in [001]-textured Pb(Mg1/3Nb2/3)O3-PbZrO3-PbTiO3 piezoelectric ceramics

Science.gov (United States)

Yan, Yongke; Cho, Kyung-Hoon; Maurya, Deepam; Kumar, Amit; Kalinin, Sergei; Khachaturyan, Armen; Priya, Shashank

2013-01-01

Pb(Zr,Ti)O3 (PZT) based compositions have been challenging to texture or grow in a single crystal form due to the incongruent melting point of ZrO2. Here we demonstrate the method for achieving 90% textured PZT-based ceramics and further show that it can provide highest known energy density in piezoelectric materials through enhancement of piezoelectric charge and voltage coefficients (d and g). Our method provides more than ˜5× increase in the ratio d(textured)/d(random). A giant magnitude of d.g coefficient with value of 59 000 × 10-15 m2 N-1 (comparable to that of the single crystal counterpart and 359% higher than that of the best commercial compositions) was obtained.

Ferroelectric and Piezoelectric properties of (111) oriented lanthanum modified lead zirconate titanate film

International Nuclear Information System (INIS)

Dutta, Soma; Antony Jeyaseelan, A.; Sruthi, S.

2014-01-01

Lanthanum modified lead zirconate titanate (PLZT) thick film with molecular formula of Pb 0.92 La 0.08 (Zr 0.52 Ti 0.48 ) 0.98 O 3 was grown preferentially along (111) direction on Pt/SiO 2 /Si (platinum/silicon oxide/silicon) substrate by spin coating of chemical solution. The directional growth of the film was facilitated by platinum (Pt) (111) template and rapid thermal annealing. X-ray diffraction pattern and atomic force microscopy revealed the preferential growth of the PLZT film. The film was characterized for ferroelectric and detailed piezoelectric properties in a parallel plate capacitor (metal–PLZT–metal) configuration. Ferroelectric characterization of the film showed saturated hysteresis loop with remanent polarization and coercive electric field values of 10.14 μC/cm 2 and 42 kV/cm, respectively, at an applied field of 300 kV/cm. Longitudinal piezoelectric coefficient (d 33,f ) was measured by employing converse piezoelectric effect where electrical charge response and displacement were measured with electrical voltage excitation on the sample electrodes. The effective transverse piezoelectric coefficient (e 31,f ) was derived from charge measurement with an applied mechanical excitation strain by using the four point bending method. d 33,f and e 31,f coefficients of PLZT films were found to be 380 pm/V and − 0.831 C/m 2 respectively. - Highlights: • PLZT (111) film is prepared by spin coating of chemical sol on Pt (111) template. • Piezoelectric d 33 value (380 pm/V) of PLZT film is found 20% higher than PZT. • Transverse piezocoefficient e 31,f of PLZT film is reported for the first time

Enhanced pyroelectric and piezoelectric properties of PZT with aligned porosity for energy harvesting applications† †Electronic supplementary information (ESI) available. See DOI: 10.1039/c7ta00967d Click here for additional data file.

Science.gov (United States)

Zhang, Yan; Xie, Mengying; Roscow, James; Bao, Yinxiang; Zhou, Kechao

2017-01-01

This paper demonstrates the significant benefits of exploiting highly aligned porosity in piezoelectric and pyroelectric materials for improved energy harvesting performance. Porous lead zirconate (PZT) ceramics with aligned pore channels and varying fractions of porosity were manufactured in a water-based suspension using freeze-casting. The aligned porous PZT ceramics were characterized in detail for both piezoelectric and pyroelectric properties and their energy harvesting performance figures of merit were assessed parallel and perpendicular to the freezing direction. As a result of the introduction of porosity into the ceramic microstructure, high piezoelectric and pyroelectric harvesting figures of merits were achieved for porous freeze-cast PZT compared to dense PZT due to the reduced permittivity and volume specific heat capacity. Experimental results were compared to parallel and series analytical models with good agreement and the PZT with porosity aligned parallel to the freezing direction exhibited the highest piezoelectric and pyroelectric harvesting response; this was a result of the enhanced interconnectivity of the ferroelectric material along the poling direction and reduced fraction of unpoled material that leads to a higher polarization. A complete thermal energy harvesting system, composed of a parallel-aligned PZT harvester element and an AC/DC converter, was successfully demonstrated by charging a storage capacitor. The maximum energy density generated by the 60 vol% porous parallel-connected PZT when subjected to thermal oscillations was 1653 μJ cm–3, which was 374% higher than that of the dense PZT with an energy density of 446 μJ cm–3. The results are beneficial for the design and manufacture of high performance porous pyroelectric and piezoelectric materials in devices for energy harvesting and sensor applications. PMID:28580142

Effects of Ca-dopant on the pyroelectric, piezoelectric and dielectric properties of (Sr 0.6Ba 0.4) 4Na 2Nb 10O 30 ceramics

KAUST Repository

Yao, Yingbang

2012-12-01

Calcium-doped sodium strontium barium niobate (SBNN, (Sr 0.6Ba 0.4) 4-xCa xNa 2Nb 10O 30, 0 ≤ x ≤ 0.5) ceramics were prepared by a conventional solid-state reaction method. SBNN showed \\'filled\\' tetragonal tungsten-bronze structure with fully occupied A-sites. The tetragonal structure, as revealed by X-ray diffraction (XRD) and Raman spectroscopy, was not affected by the Ca-dopant. Effects of Ca-doping concentration on the phase transitions as well as ferroelectric, piezoelectric and pyroelectric properties of the SBNN ceramics were investigated. From the dielectric studies, two anomalies were observed, namely, a sharp normal ferroelectric transition at 260 °C and a broad maximum at round -110 °C. The later was affected by the Ca-doping concentration and its origin was discussed. At x = 0.3, the sample exhibited the highest pyroelectric coefficient of 168 μC/m 2 K and the largest piezoelectric coefficient (d 33) of 63 pC/N at room temperature. On the basis of our results, the pyroelectric properties of the SBNN were improved by Ca-doping. © 2012 Elsevier B.V. All rights reserved.

Effects of Ca-dopant on the pyroelectric, piezoelectric and dielectric properties of (Sr 0.6Ba 0.4) 4Na 2Nb 10O 30 ceramics

KAUST Repository

Yao, Yingbang; Mak, C. L.

2012-01-01

Calcium-doped sodium strontium barium niobate (SBNN, (Sr 0.6Ba 0.4) 4-xCa xNa 2Nb 10O 30, 0 ≤ x ≤ 0.5) ceramics were prepared by a conventional solid-state reaction method. SBNN showed 'filled' tetragonal tungsten-bronze structure with fully occupied A-sites. The tetragonal structure, as revealed by X-ray diffraction (XRD) and Raman spectroscopy, was not affected by the Ca-dopant. Effects of Ca-doping concentration on the phase transitions as well as ferroelectric, piezoelectric and pyroelectric properties of the SBNN ceramics were investigated. From the dielectric studies, two anomalies were observed, namely, a sharp normal ferroelectric transition at 260 °C and a broad maximum at round -110 °C. The later was affected by the Ca-doping concentration and its origin was discussed. At x = 0.3, the sample exhibited the highest pyroelectric coefficient of 168 μC/m 2 K and the largest piezoelectric coefficient (d 33) of 63 pC/N at room temperature. On the basis of our results, the pyroelectric properties of the SBNN were improved by Ca-doping. © 2012 Elsevier B.V. All rights reserved.

Superior piezoelectric composite films: taking advantage of carbon nanomaterials.

Science.gov (United States)

Saber, Nasser; Araby, Sherif; Meng, Qingshi; Hsu, Hung-Yao; Yan, Cheng; Azari, Sara; Lee, Sang-Heon; Xu, Yanan; Ma, Jun; Yu, Sirong

2014-01-31

Piezoelectric composites comprising an active phase of ferroelectric ceramic and a polymer matrix have recently found numerous sensory applications. However, it remains a major challenge to further improve their electromechanical response for advanced applications such as precision control and monitoring systems. We here investigated the incorporation of graphene platelets (GnPs) and multi-walled carbon nanotubes (MWNTs), each with various weight fractions, into PZT (lead zirconate titanate)/epoxy composites to produce three-phase nanocomposites. The nanocomposite films show markedly improved piezoelectric coefficients and electromechanical responses (50%) besides an enhancement of ~200% in stiffness. The carbon nanomaterials strengthened the impact of electric field on the PZT particles by appropriately raising the electrical conductivity of the epoxy. GnPs have been proved to be far more promising in improving the poling behavior and dynamic response than MWNTs. The superior dynamic sensitivity of GnP-reinforced composite may be caused by the GnPs' high load transfer efficiency arising from their two-dimensional geometry and good compatibility with the matrix. The reduced acoustic impedance mismatch resulting from the improved thermal conductance may also contribute to the higher sensitivity of GnP-reinforced composite. This research pointed out the potential of employing GnPs to develop highly sensitive piezoelectric composites for sensing applications.

Superior piezoelectric composite films: taking advantage of carbon nanomaterials

International Nuclear Information System (INIS)

Saber, Nasser; Araby, Sherif; Meng, Qingshi; Hsu, Hung-Yao; Lee, Sang-Heon; Ma, Jun; Yan, Cheng; Xu, Yanan; Azari, Sara; Yu, Sirong

2014-01-01

Piezoelectric composites comprising an active phase of ferroelectric ceramic and a polymer matrix have recently found numerous sensory applications. However, it remains a major challenge to further improve their electromechanical response for advanced applications such as precision control and monitoring systems. We here investigated the incorporation of graphene platelets (GnPs) and multi-walled carbon nanotubes (MWNTs), each with various weight fractions, into PZT (lead zirconate titanate)/epoxy composites to produce three-phase nanocomposites. The nanocomposite films show markedly improved piezoelectric coefficients and electromechanical responses (50%) besides an enhancement of ∼200% in stiffness. The carbon nanomaterials strengthened the impact of electric field on the PZT particles by appropriately raising the electrical conductivity of the epoxy. GnPs have been proved to be far more promising in improving the poling behavior and dynamic response than MWNTs. The superior dynamic sensitivity of GnP-reinforced composite may be caused by the GnPs’ high load transfer efficiency arising from their two-dimensional geometry and good compatibility with the matrix. The reduced acoustic impedance mismatch resulting from the improved thermal conductance may also contribute to the higher sensitivity of GnP-reinforced composite. This research pointed out the potential of employing GnPs to develop highly sensitive piezoelectric composites for sensing applications. (paper)

Note: a high-sensitivity current sensor based on piezoelectric ceramic Pb(Zr,Ti)O3 and ferromagnetic materials.

Science.gov (United States)

He, Wei; Li, Ping; Wen, Yumei; Zhang, Jitao; Yang, Aichao; Lu, Caijiang

2014-02-01

An electric current sensor using piezoelectric ceramic Pb(Zr,Ti)O3 (PZT) sandwiched between two high permeability cuboids and two NdFeB magnets is presented. The magnetic field originating from an electric wire is augmented by the high permeability cuboids. The PZT plate experiences an enhanced magnetic force and generates voltage output. When placed with a distance of d = 5.0 mm from the wire, the sensor shows a flat sensitivity of ∼5.7 mV/A in the frequency range of 30 Hz-80 Hz and an average sensitivity of 5.6 mV/A with highly linear behavior in the current range of 1 A-10 A at 50 Hz.

Understanding the peculiarities of the piezoelectric effect in macro-porous BaTiO3.

Science.gov (United States)

Roscow, James I; Topolov, Vitaly Yu; Bowen, Christopher R; Taylor, John; Panich, Anatoly E

2016-01-01

This work demonstrates the potential of porous BaTiO 3 for piezoelectric sensor and energy-harvesting applications by manufacture of materials, detailed characterisation and application of new models. Ferroelectric macro-porous BaTiO 3 ceramics for piezoelectric applications are manufactured for a range of relative densities, α  = 0.30-0.95, using the burned out polymer spheres method. The piezoelectric activity and relevant parameters for specific applications are interpreted by developing two models: a model of a 3-0 composite and a 'composite in composite' model. The appropriate ranges of relative density for the application of these models to accurately predict piezoelectric properties are examined. The two models are extended to take into account the effect of 90° domain-wall mobility within ceramic grains on the piezoelectric coefficients [Formula: see text]. It is shown that porous ferroelectrics provide a novel route to form materials with large piezoelectric anisotropy [Formula: see text] at 0.20 ≤ α ≤ 0.45 and achieve a high squared figure of merit [Formula: see text] [Formula: see text]. The modelling approach allows a detailed analysis of the relationships between the properties of the monolithic and porous materials for the design of porous structures with optimum properties.

Design and implementation of a versatile and variable-frequency piezoelectric coefficient measurement system.

Science.gov (United States)

Wu, J S; Huang, Y K; Wu, F L; Lin, D Y

2012-08-01

We present a simple but versatile piezoelectric coefficient measurement system, which can measure the longitudinal and transverse piezoelectric coefficients in the pressing and bending modes, respectively, at different applied forces and a wide range of frequencies. The functionality of this measurement system has been demonstrated on three samples, including a PbZr(0.52)Ti(0.48)O(3) (PZT) piezoelectric ceramic bulk, a ZnO thin film, and a laminated piezoelectric film sensor. The static longitudinal piezoelectric coefficients of the PZT bulk and the ZnO film are estimated to be around 210 and 8.1 pC/N, respectively. The static transverse piezoelectric coefficients of the ZnO film and the piezoelectric film sensor are determined to be, respectively, -0.284 and -0.031 C/m(2).

Field-Induced Texturing of Ceramic Materials for Unparalleled Properties

Science.gov (United States)

2017-03-01

Texturing of Ceramic Materials for Unparalleled Properties by...influence over many properties , such as optical transparency, strength, electrical conductivity, and piezoelectricity .19 Highly textured materials are... Ceramic Materials for Unparalleled Properties by Raymond Brennan, Victoria Blair, Nicholas Ku, Krista Limmer, Tanya Chantawansri, Mahesh

Ferroelectric materials for piezoelectric actuators by optimal design

International Nuclear Information System (INIS)

Jayachandran, K.P.; Guedes, J.M.; Rodrigues, H.C.

2011-01-01

Research highlights: → Microstructure optimization of ferroelectric materials by stochastic optimization. → Polycrystalline ferroelectrics possess better piezo actuation than single crystals. → Randomness of the grain orientations would enhance the overall piezoelectricity. - Abstract: Optimization methods provide a systematic means of designing heterogeneous materials with tailored properties and microstructures focussing on a specific objective. An optimization procedure incorporating a continuum modeling is used in this work to identify the ideal orientation distribution of ferroelectrics (FEs) for application in piezoelectric actuators. Piezoelectric actuation is dictated primarily by the piezoelectric strain coefficients d iμ . Crystallographic orientation is inextricably related to the piezoelectric properties of FEs. This suggests that piezoelectric properties can be tailored by a proper choice of the parameters which control the orientation distribution. Nevertheless, this choice is complicated and it is impossible to analyze all possible combinations of the distribution parameters or the angles themselves. Stochastic optimization combined with a generalized Monte Carlo scheme is used to optimize the objective functions, the effective piezoelectric coefficients d 31 and d 15 . The procedure is applied to heterogeneous, polycrystalline, FE ceramics which are essentially an aggregate of variously oriented grains (crystallites). Global piezoelectric properties are calculated using the homogenization method at each grain configuration chosen by the optimization algorithm. Optimal design variables and microstructure that would generate polycrystalline configurations that multiply the macroscopic piezoelectricity are identified.

Design and characterization of piezoelectric ultrasonic motors