• Title/Summary/Keyword: Piezoelectric Single Crystal

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Micro Ultrasonic Elliptical Vibration Cutting (II) Ultrasonic Micro V-grooving Using Elliptical Vibration Cutting (미세 초음파 타원궤적 진동절삭 (II) 타원진동 절삭운동을 이용한 미세 홈 초음파 가공)

  • Kim Gi Dae;Loh Byoung-Gook;Hwang Kyung-Sig
    • Journal of the Korean Society for Precision Engineering
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    • v.22 no.12 s.177
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    • pp.198-204
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    • 2005
  • For precise micro V-grooving, ultrasonic elliptical vibration cutting (UEVC) is proposed using two parallel piezoelectric actuators, which are energized by sinusoidal voltages with a phase difference of 90 degrees. Experimental setup is composed of stacked PZT actuators, a single crystal diamond cutting tool, and a precision motorized xyz stage. It is found that the chip formed in the process of UEVC is discontinuous because of the periodic contacts and non-contacts occurring between the tool and workpiece. It is experimentally observed that the cutting force in the process of UEVC significantly reduces compared to the ordinary non-vibration cutting. In addition, the creation of burr during UEVC is significantly suppressed, which is attributable to the decrease in the specific cutting energy.

Periodic domain formation in $>LiNbO_3$ single crystals during growth

  • Park, Jong-Koen
    • Proceedings of the Korea Association of Crystal Growth Conference
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    • 1998.06a
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    • pp.23-26
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    • 1998
  • The domain formation phenomena of {{{{ { LiLbO}_{ 3} }}}} crystals was investigated and the method for the periodic domain formation in {{{{ { LiLbO}_{ 3} }}}} single crystals during growth was proposed in this study. The strees-induced domain formation mechanism was proposed and explained. The strong piezoelectric effect of{{{{ { LiLbO}_{ 3} }}}} at elevated temperature would be the direct driving force for the inversion of the tensile component of the internal stresses can inverse the original direction of the spontaneous polarization.

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Fast Abnormal Grain Growth Behavior and Electric Properties of Lead-Free Piezoelectric (K,Na)NbO3-Ba(Cu,Nb)O3 Grains through Transient Liquid Phase (과 액상 형성에 의한 비납계 압전 (Na,K)NbO3-Ba(Cu,Nb)O3 결정립의 비정상 성장 거동 및 전기적 특성)

  • Lim, Ji-Ho;Lee, Ju-Seung;Lee, SeungHee;Jung, Han-Bo;Park, Chun-kil;Ahn, Cheol-Woo;Yoo, Il-Ryeol;Cho, Kyung-Hoon;Jeong, Dae-Yong
    • Korean Journal of Materials Research
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    • v.29 no.4
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    • pp.205-210
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    • 2019
  • $Pb(Zr,Ti)O_3$ (PZT) is used for the various piezoelectric devices owing to its high piezoelectric properties. However, lead (Pb), which is contained in PZT, causes various environment contaminations. $(K,Na)NbO_3$ (NKN) is the most well-known candidate for a lead-free composition to replace PZT. A single crystal has excellent piezoelectric-properties and its properties can be changed by changing the orientation direction. It is hard to fabricate a NKN single crystal due to the sodium and potassium. Thus, $(Na,K)NbO_3-Ba(Cu,Nb)O_3$ (NKN-BCuN) is chosen to fabricate the single crystal with relative ease. NKN-BCuN pellets consist of two parts, yellow single crystals and gray poly-crystals that contain copper. The area that has a large amount of copper particles may melt at low temperature but not the other areas. The liquid phase may be responsible for the abnormal grain growth in NKN-BCuN ceramics. The dielectric constant and tan ${\delta}$ are measured to be 684 and 0.036 at 1 kHz in NKN-BCuN, respectively. The coercive field and remnant polarization are 14 kV/cm and $20{\mu}C/cm^2$.

A promising new piezoelectric material -Langasite and its related compounds-

  • Kawanaka, Hiroyuki;Takeda, Hiroaki;Shimamura, Kiyoshi;Onozato, Norio;Fukuda, Tsuguo
    • Proceedings of the Korea Association of Crystal Growth Conference
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    • 1997.06a
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    • pp.145-145
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    • 1997
  • Recent progress of electric technology requires new piezoelectric crystals having superior properties such as zero temperature coefficients and large electromechanical coupling factors. We have developed a series of new leading chandidates, La$_3$Ga5SiO14(langasite, LGS), La3Nb0.5Ga5.5O14(LNG), La3Ta0.5O14(LTG), to satisfy those requirements. High quality LGS, LNG and LTG single crystals, with dimensions of 2 inches in diameter, were successfully grown by the Czochralski method at a pulling rate of 1mm/h. Since no variation of chemical composition was observed when whole melt in a crucible was crystallized, congruency of these compositions was confirmed. Physical constants such as elastic constants, dielectric constants and piezoelectric constants were measured. Filters and oscillators made of grown LGS, LNG and LTG single crystals showed superior properties such as three times wider passband than that of quartz, low insertion loss and easy processing, Langasite family crystals were shown to be superior materials to other known materials such as quartz, LiTaO$_3$, $\alpha$-AlPO$_4$ and Li$_2$B$_4$O7.

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Development of a Multi-Layer Actuator With Piezoelectric Single Crystals for an Implantable Hearing Aid (압전 단결정 재료를 이용한 이식형 인공중이용 적층 액츄에이터 개발)

  • Lee, Sang-gu;Roh, Yong-rae;Seon, Joo-heon
    • The Journal of the Acoustical Society of Korea
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    • v.24 no.3
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    • pp.127-132
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    • 2005
  • Transducers for implantable hearing aids need to be small and to have good performance in frequency responses and vibration properties. From this viewpoint, we Proposed a multi-layer actuator with the piezoelectric single crystal, PMN-PT. for the implantable hearing aid. and verified its adequacy through finite element analyses and experiments. PMN-PT multi-layer actuator samples were fabricated by stacking fourteen layers of the PMN-PT crystal. Each layer were $0.2{\cal}mm$ thick and the actuator sample was $2.8{\cal}mm$ thick in total. We evaluated the performance of the PMN-PT actuator through impedance analyses and vibration displacement measurements, and compared the result with that of a PZT actuator. Results of all the process confirmed the feasibility of the PMN-PT actuator as a good transducer for an implantable hearing aid.

Analysis and verification of the characteristic of a compact free-flooded ring transducer made of single crystals (압전단결정을 이용한 소형 free-flooded ring 트랜스듀서의 성능 특성 예측 및 검증)

  • Im, Jongbeom;Yoon, Hongwoo;Kwon, Byungjin;Kim, Kyungseop;Lee, Jeongmin
    • The Journal of the Acoustical Society of Korea
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    • v.41 no.3
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    • pp.278-286
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    • 2022
  • In this study, a 33-mode Free-Flooded Ring (FFR) transducer was designed to apply piezoelectric single crystal PIN-PMN-PT, which has high piezoelectric constants and electromechanical coupling coefficient. To ensure low-frequency high transmitting sensitivity characteristics with a small size of FFR transducer, the commercial FFR transducer based on piezoelectric ceramics was compared. To develop the FFR transducer with broadband characteristics, a piezoelectric segmented ring structure inserted with inactive elements was applied. The oil-filled structure was applied to minimize the change of acoustic characteristics of the ring transducer. It was verified that the transmitting voltage response, underwater impedance, and beam pattern matched the finite element numerical simulation results well through an acoustic test. The difference in the transmitting voltage response between the measured and the simulated results is about 1.3 dB in cavity mode and about 0.3 dB in radial mode. The fabricated FFR transducer had a higher transmitting voltage response compared to the commercial transducer, but the diameter was reduced by about 17 %. From this study, it was confirmed that the feasibility of a single crystal-applied FFR transducer with compact size and high-power characteristics. The effectiveness of the performance prediction by simulation was also confirmed.

High $T_c/E_c$ PMN-PZT Single Crystals for Piezoelectric Actuator and Transducer Applications : Bridgman PMN-PT Crystals vs. SSCG PMN-PZT Crystals (압전 액츄에이터와 트랜스듀서용 고효율 압전 PMN-PZT 단결정 개발 : 브릿지만법 PMN-PT 단결정과 고상단결정 성장법 PMN-PZT 단결정 비교)

  • Lee, Ho-Yong;Lee, Sung-Min;Kim, Dong-Ho
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2009.06a
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    • pp.17-17
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    • 2009
  • Piezoelectric single crystals in the ternary MPB PMN-PZ-PT system with high $T_cs$ ($T_c$ > $200\sim300^{\circ}C$) and $E_cs$($E_c$>5~10 kV/cm) were fabricated by the cost-effective solid-state crystal growth (SSCG) technique. Chemically uniform PMN-PZT single crystals were successfully grown up to 60 mm by the SSCG method and their dielectric and piezoelectric properties characterized. Compared to Bridgman PMN-PT single crystals, the high $T_c/E_c$ PMN-PZT single crystals were found to exhibit a much wider usage range with respect to electric field as well as temperature, and thus become best candidates for medical transducers, actuators, and naval applications.

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Characterization of the Material Properties of 0.68Pb ($Mg_{1}$3/$Nb_{2}$3/)$O_3$-0.32PbT$iO_3$ Single Crystals Grown by the Solid-State-Crystal-Growth Method (고상단결정법으로 성장시킨 0.68Pb ($Mg_{1}$3/$Nb_{2}$3/)$O_3$-0.32PbT$iO_3$ 압전단결정의 물성평가)

  • 이상한;노용래
    • The Journal of the Acoustical Society of Korea
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    • v.23 no.2
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    • pp.103-108
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    • 2004
  • In this paper, all the materials constants of the PMN-32%PT single crystals grown by the solid state crystal growth method were measured by the resonance method. PMN-PT crystals of tetragonal symmetry have six elastic constants, three piezoelectric constants and two dielectric constants for their independent material constants. These materials constants were extracted from six sets of crystal samples of each different geometry to have different vibration modes respectively. Measured results showed that the crystal has larger electromechanical coupling factor k/sub 33/ (∼86%) and piezoelectric constant d/sub 33/ (∼1200pC/N) than conventional piezoceramics. Validity of the measurement was confirmed through comparison of the results with the impedance spectrum from finite element analysis of the samples and the results measured with a commercial do meter.

Design and Fabrication of a 1.75D Ultrasonic Transducer (1.75D 초음파 트랜스듀서의 설계 및 제작)

  • Lee, Wonseok;Roh, Yongrae
    • The Journal of the Acoustical Society of Korea
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    • v.32 no.3
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    • pp.199-207
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    • 2013
  • In this paper, a $64{\times}8$ channel 1.75D ultrasonic transducer made of piezoelectric single crystals was designed, fabricated, and evaluated. First, a structure of the transducer was selected to be suitable for wiring on a planar array, and components were fabricated to correspond to the structure. Detailed structure of the transducer was designed through finite element analyses. As main performance factors, the crosstalk between neighboring elements was reduced through the control of kerf width and material, and desired frequency bandwidth of the transducer was achieved by designing the optimal thicknesses of the piezoelectric single crystal and matching layers. An experimental prototype of the transducer was fabricated following the design, and its performance was measured. Then the experimental results were compared with those of the finite element analysis, which led to the evaluation of the transducer developed in this work.