• Title/Summary/Keyword: Piezoelectric Ceramics

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A Study on the Ferroelectic and Electrooptical Properties of the Transparent Ba(LaS11/2TNbS11/2T)OS13T-PbZrOS13T-PbTiOS13T Ceramics (투광성 Ba(La1/2Nb1/2)O3-PbZrO3-PbTiO3세라믹의 강유전 및 전기광학특성에 관한 연구)

  • 김준수;류기원;박영희;박창엽
    • The Transactions of the Korean Institute of Electrical Engineers
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    • v.41 no.8
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    • pp.858-868
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    • 1992
  • 0.085Ba(LaS11/2TNbS11/2T)OS13T-0.915Pb(ZrS1yTTiS11-yT)OS13T (0.45$\leq$y$\leq$0.65) transparent electrooptic ceramics were fabricated by two-stage sintering method. The structural, ferroelectric and electrooptic properties were investigated varying composition and second sintering time. Also the possibility of application to electrooptic device was studied. If we increase the PbZrOS13T contents, dielectric constants were increased and Curie temperature was decreased. In the composition of 0.55[mol] PbZrOS13T, electromechanical coupling factor and piezoelectric charge constant were the highest values of 43[%] and 173x10S0-12T[C/N], respectively. Mechanical quality factors were decreased with the increasing PbZrOS13T contents. Light transmittance was increased with wavelength when measured from 300[nm] to 900[nm], and with PbZrOS13T contents in the range of 0.50[mol]-0.65[mol], and had the highest value of 67[%] in the composition of 0.65[mol] PbZrOS13T. From the results of ferroelectric hysteresis loop and transmitted light intensity with electric field, the specimens with compositions of 0.65,0.60,0.55[mol] PbZrOS13T were applicable to electrooptic memory device and those with compositions of 0.50,0.45[mol] PbZrOS13T were applicable to linear electrooptic device.

Effects of High-Energy Ball Milling and Sintering Time on the Electric-Field-Induced Strain Properties of Lead-Free BNT-Based Ceramic Composites

  • Nga-Linh Vu;Nga-Linh Vu;Dae-Jun Heo;Thi Hinh Dinh;Chang Won Ahn;Chang Won Ahn;Hyoung-Su Han;Jae-Shin Lee
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.36 no.5
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    • pp.505-512
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    • 2023
  • This study investigated crystal structures, microstructures, and electric-field-induced strain (EFIS) properties of Bi-based lead-free ferroelectric/relaxor composites. Bi1/2Na0.82K0.18)1/2TiO3 (BNKT) as a ferroelectric material and 0.78Bi1/2(Na0.78K0.22)1/2TiO3-0.02LaFeO3 (BNKT2LF) as a relaxor material were synthesized using a conventional solid-state reaction method, and the resulting BNKT2LF powders were subjected to high-energy ball milling (HEBM) after calcination. As a result, HEBM proved a larger average grain size of sintered samples compared to conventional ball milling (CBM). In addition, the increased sintering time led to grain growth. Furthermore, HEBM treatment and sintering time demonstrated a significant effect on EFIS of BNKT/BNKT2LF composites. At 6 kV/mm, 0.35% of the maximum strain (Smax) was observed in the HEBM sample sintered for 12 h. The unipolar strain curves of CBM samples were almost linear, indicating almost no phase transitions, while HEBM samples displayed phase transitions at 5~6 kV/mm for all sintering time levels, showing the highest Smax/Emax value of 700 pm/V. These results indicated that HEBM treatment with a long sintering time might significantly enhance the electromechanical strain properties of BNT-based ceramics.

Comparison of Abnormal Grain Growth Behavior of Lead-Free (Na,K)NbO3-M(Cu,Nb)O3, (M = Ca, Sr, Ba) Piezoelectric Ceramics (비납계 (Na,K)NbO3-M(Cu,Nb)O3, (M = Ca, Sr, Ba) 압전 세라믹의 비정상 결정 성장 거동 비교)

  • Jung, Seungwoon;Lim, Ji-Ho;Jung, Han-Bo;Ji, Sung-Yub;Choi, Seunggon;Jeong, Dae-Yong
    • Korean Journal of Materials Research
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    • v.30 no.7
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    • pp.343-349
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    • 2020
  • NKN [(Na,K)NbO3] is a candidate lead-free piezoelectric material to replace PZT [Pb(Zr,Ti)O3]. A single crystal has excellent piezoelectric-properties and its properties are dependent of the crystal orientation direction. However, it is hard to fabricate a single crystal with stoichiometrically stable composition due to volatilization of sodium during the growth process. To solve this problem, a solid solution composition is designed (Na,K)NbO3-Ba(Cu,Nb)O3 and solid state grain growth is studied for a sizable single crystal. Ceramic powders of (Na,K)NbO3-M(Cu,Nb)O3 (M = Ca, Sr, Ba) are synthesized and grain growth behavior is investigated for different temperatures and times. Average normal grain sizes of individual specimens, which are heat-treated at 1,125 ℃ for 10 h, are 6.9, 2.8, and 1.6 ㎛ for M = Ca, Sr, and Ba, respectively. Depending on M, the distortion of NKN structure can be altered. XRD results show that (NKN-CaCuN: shrunken orthorhombic; NKN-SrCuN: orthorhombic; NKN-BaCuN: cubic). For the sample heat-treated at 1,125 ℃ for 10 h, the maximum grain sizes of individual specimens are measured as 40, 5, and 4,000 ㎛ for M = Ca, Sr, and Ba, respectively. This abnormal grain size is related to the partial melting temperature (NKN-CaCuN: 960 ℃; NKN-SrCuN: 971 ℃; NKN-BaCuN: 945 ℃).

Numerical analysis for electro-mechanical coupling performance of 1-3 type Piezo-composite (1-3형 압전복합체의 전기-기계 결합성능에 대한 수치해석)

  • Shin, H.Y.;Kim, J.H.;Lim, S.J.;Im, J.I.
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.21 no.6
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    • pp.253-258
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    • 2011
  • Electro-mechanical coupling performance ($k_t$) of a 1-3 type Piezo-composite was analyzed numerically using FEM. The calculated physical properties of the PZT ceramics were compared with the experimental data and the accuracy of the numerical method was verified. Also the $k_t$ of the composite was analyzed with the vol% and the material properties of the constitutional parts, and the aspect ratio of the PZT rod. As the simulated results, the $k_t$ increased rapidly when the vol% of the PZT ceramics increased up to 30 vol% and saturated the constant value in the above region. And the composite using the soft matrix polymer than the hard one have the superior $k_t$ characteristics. The $k_t$ was greatly influenced by the aspect ratio of the PZT rod up to 30 vol% of PZT ceramics. To improve the $k_t$ characteristics, it is useful that the composite consist of the relatively flexible polymers and the PZT material having the excellent piezoelectric characteristics.

Preparation and Electrical Properties of Piezoelectric Glass-Ceramics for Application in Hydrophones (하이드로폰용 결정화 유리의 제조 및 전기적 특성)

  • Park, S.S.;Lee, C.H.;Lee, H.;Lee, H.S.;Shon, M.M.;Park, H.C.
    • Korean Journal of Materials Research
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    • v.8 no.12
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    • pp.1146-1151
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    • 1998
  • The crystallization behaviour of perovskite $PbTiO_3$ for the samples heat- treated at various temperatures for various times in the $PbO-TiO_2-A1_2O_3-SiO_2$, glass system has been investigated by the means of X-ray diffraction (XRD) and scanning electron microscopy (SEM) analyses. Higher crystallinity obtained in the sample heat-treated at higher temperature for longer time. With increasing heat-treatment time, dielectric constant of the samples heat-treated at $610^{\circ}C$ and $650^{\circ}C$ increased, but that of the sample heat- treated at $800^{\circ}C$ decreased. Loss tangent of the heat-treated samples was not much influenced by heat-treatment conditions. Piezodielectric charge constant was approximately $1.0\times10^{-12}~8.0$\times$10^{-12}C/N$ in the samples heat-treated at $800^{\circ}C$ for 1h, 2h, and 8h.

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Influence of Additives on Densification of Low-Temperature PZT Ceramics (저온소성용 PZT 세라믹스의 치밀화에 미치는 첨가제의 영향)

  • Park, Yong-Kap
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.8 no.5
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    • pp.995-999
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    • 2007
  • The lead zirconate titanate (PZT) powders were synthesized to make the piezoelectric ceramics in low temperature as low as $900^{\circ}C$. To investigate the influence of additives on sintering of PZT, two kinds of sintering aids were made as follows; $wB_2O_3-xBi_2O_3-zCuO$and LiBiO2-CuO. The sintering aid, $1{\sim}3$ wt.% $LiBiO_2-CuO$, was added into these PZT powders and the specimens were fired at temperature in the range of $800{\sim}1200^{\circ}C$. The highest density was shown in the specimen with 1 wt.% $LiBiO_2-CuO$ as additive at temperature of $900^{\circ}C$. The sintered specimen were analyzed by X-ray diffraction(XRD) and scanning electron microscopy (SEM) was utilized to observe the microstructure, especially the densified morphology of specimens. In the XRD pattern, the well-crystallized PZT phase could be obtained in consequence of firing at $900^{\circ}C$. The scanning electron microscopy(SEM) was utilized to observe the structure of specimens after firing at $900^{\circ}C$. The densified perovskite structure of $PbZrTiO_3$ could be obtained by sintering at temperature as low as $900^{\circ}C$. The high sinterability of PZT ceramics was attributed to the low formation temperature of the liquid phase of additives.

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우주환경하에서의 진동자의 주파수 변화 측정에 의한 질량 측정 시스템 및 방법

  • Kim, Youn-Kyu;Kim, Jong-Woo;Kim, Kwong-Sik;Choi, Gi-Hyuk
    • Aerospace Engineering and Technology
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    • v.4 no.2
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    • pp.216-219
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    • 2005
  • In this study, we will explain the design, test results and analysis of system for measuring the small mass in the microgravity environment. It is so difficult to measure the mass by sensing the gravity as the ground in the microgravity environment. The suggested method is to measure the resonance frequency of a sample. The resonance frequency may be measured as a function of mass. If we know the resonance frequency of the mass, we can guess the mass by detecting the resonance frequency. Piezoelectric ceramics have the characteristics that resonance frequency is changed by total mass which are its mass and the attached mass. This system have some problems but we verified that we can measure the unknown mass using the resonance frequency as the mass.

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Design and Acoustic Properties of Acoustic Device with Metal-Piezoceramic Circular Plate (금속-압전세라믹스로 구성된 음향소자의 설계 및 음향특성)

  • Go Young-Jun;Lee Sang-Wook;Nam Hyo-Duk;Chang Ho-Gyeong
    • Proceedings of the Acoustical Society of Korea Conference
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    • spring
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    • pp.275-278
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    • 2000
  • In this study, the acoustic transducer of a thin circular disc-type with PZT/Metal was designed. The dielectric and piezoelectric properties of $0.5wt\%$ $MnO_2$ and NiO doped 0.1Pb($Mg_{1/3}$$Nb_{2/3}$)$O_3$-$0.45PbTiO_3$-$0.45PbZrO_3$ ceramics were investigated aiming at acoustic transducer applications. The vibration characteristics for the laminated circular plate was analyzed for the various thickness and diameter of the piezoceramic layer and metal layer. The acoustic characteristics which is radiated from the acoustic transducer within the finite space was simulated using the finite element method. It has been observed that the characteristics of the sound pressure ard impedance response calculated for the various models of the size and geometry of acoustic transducer.

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The Study of the Properties of $Pb(Mg_{0.15} W_{0.15})Ti_{0.35}-Zr_{0.35}O_3$ Ceramics Modified with $La_2O_3$, $Nb_2O_5$ and $Al_2O_3$ (첨가제에 따른 $Pb(Mg_{1/2} W_{1/2}) O_3-PbTiO_3-ObZrO_3$ 고용체의 특성에 대한 연구)

  • 안영필;황학인;홍진녕
    • Journal of the Korean Ceramic Society
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    • v.22 no.2
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    • pp.17-24
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    • 1985
  • In the composition of $Pb(Mg_{0.15} W_{0.15})Ti_{0.35}-Zr_{0.35}O_3$ the effect of particle size on PbO vaporization were measured, . The initial step of discontinuous vaporization of unreated PbO during the calcining process was depended on the particle size. All additives $La_2O_3Nb_2O_5$ and $Al_2O_3$ inhibited the grain growth of the composition $Pb(Mg_{0.15} W_{0.15})Ti_{0.35}-Zr_{0.35}O_3$ +2wt% excess PbO. The dielectric and piezoelectric properties of the composition $Pb(Mg_{0.15} W_{0.15})Ti_{0.35}-Zr_{0.35}O_3$ were improved by the addition of 2wt% excess PbO and proper additive. The electromechanical planar coupling factor of 0.65 and mechnical quality factor of 390 could be obtained by adding 5wt% $Nb_2O_5$ to the composition 2wt% excess PbO+$Pb(Mg_{0.15} W_{0.15})Ti_{0.35}-Zr_{0.35}O_3$.

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Development of Acoustic Emission(AE) Sensor for Prognosis Detection of Bearing Fault (베어링 고장 예후검출을 위한 음향 방출(AE)센서 개발)

  • Lee, Chibum;Kim, Gyeongwoo;Park, Yeong-Il
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.24 no.6
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    • pp.429-436
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    • 2014
  • Most mechanical systems are now operating consistently and getting faster due to the development of automation systems. Peoples' dependence on machines have increased as when problems occur within the mechanical system, personal injury and production loss may come as a result, as most of the mechanical system's malfunctions are caused by the failure of the rotational bearing. What we need now is a maintenance system that can warn us when it detects abnormal conditions before significant damage occurs to the bearing. In this study, we have developed an acoustic emissions sensor that can figure if the bearing works under the normal condition. With this acoustic emissions sensor, we can inspect the bearing for defects by using the Heterodyne technique, which converts the ultrasound signal into audio, as a signal conditioning process.