• 한국섬유공학회:학술대회논문집
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• 한국섬유공학회 1988년도 학술발표초록집
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• pp.34-34
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• 1988

The pyroelectricity of poly(vinylidenefluoride) films prepared by varying the draw ratio and the poling field was investigated. As the draw ratio and the electric field on poling of the drawn samples increased, so did the pyroelectric coefficient. But the effect of electric field on the pyroelectricity was greater than that of draw ratio. The pyroelectric and piezoelectric activities could be explained by the polarization using the thermally stimulated current. The relation between pyroelectric coefficient and piezoelectric stress constant showed a good linearity.

• 한국광학회지
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• 제8권5호
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• pp.377-381
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• 1997

MgO가 2 mole% 첨가된 LiNbO$_{3}$ 결정을 3 V/cm, 5 V/cm, 7 V/cm의 전기장에서 poling하여, 5 V/cm의 전기장이 최적의 조건임을 제2고조파발생의 온도의존도특성을 관찰하여 알 수 있었다. 결정에 공간적으로 변조된 전기장을 인가하여 온도 위상 정합 모양이 찌그러짐을 관찰하였으며, 이 결과와 잘 일치하는 계산값을 정량적으로 구할 수 있었다. 이것으로부터 제2고조파의 온도위상정합모양을 이용하여 결정의 균일성을 판단할 수 있음을 증명하였다. 5 V/cm로 poling된 단결정의 온도 위상 정합 모양으로부터 온도에 따른 복굴절의 변화율, c-축으로 전기장을 인가하여 변화된 위상 정합 온도로부터 전기장에 따른 복굴절의 변화율을 계산하였다.

• 한국세라믹학회지
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• 제29권10호
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• pp.806-814
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• 1992

The aim of this study was to investigate the change in compressive strength, freacture behavior and degradation of piezoelectric properties with compressive cyclic loading in Pb(Zr, Ti)O3 of tetragonal, morphotropic phase boundary and rhombohedral composition. The highest compressive strength was found in rhombohedral composition. After poling treatment the strength increased by 8.4% and 6.5% in tetragonal and morphotropic phase boundary compositions respectively while changed little in rhombohedral. The increase of compressive strength after poling treatment is believed to be due to the internal stress around grain boundary by domain alginment toward electric field direction in the microstructures having tetragonality and the occurrence of domain switching to the direction perpendicular to electrical field during fracture. Fracture mode relatively change from transgranular to intergranular was observed in the large grain sized tetragonal and morphotropic phase boundary compositions before and after poling but the transgranular fracture mode always remained in the rhombohedral composition. From the X-ray diffractometer analysis the domains parallel to the electric field direction is known to undergo rearrangement during the cyclic loading into random direction that is responsible for the degradation of piezoelectric property.

• 한국재료학회지
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• 제5권2호
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• pp.178-183
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• 1995

본 연구에서는 상온에서 정방성 조성인 $Pb_{0.9888}Sr_{0.012}(Zr_{0.52}Ti_{0.48})O_{3}$계 세라믹스를 소결 후 직류전계 및 코로나를 이용하는 방법으로 소결시편을 분극한 후 분극방법에 따른 시편의 압전특성을 조사하였으며, 열화현상을 평가하기 위한 방법으로 시편의 내부응력의 차이를 조사하였다. 이 결과 코로나 분극방법은 직류분극에 비하여 $30^{\circ}C$정도 저온에서도 최대 Kp값을 얻을 수 있었으며 열화현상이 천천히 진행되었고 절연파괴가 발생하지 않는 등의 장점이 관찰되었다. 그러나 Kp값은 직류분극의 경우가 코로나 분극에 비하여 약 9~10%정도 높은 값을 나타내었다.

• 대한기계학회논문집A
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• 제38권10호
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• pp.1069-1074
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• 2014

본 논문에서는 분극 시간에 따라 압전 페인트 센서의 특성이 어떻게 변하는지 평가하고, 그 결과를 기술하였다. 연구에 사용된 압전 페인트 센서는 유연 압전 재료인 $Pb(Ni_{1/3}Nb_{2/3})O_3-Pb(Zr,Ti)O_2$ (PNN-PZT)와 에폭시 수지를 무게비 1:1로 혼합하여 제작하였다. 센서 시편은 몰드를 사용하여 $40{\times}10{\times}1mm^3$ 크기로 제작하였고, 윗면과 아랫면에 실버 페이스트를 사용하여 전극을 제작하였다. 분극 작업 시 온도는 상온으로, 분극 전계는 4kV/mm 고정한 상태에서 분극 시간을 달리함으로써 분극 조건을 달리하였다. 분극 특성은 충격 망치를 이용하여 충격을 시편에 가했을 때 충격 망치에서 측정되는 힘과 압전 페인트 센서에서 출력되는 전압을 비교하여 살펴보았다. 그 결과, 상온에서 분극 전계가 4kV/mm인 경우, 30분 정도 분극 처리를 한 경우 가장 최적의 분극 조건임을 확인하였다.

• Journal of the Optical Society of Korea
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• 제14권4호
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• pp.420-423
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• 2010

We fabricated 1 mm-thick periodically-poled lithium niobate (PPLN) crystals by using a high-voltage amplifier for standard electric field poling combined with a voltage multiplier. Furthermore, two 1 mm-thick PPLNs were directly bonded to make a 2 mm-thick PPLN. The large aperture allowed broad angular tuning, and a broad spectral range of quasi-phase matched second-harmonic generation can be achieved in a single channel. High-power applications are also expected.

• 전기학회논문지
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• 제57권7호
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• pp.1213-1217
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• 2008

Poling is an important process in fabricating PZT ceramic devices such as filters and resonators and activates piezoelectricity to sintered PZT ceramics. Tolerance of the operating frequency of these devices is tightly required in applications. And a factor to attribute the tolerance is the temperature dependence of the resonance frequency of PZT ceramics. In this paper the relationship of poling strength and temperature dependence of resonance frequency of PZT specimens was studied. The $Pb(Zr_{0.53}Ti_{0.47})O_3$ ceramics were fabricated and the poling strengths were chosen to be 0.5, 1.5, 2.5 and 3.5 [kV/mm]. The dielectric constant of the specimen poled in poling strength 0.5 [kV/mm] was less than that of unpoled specimen and the specimen poled in higher electric field had the higher dielectric constant. (002) peak in X-ray diffraction patterns of the specimens increased as poling strength increased. And the change of resonance frequency of the specimens according to the variation of temperature was measured. Resonance frequency of all specimens increased as the temperature increased. The specimen poled in higher electric field had the smaller positive temperature coefficient of resonance frequency. The effect that temperature coefficient of resonance frequency becomes smaller is obtained when Zr mole in PZT composition equation increase. Controlling the poling strength is believed to be a method to adjust the temperature stability of resonance frequency of the PZT ceramic devices.

• Bulletin of the Korean Chemical Society
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• 제30권4호
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• pp.882-886
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• 2009

The electrode contact poling is one of the efficient tools to induce a stable polar order of nonlinear optical (NLO) chromophores in the solid film. Self-assembled NLO chromophores with high electro-optic (E-O) activities were utilized for quantitative determination of the chromophore order induced under contact poling by spectroscopic changes. We found that NLO chromophores rarely decompose under the high electric field during contact poling. The absorption spectra were de-convoluted into a sum of Gaussian components to separate energy transitions for a binary composite system which contains a secondary guest chromophore AJC146 in the self-assembled chromophore HDFD. Poling efficiency was significantly improved in the binary system compared to the individual components.

• Composites Research
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• 제27권4호
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• pp.146-151
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• 2014

본 연구에서는 분극 전계에 따른 압전 페인트 센서의 특성을 확인하기 위해 충격힘과 분극 전계를 변화시켜 가면서 실험적인 연구를 수행하였다. 페인트 센서 제작을 위해 유연 압전 재료인 $Pb(Ni_{1/3}Nb_{2/3})O_3-Pb(Zr, Ti)O_2$ (PNN-PZT) 파우더와 경화제를 포함하고 있는 에폭시 수지를 중량비 1:1로 혼합 후 몰드를 사용하여 $40{\times}10{\times}1mm^3$ 크기를 같는 시편을 제작 하였다. 이후 시편의 기공을 제거하기 위해 진공 데시케이터를 사용하였다. 분극 작업을 위해 시편의 전극은 실버페이스트를 윗면과 아랫면에 바르고 하루 동안 건조시켜 제작하였다. 분극 작업은 온도는 상온으로, 분극 시간은 30분으로 고정하고 분극 전계를 달리하여 진행되었다. 1 mm의 두께를 갖는 앞전 페인트센서를 제작하여 실험에 사용하였으며, 감도 측정 및 감도 변화는 충격 망치를 사용하여 시편에 충격을 가했을 때 압전 페인트에서 출력되는 전압과 충격 망치에서 출력되는 전압을 측정 후 신호처리 하여 비교하였다. 그 결과 압전 페인트의 민감도에 분극 전계가 미치는 영향에 대해 평가 하였고 그 결과를 기술하였다.

• 한국재료학회지
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• 제33권12호
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• pp.517-524
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• 2023

BaTiO₃-Poly vinylidene fluoride (PVDF) solution was prepared by adding 0~25 wt% BaTiO₃ nanopowder and 10 wt% PVDF powder in solvent. BaTiO₃-PVDF film was fabricated by spreading the solution on a glass with a doctor blade. The output performance increased with increasing BaTiO₃ concentration. When the BaTiO₃ concentration was 20 wt%, the output voltage and current were 4.98 V and 1.03 ㎂ at an applied force of 100 N. However, they decreased when the over 20 wt% BaTiO₃ powder was added, due to the aggregation of particles. To enhance the output performance, the generator was poled with an electric field of 150~250 kV/cm at 100 ℃ for 12 h. The output performance increased with increasing electric field. The output voltage and current were 7.87 V and 2.5 ㎂ when poled with a 200 kV/cm electric field. This result seems likely to be caused by the c-axis alignment of the BaTiO₃ after poling treatment. XRD patterns of the poled BaTiO₃-PVDF films showed that the intensity of the (002) peak increased under high electric field. However, when the generator was poled with 250 kV/cm, the output performance of the generator degraded due to breakdown of the BaTiO₃-PVDF film. When the generator was matched with 800 Ω resistance, the power density of the generator reached 1.74 mW/m². The generator was able to charge a 10 ㎌ capacitor up to 1.11 V and turn on 10 red LEDs.