• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.11
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• pp.1174-1177
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• 2004

The dielectric and piezoelectric properties of silver added 0.96 Pb(Z $r_{0.52}$ $Ti_{0.48}$) $O_3$-0.04 Pb(Mn,W,Sb,Nb)$_3$ ceramics were examined. By varying the contents of silver(0.0, 0.4, 1.0 mol%), the effect of silver addition on PZT-PMWSN ceramics was investigated at various sintering temperature(900, 1000, 1100 $^{\circ}C$). As increasing silver contents, the relative dielectric constant was increased and sinterability was enhanced. At the specimen with 0.4 mol% Ag and sintered at 1000 $^{\circ}C$, electromechanical coupling factor( $k_{p}$), mechanical quality factor( $Q_{m}$), dielectric constant($\varepsilon$$_{r}$) and dielectric loss were 0.502, 811, 991, 0.006, respectively. The results showed that the PZT-PMWSN/Ag composites have enhanced piezoelectic and dielectric properties and sintering temperature was lowered.red.

• Journal of the Microelectronics and Packaging Society
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• v.8 no.1
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• pp.27-32
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• 2001

The effect of $V_2O_5$, a donor-type dopant on the degradation of quality factor of ($Zr_{0.8}, Sn_{0.2})TiO_4$was compared with Ta$_2$O$_{5}$ doped ($Zr_{0.8}, Sn_{0.2})TiO_4$ in terms of microstructure, electrical conductivity, and oxidation state of the dopant. It is well known that the addition of the donor type species such as $Ta_2O_5,Nb_2O_5, Sb_2O_5, WO_{3}$, increases the quality factor of ($Zr_{0.8}, Sn_{0.2})TiO_4$due to decrease the oxygen vacancy concentration. Unlike other dopants, however, the addition of $V_2O_5$ decreased the quality factor. The degradation of quality factor of ($Zr_{0.8}, Sn_{0.2})TiO_4$was resulted from the formation of grain boundary phase and $V_2O_5$rich fiber shaped secondary phase, and the increasing the oxygen vacancy concentration due to unstability of oxidation state of vanadium ions in ($Zr_{0.8}, Sn_{0.2})TiO_4$ceramic.c.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.149-152
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• 2001

A great deal of attention has been focused on the application of miniaturized piezoelectric transformers to the low power source for the microsystem. The dielectric and piezoelectric properties of Pb(Mn,W,Sb,Nb)O$_3$-Pb(Zr,Ti)O$_3$ ceramics have been investigated on different calcination(750$^{\circ}C$∼950$^{\circ}C$) and sintering(1100$^{\circ}C$∼1300$^{\circ}C$) temperatures. The perovskitic phase was formed by the solid phase reaction of the oxides. Anisotropic (k$\sub$t/k$\sub$p/) properties of electromechanical coupling coefficient and piezoelectric coefficient have been proven to be depending on processing temperatures. The value of electromechanical coupling factor of K$\sub$p/>0.51 and a mechanical quality factor of Q$\sub$m/>2000 were obtained. The piezoelectric transformer was prepared using this ceramics with the composition of Pb(Mn,W,Sb,Nb)O$_3$-Pb(Zr,Ti)O$_3$ We studied the influence of different processing temperature on the microstructure and piezoelectric properties of complex PZT-based ceramics. and the characteristic of piezoelectric transformer.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.19 no.3
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• pp.222-227
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• 2006

RAINBOW(Reduced And Internally Biased Oxide Wafers) are a new class of high-displacement, piezoelectric actuator produced by selectively removing oxygen from one surface of ceramic using a high-temperature chemical reduction process. In this paper, RAINBOW actuator materials of $0.4Pb(Ni_{1/3}Nb_{2/3})O_3-0.6Pb(Zr_{x}Ti_{1-x})O_3$ ceramics were prepared. Its dielectric and piezoelectric properties were investigated in the vicinity of MPB. The piezoelectric properties showed the maximum value of ${\epsilon}r$ = 4871, $d_{33}$ = 610 ($10^{-12}$ m/V), $d_{31}$ = -299 ($10^{-12}$ m/V), $k_{33}$ = $71\%$, Qm = 70, in $0.4Pb(Ni_{1/3}Nb_{2/3})O_{3}-0.6Pb(Zr_{405}Ti_{595})O_3$ composition sintered at $1250^{\circ}C$. The strain - electric field characteristics of RAINBOW actuator were significantly improved comparison with the conventional bulk actuator. The prepared RAINBOW actuator showed about $390\;{\mu}m/100\;V$ displacement.

• Proceedings of the Materials Research Society of Korea Conference
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• 2012.05a
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• pp.94.2-94.2
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• 2012

에너지 하베스터에 적용 가능한 $0.72Pb(Zr_{0.47}Ti_{0.53})O_3-0.28Pb((Ni_{0.55}Zn_{0.45})_{1/3}Nb_{2/3})O_3$ (PPZNN) 후막세라믹의 구조적 압전 특성을 조사하였다. $850^{\circ}C$에서 하소를 마친 파우더를 72시간 볼 밀링 처리한 후, 테잎 캐스팅 공정을 이용하여 0.3mm의 두께로 PPZNN 압전 세라믹을 제조하였다. $900^{\circ}C$에서 $1200^{\circ}C$까지 다양한 온도에 소결하여 온도가 증가될수록 정방형 구조로 상전이 거동하는 모습을 보였으며, 특히 $1050^{\circ}C$에서 소결된 PPZNN후막 세라믹은 이차상이 없는 고밀도의 미세구조가 관찰되었다. $d_{33}$=440 pC/N 그리고 kp = 0.46의 우수한 압전 특성을 보였으며, 에너지 변환 성능을 나타내는 $d33{\cdot}g33$ 값은 약 $20439{\times}10^{-15}\;m^2/N$ 로 매우 우수하였다. PPZNN후막 세라믹을 유니몰프 켄틸레버 형태로 제작하여 발전 평가하였을 때 저항이 470 $k{\Omega}$에서 969 ${\mu}W$ (4930 ${\mu}W/cm^3$)로 관찰되었다. PPZNN 후막 압전 세라믹은 향후 압전에너지 하베스터 소재로 다양한 응용분야에 사용될 것으로 예상된다.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.29 no.8
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• pp.466-469
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• 2016

In this study, in order to develop composition ceramics for Acoustic Emission (abbreviated as AE) sensor application, the PZT system ceramics was fabricated by conventional solid state reaction method. When x=0.48, the density, electromechanical coupling factor($k_p$), piezoelectric coefficient $d_{33}$ and piezoelectric voltage constant $g_{33}$ of the maximum values of $7.857g/cm^3$, 0.51, 190[pC/N], 52[$10^{-3}mV/N$] were obtained, respectively, suitable for AE sensor.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.07a
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• pp.357-360
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• 2000

Ferroelectric 0.05PZN-xPZT(90/10)-(0.95-x)PZT(10/90) (x=0.65, 0.85) specimens were fabricated by the mixed-oxide method and cold-pressing method using sol-gel derived PZT(90/10) and PZT(10/90) powders. All specimens show a uniform ferroelectric grain without the presence of the pyrocholre phase. Average grain size increased with an increase in sintering temperature, the value for the x=0.65 specimen sintered at 125$0^{\circ}C$ was 14.4${\mu}{\textrm}{m}$. The dielectric constant and dielectric loss of the x=0.65 specimen sintered at 125$0^{\circ}C$ were 1247, 2.05%, respectively. All specimens showed fairly good temperature and frequency stability of dielectric constant with the range from -2$0^{\circ}C$ to 6$0^{\circ}C$ and 100Hz to 10MHz. The coercive electric field and the remanent polarization of x = 0.65 specimen sintered at 125$0^{\circ}C$ were 8.5 kV/cm and 13 $\mu$C/cm$^2$, respectively.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.11a
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• pp.188-191
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• 2000

The properties of piezoelectric and dielectric for 0.05Pb(Mn$\_$0.4/W$\_$0.2/Nb$\_$0.4/)O$_3$ - 0.95PbZr$\_$x/Ti$\_$1-x/O$_3$ compositions have been investigated. In the composition of 0.05Pb(Mn$\_$0.4/W$\_$0.2/Nb$\_$0.4/)O$_3$ - 0.95PbZr$\_$0.51/Ti$\_$0.49/O$_3$, the values of k$\_$p/ and $\varepsilon$$\_$33/$\^$T// $\varepsilon$$\_$0/ are maximized, but Q$\_$m/ was minimized (k$\_$p/=56.5[%], Q$\_$m/=1130, d$\_$33/=258[pC/N], $\varepsilon$$\_$33/$\^$T// $\varepsilon$$\_$0/=1170). The grain size was suppressed and the uniformity of grain was improved at the 1100[˚C]. Also, we can see the dielectric constants variations between the before poling and after poling. This effect results from the effect(increase element of dielectric constants) between dipole switching and electrostriction inducing stress and dipole direction to the poling orientation(decrease element of dielectric constants). At x=0.51, we can find MPB(morphotropic phase boundary).

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.05a
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• pp.509-512
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• 1999

Ferroelectric Sr$_2$(Nb, Ta)$_2$O$_{7}$(SNTO), La$_2$Ti$_2$O$_{7}$(LTO) thin films were prepared by sol-gel processes. SNTO, LTO thin films were spin-coated on Pt/TiO$_2$/SiO$_2$/Si(100). Pt/Ti/SiO$_2$/Si(100). PT/ZrO$_2$/SiO$_2$/Si(100) substrates. After multiple coating, dried thin films were heat-treated for decomposition of residual organics and crystallization. Dielectric and other relevant electrical properties were measured and the results showed a little possibility in ferroelectric gate random access memory devices.ces.

• Electrical & Electronic Materials
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• v.3 no.4
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• pp.279-286
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• 1990

고출력 변환기재료로 이용하기 위하여 유전손실에 기인한 압전 특성의 열화를 방지할 수 있는 큐리점이 비교적 높은 Pb$_{2}$FeNbO$_{6}$의 제3성분을 PZT에 고용한 고용체에서 양호한 압전특성을 갖는 조성을 찾고, 기계적 품질계수를 개선하고자 Cr$_{2}$O$_{3}$를 첨가한 변성 3성분계에 대하여 조사하였다. 그 결과, 전기기계결합계수가 가장 큰 조성은 0.05Pb(FeNb)O$_{3}$-0.4275PbTiO$_{3}$-0.5225 PbZrO$_{3}$이었으며 이조성의 기계적 품질계수, 상전이점은 170, 399.deg.C이었으며 이조성에 0.1wt% Cr$_{2}$O$_{3}$첨가한 변성 3성분계의 기계적 품질계수는 320으로 개선되었다.