• Transactions on Electrical and Electronic Materials
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• v.12 no.6
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• pp.249-252
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• 2011

We investigated the low firing of $Li_2CO_3$ added $0.2Pb(Mg_{1/3}Nb_{2/3})O_3$ - 0.3Pb($Fe_{1/2}Nb_{1/2}$) - $0.5Pb(Zr_{0.475}Ti_{0.525})O_3$ (PMN-PFN-PZT) ceramics and multilayer actuators (MLAs) using Ag inner electrodes. It was found that 0.1 wt% $Li_2CO_3$ was quite effective in lowering the sintering temperature of PMN-PFN-PZT ceramics from $1,100^{\circ}C$ down to $900^{\circ}C$ without deteriorating their piezoelectric ceramics ($d_{33}$ = 425 pC/N and $k_p$ = 61.9%). However, excess $Li_2CO_3$ up to 0.3 wt% brings about unwanted problems such as the formation of a $LiPbO_2$ secondary phase and subsequent degradation in the piezoelectric properties. Using 0.1 wt% $Li_2CO_3$ added PMN-PFN-PZT ceramics, MLAs with Ag inner electrodes were successfully fabricated, resulting in a normalized strain of 580 pm/V at an electric field of 1.5 kV/mm.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.07a
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• pp.873-876
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• 2000

Characteristics of piezoelectric thick films prepared by screen printing method were investigated. The piezoelectric thick films were printed using Pb(Mg,Nb)O$_3$-Pb(Zr,Ti)O$_3$system. The lower electrodes were coated with various thickness of Ag-Pd by screen printing to investigate the effect as a diffusion barrier and deposited with Pt by sputtering on Ag-Pd. The ceramic paste was prepared by mixing powder and binder with various ratios using three roll miller. The fabricated thick films were burned out at 650$^{\circ}C$ and sintered at 950$^{\circ}C$ in the O$_2$condition for each 20, 60min after printing with 350mesh screen. The thickness of piezoelectric thick film was 15∼20 $\mu\textrm{m}$ and the Ag-Pd electrode acted as a diffusion barrier above 3 $\mu\textrm{m}$ thickness. When the lower electrode Ag-Pd was 6 $\mu\textrm{m}$ and the piezoelectric thick films were sintered by 2nd step (650$^{\circ}C$/20min and 950$^{\circ}C$/1h) using paste mixed Pb(Mg,Nb)O$_3$-Pb(Zr,Ti)O$_3$$.$ MnO$_2$+ Bi$_2$O$_3$. V$_2$O$\_$5/ and binder in the ratio of 70:30, the remnant polarization of thick film was 9.1 ${\mu}$C /cm$^2$.

• Analytical Science and Technology
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• v.10 no.6
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• pp.439-444
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• 1997

Twelve kinds (1set) standard materials of chemical ingredients of lead zirconate titanate[$Pb(ZrTi)O_3$] have been developed in order to determine fast and accurate measurement of X-ray fluorescence spectrometry. Especially, we used diluted(ahout sixteen times) filling compound($Li_2B_4O_7/LiBO_2=4/1$) to consider removal effect of matrix, storage convenience, and homogenous characteristics. As a result from the four different laboratories, we obtained extremly good agreement about the standard curve on twelve standard materials which containing eleven elements, PbO, $ZrO_2$, $TiO_2$, SrO, $WO_3$, $La_2O_3$, $Cr_2O_3$, MgO, $Nb_2O_5$, and $MnO_2$. The correlation factor of standard curve was over 0.998. However, ZnO has relatively low correlation factor, 0.977, because the concentration was 10ppm lower than other original materials. This analysis reveals that ZnO has shown the poor linearity as well as low fluorescence intensity. In present work, XRF standard materials are useful for determining a rapid and accurate results for major and minor elements concentration among PZT.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.167-167
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• 2013

최근에 산화물 형광체는 황화물 형광체에 비해 높은 화학적 안정성을 나타내기 때문에 백색 발광 다이오드, 전계방출 디스플레이와 플라즈마 디스플레이 패널에 그 응용성을 넓히고 있다. 마그네슘 니오베이트(magnesium niobate, MgNb2O6)는 우수한 유전 특성(상대 유전상수=18.4)을 나타내기 때문에 마이크로파 유전체로 응용 가능하며, 단일상 릴랙서 페라브스카이트(relaxor perovskite) Pb(Mg1/3Nb2/3)O3을 합성하기 위한 전구체 (precursor)로 널리 사용되고 있으며, 나이오븀산염 이온에서 다양한 색상을 방출하는 활성제 이온으로 효율적인 에너지 전달이 일어남으로써 Sm3+, Dy3+, Eu3+와 같은 희토류 이온의 좋은 모체 격자로 개발할 수 있다. 본 연구에서는 마그네슘 니오베이트 MgNb2O6 모체 결정에 다양한 활성제 이온, 즉 Eu3+, Sm3+, Dy3+, Tb3+를 선택적으로 주입하여 발광 효율이 높은 천연색 형광체를 합성하고자 한다. 특히, 모체 결정에 주입되는 활성제 이온 주위의 국소적인 환경이 반전 대칭에서 변형되는 척도를 조사하여 활성제의 주 발광 파장의 세기가 최대가 되는 최적의 조건을 결정하고자 한다. Mg1-1.5xNb2O6:REx3+ 형광체 분말 시료는 초기 물질 MgO, Nb2O5와 희토류 이온을 화학 반응식에 맞게 정밀 저울로 측량하여 플라스틱 용기에 ZrO2 볼과 함께 넣고, 소정의 에탄올을 채운 뒤 밀봉하고서, 300 rpm의 속도로 20시간 볼밀 (ball-mill) 작업을 수행하였다. 그 후, 체(sieve)로 ZrO2 볼을 걸러낸 다음에 혼합된 용액을 각 비커에 담아서 $40^{\circ}C$의 건조기에서 24시간 건조하였고, 건조된 시료를 막자 사발에 넣고 잘게 갈고 80 ${\mu}m$의 체로 걸러낸 후에, 알루미나 도가니에 활성제 이온별로 각각 담아, 전기로에 장입하여 매분당 $5^{\circ}C$의 비율로 온도를 상승시켜 $350^{\circ}C$에서 5시간 동안 하소 공정을 실시한 후에, 온도를 계속 일정한 율로 증가시켜 $1,200^{\circ}C$에서 5시간 동안 소성하여 합성하였다. 합성된 형광체 분말의 결정 구조는 $Cu-K{\alpha}$ 복사선(파장: 1.5406)을 사용하여 X-선회절장치로 측정하였으며, 형광체의 표면 형상은 전계형 주사전자현미경으로 관측하였다. 흡광와 발광스펙트럼은 제논 램프를 광원으로 갖는 형광 광도계를 사용하여 측정하였다. 모체 결정에 활성제 이온 Eu3+, Sm3+, Dy3+, Tb3+가 도핑된 형광체 분말은 각각 적색, 주황색, 황색, 녹색 발광이 관측되었다. 각 발광 스펙트럼과 결정 입자의 크기와 형상 사이의 상호 관계를 조사하였다. 실험 결과로부터, 각 형광체의 발광 파장은 활성제 이온의 종류 와 서로 밀접하게 관련되어 있으며, 형광체 시료 합성시 활성제 이온의 농도를 선택적으로 조절함으로써 발광의 세기를 제어할 수 있음을 확인하였다.

• Journal of the Korean Ceramic Society
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• v.55 no.2
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• pp.166-173
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• 2018

In order to investigate the effect of Mn on the dielectric and piezoelectric properties of PMN-PT [$Pb(Mg_{1/3}Nb_{2/3})O_3-PbTiO_3$], four different types of 71PMN-29PT samples were prepared using the solid-state single crystal growth (SSCG) method: (1) Undoped single crystals, (2) undoped polycrystalline ceramics, (3) Mn-doped single crystals, and (4) Mn-doped polycrystalline ceramics. In the case of single crystals, the addition of 0.5 mol% Mn to PMN-PT decreased the dielectric constant ($K_3{^T}$), piezoelectric charge constant ($d_{33}$), and dielectric loss (tan ${\delta}$) by about 50%, but increased the coercive electric field ($E_C$) by 50% and the electromechanical quality factor ($Q_m$) by 500%, respectively. The addition of Mn to PMN-PT induced an internal bias electric field ($E_I$) and thus specimens changed from piezoelectrically soft-type to piezoelectrically hard-type. This Mn effect was more significant in single crystals than in ceramics. These results demonstrate that Mn-doped 71PMN-29PT single crystals, because they are piezoelectrically hard and simultaneously have high piezoelectric and electromechanical properties, have great potential for application in fields of SONAR transducers, high intensity focused ultrasound (HIFU), and ultrasonic motors.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.07a
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• pp.350-351
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• 2005

In this study, in order to develop the low temperature sintering multilayer piezoelectric transformer, PMW-PMN-PZT system ceramics were manufactured with the addition of sintering aids, and their dielectric and piezoelectric characteristics were investigated. At the composition ceramics sintered at $900^{\circ}C$, dielectric constant(${\varepsilon}r$), electromechanical coupling factor(kp) and mechanical quality factor(Qm) showed the optimal value of 1043, 0.44 and 793, respectively, for multilayer piezoelectric transformer application.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.14 no.1
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• pp.12-19
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• 2001

In this study, the physical properties of the piezoelectric sounder with metal-piezoelectric ceramics were analyzed. The dielectric and piezoeletric 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 acoustic characteristics of a thin circular disc-type with metal-piezoceramics have been investigated. Also, the acoustic characteristics for the geometrical form of case were investigated. The piezoelectric sounder with 200kHz resonant frequency and 20kHz bandwidth was designed by considering the sharp directivity and the sound pressure.

• Proceedings of the KIEE Conference
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• 1997.07d
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• pp.1537-1539
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• 1997

In this study, the dielectric properties of $Pb(Mg_{1/3}Nb_{2/3})O_3-PbTiO_3$ Ceramics have been investigated as a addition of the amount of $MnO_2(0{\leq}x{\leq}0.9wt%)$. The Temperature-dependant dielectric characteristics of 0.9PMN-0.1PT relaxor ferroelectric system were improved by enhencing the extent of the diffuse phase transition(DPT). The maximum dielectric permittivity decreased by substitution $MnO_2$ and the dielectric loss decreased with increasing $MnO_2$ substitution amount. It is expected decreasing in inner heat energy for temperature with increasing $MnO_2$ substitution.

• Journal of the Korean institute of surface engineering
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• v.36 no.5
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• pp.413-417
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• 2003

The effect of 0-0.7 ㏖% addition of $Cr_2$$O_3$on the dielectric, pyroelectric, and piezoelectric properties were studied in the (Mg$0.7Pb_{1}$$3/Nb_{2}$3/)$O_3$-$0.3PbTiO_3$(0.7PMN-0.3PT) ceramics with composition near the morphotropic phase boundary. The dielectric constant and loss of the ceramics samples were measured as a function of temperature at various frequencies (0.1-100 KHz). The pyroelectric coefficient was measured by using the Byer-Roundy method as a function of temperature. Dielectric, pyroelectric, and piezoelectric constant achieved the maximum values of 0.4 ㏖% $Cr_2$$O_3$The transition temperature is continuously shifted to lower temperature with an increase of a small amount of $Cr_2$$O_3$.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.06a
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• pp.300-300
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• 2006

일반적으로 PZT계 세라믹스는 높은 결정격자 이방성을 가지고 있으며, 우수한 압전특성을 가지고 있다. 이러한 특성을 보이기 위해서는 높은 온도($1200^{\circ}C$)에서 소결을 해야하기 때문에 PbO의 휘발로 인하여 환경문제가 야기되고 있다. 이러한 문제를 해결하기 위해서 Li, Na같은 액상소결제를 첨가시켜 소결온도를 낮추는 연구를 하고 있다. 본 연구에서는 $Pb(Mn_{1/3}Nb_{2/3})O_3$-PZT세라믹스가 갖는 높은 결정격자 이방성을 유지시키고, 저온소결시 압전 및 유전특성을 향상시키기 위해서 $Pb(Mg_{1/2}W_{1/2})O_3$를 치환시켜 attrition milling 시간에 따른 PWM-PMN-PZT세라믹스의 압전특성을 조사하였다.