• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2009.05a
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• pp.436-438
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• 2009

In this study, in order to develop the composition of ceramics capable of being sintered at low temperature with high piezoelectric properties, PZW-PMN-PZT system ceramics for piezoelectric energy harvesting application were manufactured according to the amount of PZW addition. And also, their microstructural, dielectric and piezoelectric properties were investigated. At the sintering temperature of $930^{\circ}C$, a 5 mol% PZW substituted specimen showed a maximum value of density = $7.905g/cm^3$, kp = 0.585, $d_{33}$ = 351pC/N and Qm =1,254, respectively.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07a
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• pp.117-120
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• 2004

The dielectric and piezoelectric properties of silver doped $Pb(Zr,Ti)O_3-Pb(Mn,W,Sb,Nb)O_3$ ceramics was examined. By varying the contents of silver(0.0, 0.4, 1.0 mol%), the effect of doped silver on PZT-PMWSN thin film was investigated at various sintering temperature(900, 1000, $1100^{\circ}C$). As increasing silver contents, the relative dielectric constant is increased and sinterbility is enhanced. At the specimen with 0.4 mol% Ag and sintered at $1100^{\circ}C$, electromechanical coupling factor(kp), mechanical quality factor(Qm), dielectric constant(${\varepsilon}r$) and dielectric loss were 0.502, 811, 991, 0.006, respectively. The results show that the PZT-PMWSN/Ag composites have enhanced piezoelectic and dielectric properties and processing condition is improved.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.19 no.5
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• pp.417-421
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• 2006

In this study, in order to develop low temperature sintering piezoelectric ceramics for LTCC (Low-Temperature Cofired Ceramic) multilayer piezoelectric actuator, PMW-PMN-PZT ceramics using $0.2wt%\; Li_2CO_3$ and $0.25wt%\;CaCO_3$ as sintering aids were investigated according to the varation of PMW substution. Composition ceramics could be sintered at $900^{\circ}C$ by adding sintering aids. As the amount of PMW substitution increased, the crystal structure of PMW-PMN-PZT ceramics moved from tetragonal phase to rhombohedral phase gradually, and MPB(Morphotrophic Phase Boundary) region appeared at 2 mol% PMW substitution. At the sintering temperature of $900^{\circ}C$, the density, electromechanical coupling factor(kp), mechanical quality factor(Qm), dielectric constant(${\epsilon}r$), piezoelectric constant(d33) and Curie temperature(Tc) of 2 mol% PMW substituted PMW-PMN-PZT ceramics showed the optimal values of $7.88g/cm^3$, 0.58, 1002, 1264, 352 pC/N and $336^{\circ}C$, respectively, for LTCC multilayer piezoelectric actuator application.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.25 no.8
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• pp.611-615
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• 2012

In this study non-stoichiometric $(K_{0.5}Na_{0.5})_{0.97}(Nb_{0.96-x}Ta_xSb_{0.04})O_3$ ceramics were prepared by the conventional soild-state teaction method. The effect of Ta-substitution on the dielectric and piezoelectric properties were investigated. X-ray diffraction analysis of all the specimens less than x= 15 mol% indicated orthorhombic phase. Thereafter, the specimens showed orthorhombic phase near to pseudo-cubic. Sinterablity of all the specimens was improved due to secondary products such as KCT and KCN. The ceramics with x= 5 mol% showed the optimum velues of pizoelectric constant($d_{33}$)= 150 pC/N, electromechanical coupling factor (kp)= 0.45, electromechanical quality factor (Qm)= 418.9 and dielectric constant(${\varepsilon}_r$)= 567. Accordingly, These results indicate that the composition ceramics is a promising candidate for lead-free material.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.222-223
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• 2008

Recently, piezoelectric transformer is applied to wide fields. Multi layer piezoelectric transformer has the advantage of high step up ratio, high electromechanical coupling coefficient(Kp) and high mechanical quality factor(Qm), however it shows the peeling-phenomenon of electrode, and high price due to high sintering temperature. Therefore this study focus on the method for fabrication of high power rosen type piezoelectric transformers. The composition of $0.01Pb(Ni_{1/3}Nb_{2/3)O_3$ - 0.08Pb$(Mn_{1/3}Nb_{2/3})O_3$-0.91Pb$(Zr_{0.505}Ti_{0.495})O_3$(abbreviated as PNN-PMN-PZT) ceramics is employed for this study.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.16 no.1
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• pp.33-38
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• 2003

Highly homogeneous PZT powder was prepared by a partial oxalate method using chemicals of (Z $r_{0.53}$ $Ti_{0.47}$) $O_2$, Pb(N $o_3$)$_2$and (COOH)$_2$ㆍ2$H_2O$. N $b_2$ $O_{5}$ addition effect on microstructure and electrical properties of PZT ceramics was investigated. When the precursors were calcined at 71$0^{\circ}C$, a single perovskite phase was obtained. After sintering at 110$0^{\circ}C$, X-ray diffraction Patterns showed coexistence of rhombohedral and tetragonal phases regardless of the N $b_2$ $O_{5}$ content. As the content of N $b_2$ $O_{5}$ increased, grain size decreased but sintered density increased. The electromechanical coupling factor of kp and the piezoelectric constant of $d_{31}$ increased linearly with the content of N $b_2$ $O_{5}$, and those values reached 0.7 and -200, respectively, when 1.2 mol% of N $b_2$ $O_{5}$ is added. is added.ded.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.26 no.11
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• pp.806-809
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• 2013

In this study, $(Na_{0.525}K_{0.443}Li_{0.037})(Nb_{0.883}Sb_{0.08}Ta_{0.037})O_3+0.10\;wt%Bi_2O_3+0.35\;wt%B_2O_3$ ceramics were prepared by conventional soild-state sintering process. The specimens were sintered at temperature range from $1,060^{\circ}C$ to $1,100^{\circ}C$. XRD (X-ray diffractron), SEM (scanning electron microscope) were used to analyze the crystal structure and microstructural sproperties of specimens. And also, $T_{O-T}$, TC were observed by the mesurement of temperature dependence of dielectric constant. Excellect physical properties of the piezoelectric constant $d_{33}$= 170 pC/N, electromechanical coupling factor kp= 0.312, Tc= $315^{\circ}C$ were obtained, respectively, from the specimen sintered at $1,080^{\circ}C$.

• Journal of Sensor Science and Technology
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• v.23 no.2
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• pp.105-109
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• 2014

Structure and electrical properties of $0.85NaNbO_3-0.15LiNbO_3$ ($(Li_{0.15}Na_{0.85})NbO_3$) ceramics were investigated as a function of sintering temperature. $(Li_{0.15}Na_{0.85})NbO_3$ ceramics were prepared by conventional solid state processing. A main phase of the orthorhombic perovskite structure and secondary phase of $LiNbO_3$ were confirmed for all sintered specimens. Dense $(Li_{0.15}Na_{0.85})NbO_3$ ceramics were obtained at sintering temperature above $1050^{\circ}C$. With increasing sintering temperature, the electromechanical coupling factor ($k_p$), piezoelectric constant ($d_{33}$) and relative dielectric constant (${\varepsilon}_r$) of the sintered specimens increased, while the mechanical quality factor ($Q_m$) decreased. These results are due to the increase of grain size and crystallite size of orthorhombic perovskite structure. Based on the temperature dependence of ${\varepsilon}_r$, stable piezoelectric properties were expected because no phase transition found up to $300^{\circ}C$. Typically, kp of 18%, $d_{33}$ of 34.7 pC/N, ${\varepsilon}_r$ of 135, and $Q_m$ of 62.8 were obtained for the specimens sintered at $1200^{\circ}C$ for 5 h.

• Journal of Sensor Science and Technology
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• v.6 no.5
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• pp.392-399
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• 1997

In this study, the effect of the sintering temperature on the dielectric and piezoelectric properties of 0.5 wt% $MnO_{2}$-doped $0.125Pb(Mg_{1/2}Nb_{2/3})O_{3}-0.435PbTiO_{3}-0.44PbZrO_{3}$ ceramics were investigated aiming at ultrasonic motor applications. From experimental result, it was found that the optimal sintering temperature condition was at $1270^{\circ}C$. The sample sintered at $1270^{\circ}C$ had density of $7.72\;g/cm^{3}$, dielectric constant of 570, dielectric loss of 0.82%, remanent polarization of $19.18{\mu}C/cm^{2}$, coercive field of 9.63 kV/cm, electromechanical coupling factor of radial mode of 55.1%, mechanical quality factor of 886. Temperature and frequency dependence of dielectric constant and dielectric loss of the sintered sample at $1270^{\circ}C$ was also investigated.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.1244-1245
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• 2008

Recently, piezoelectric transformer is applied to wide fields. Multi layer piezoelectric transformer has the advantage of high step up ratio, electromechanical coupling coefficient(Kp) and mechanical quality factor(Qm), but is indicated of peeling-phenomenon of electrode, rising sintering temperature made price of costly electrode. So in this study, it discuss on method for fabrication of rosen type piezoelectric transformers. For the fabrication as rosen type piezoelectric transformers, synthesized the powder using 0.01Pb$(ni_{1/3}Nb_{2/3})O_3$ - 0.08Pb$(Mn_{1/3}Nb_{2/3})O_3$ - 0.91Pb$(Zr_{0506}Ti_{0496})O_3$ (abbreviated as PNN-PMN-PZT) ceramics. The density, microstructure, dielectric and piezoelectric properties as a function of sintering temperature were investigated. The results indicated that the optimized properties of ceramics were obtained at sintering temperature of 1200$^{\circ}C$, showed the value of $d_{33}$=273pC/N, $K_p$=0.60 $Q_m$=1585, ${\varepsilon}_r$=1454, density=7.917$g/cm^3$ and $tan{\delta}$=0.0064.