• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.15 no.9
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• pp.794-797
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• 2002

Piezoelectric properties of PZT-PSN ceramics were investigated as a function of WO$_3$ addition from 0 wt% to 6.0 wt%. The dielectric and piezoelectric characteristics of PZT-PSN ceramics have been investigated at different calcination (80$0^{\circ}C$~90$0^{\circ}C$) and sintering (110$0^{\circ}C$~130$0^{\circ}C$) temperatures. The grain size was increased with the addition of WO$_3$and the sintering temperatures. Anisotropic properties of electromechanical coupling coefficient and piezoelectric coefficient are proven to be dependent on processing temperatures and amount of addition. At the specimen with 0.6 wt% WO$_3$ addition, using calcination temperature of 80$0^{\circ}C$ and sintering temperature of 110$0^{\circ}C$ , mechanical quality factor(Q$_{m}$) and electromechanical coupling coefficient(k$_{p}$) showed the excellent results of 1560 and 0.48, respectively Experimental results indicated that the PZT-PSN system ceramics with WO$_3$impurity could be effectively used for the microtransformer and actuator applications, etc.etc.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.19 no.9
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• pp.838-842
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• 2006

0.03Pb$(Sb_{0.5}Nb_{0.5})O_{3}-0.03Pb(Mn{1/3}Nb{2/3)O_{3}-(0.94-x)PbTiO_{3}-xPbZrO_{3}$ ceramics doped with $CeO_{2}$ were synthesized by conventional bulk ceramic processing technique. Phases analysis, microstructures and piezoelectric properties were investigated as a function of $CeO_{2}$ content (0.03, 0.05, 0.1 0.3, 0.5 and 0.7 wt%). Microstructures and phases information were characterized using a scanning electron microscope (SEM) and an X-ray diffractometer (XRD). Mechanical quality factor ($Q_{m}$) and coupling factor(kp) were obtained from the resonance measurement method. Both $Q_{m}$ and $k_{p}$ were shown to reach to the maximum at 0.1 wt% $CeO_{2}$. In order to evaluate the stability of resonance frequency and effective electromechanical coupling factor ($K_{eff}$) as a function of $CeO_{2}$, the variation of resonance and anti-resonance frequency were also measured using a high voltage frequency response analyzer under various alternating electric fields from 10 V/mm to 80 V/mm. It was shown that the stability of resonance frequency and effective electromechanical coupling factor were increased with increasing the $CeO_{2}$ contents.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.05c
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• pp.131-134
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• 2001

In this paper, the piezoelectric and dielectric properties as a function of x and a in $aPbZr_xTi_{1-x}O_3-(1-a)Pb(Mn_{1/3}Nb_{2/3})O_3$ + ywt%MgO is investigated. As a results, when a is 0.95 and x is 0.505, electromechanical coupling factor$(k_p)$, permittivity${\varepsilon}_33^T/{\varepsilon}_0$, piezoelectric strain constant$(d_{33})$ and mechanical quality factor$(Q_m)$ are 58 %, 1520, 272 pC/N and 1550, respectively. From XRD analysis, when x is 0.505, it is MPB which present rhombohedral and tetragonal phase in same quantity. Also, From SEM observation, when sintering temperature is $1150^{\circ}C$, grain size is about $2\;{\mu}m$. As a results added MgO dopant in the ternary piezoelectric ceramic, when MgO content is 0.1 wt%, $k_p$ increases to 63[%].

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.11 no.5
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• pp.394-399
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• 1998

High power characteristics with vibration velocity were studied in $Pb(Y_{2/3}W_{1/3})O_3-Pb(Zr,Ti)O_3$(PYW-PZT) ceramics by using the constant current method. Young s modulus $Y_0^E$ and mechanical quality factor $Q_m$ are a function of the square of effective vibration velocity \upsilon_0$. The nonlinear proportional constants of the above functions indicate the degree of stability under the vibration level change. The stability of PYW-PZT ceramics estimated by these constants coincides with the results obtained through the heat generation. It was found that $Q_m$ was markedly decreased with increasing the vibration velocity, accompanying a lot of heat generation. The vibration hysteresis and dielectric loss according to the vibration velocity was reduced by doping $Fe_2O_3$to the ceramics. On the contrary, these losses was increased by doping $Nb_2O_5$.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.13 no.3
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• pp.220-226
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• 2000

The piezoelectric material for piezoelectric transformer needs the high electromechanical coupling factor( $k_{p}$) the piezoelectric constant( $d_{33}$) and the mechanical quality factor( $Q_{m}$)in order to obtain high voltage step-up ratio and low temperature rising. In this study the piezoelectric transformers were fabricated using Pb［$Zr_{0.45}$/ $Ti_{0}$48//L $u_{0.02}$(M $n_{1}$3//S $b_{2}$3/)$_{0.05}$］ $O_3$(PMS-PZT) and Pb［Z $r_{0.25}$/ $Ti_{0.375}$(M $g_{1}$3//N $b_{2}$3/)$_{0.375}$］ $O_3$+0.5wt%Mn $O_2$(PMN-PZT) ceramics. The piezoelectric properties of PMS-PZT and PMN-PZT were measured. The voltage set-up ratios of the piezoelectric transformers using PMS-PZT and PMN-PZT were the value of 15, 20 respectively under 100$_{KΩ}$ in Rosen type transformer.r.ormer.r.r.r.r.r.r.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.172-173
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• 2008

In this study, $0.95(K_{0.5}Na_{0.5})NbO_3$-0.05Li$(Sb_{0.8}Nb_{0.2})O_3$ + $Ag_2O$ + x wt% $MnO_2$ were investigated as a function of the amount of $MnO_2$ addition in order to improve dielectric and piezoelectric properties of Lead-free piezoelectric ceramics. With increasing the amount of $MnO_2$ addition, density and electromechanical coupling factor $(k_p)$ increased up to 0.3wt.% $MnO_2$ and decreased above 0.3wt.% $MnO_2$. At the sintering temperature of 1020 $^{\circ}C$, Electromechanical coupling factor $(k_p)$, density, dielectric constant $({\varepsilon}r)$ and mechanical quality factor $(Q_m)$ of composition ceramics with 0.4wt% $Ag_2O$ addition showed the optimal value of 0.431, 4.33 g/$cm^3$, 820 and 119, respectively.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.21 no.2
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• pp.126-130
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• 2008

In this study, in order to develop low loss multilayer piezoelectric actuator, PZN-PZT ceramics were fabricated using $Li_2CO_3,\;Bi_2O_3$, CuO and ZnO as sintering aids, their structural, piezoelectric and dielectric characteristics were investigated according to the amount of ZnO addition, At the sintering temperature of $870^{\circ}C$, the density, electromechanical coupling factor(kp), mechanical quality factor(Qm), dielectric constant(${\epsilon}_r$) and piezoelectric constant($d_{33}$) of 0.4 wt% ZnO added specimen (sintered at $870^{\circ}C$) showed the optimum value of $7.812g/cm^3$, 0.535, 916, 1399, 335 pC/N respectively. Taking into consideration above piezoelectric properties of the specimen sintered at low temperature, it was concluded that PZN-PZT ceramics using 0.4 wt% ZnO as additive showed the optimum characteristics as the composition ceramics for low loss multilayer piezoelectric actuator application.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.19 no.8
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• pp.707-711
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• 2006

ZnO was doped up to 0.3 wt% for improving the electrical properties of lead-free $[Li_{0.04}(Na_{0.44}Ko_{0.52})-(Nb_{0.86}\;Ta_{0.10}\;Sb_{0.04})]O_3$ piezoelectric ceramics. The ceramics were fabricated with the conventional sintering processes. Crystal structure of the samples was tetragonal phase regardless of ZnO amount. However, the piezoelectric properties were varied with the ZnO amount. The electro-mechanical coupling factor $(k_p)$ was with the ZnO amount up to 0.2 wt% but decreased with the further addition. the maximum value of $k_p$ was 0.475. Density, piezoelectric charge constant and relative dielectric constant was also showed maximum value at 0.2 wt%. The maximum values are $4.75g/cm^3$, 275 pC/N, 1403, respectively. In contrast, the mechanical quality factor $(Q_m)$ was not varied with increasing the ZnO addition up to 0.2 wt% but rapidly increased at 0.3 wt%.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.23 no.5
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• pp.379-382
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• 2010

In this study, in order to develop the lead-free piezoelectric ceramics with high piezoelectric and dielectric properties, $(K_{0.5}Na_{0.5})(Nb_{0.97}Sb_{0.03})O_3$ ceramics were fabricated using a conventional mixed oxide process and their piezoelectric and dielectric characteristics were investigated according to the $K_{5.4}Cu_{1.3}Ta_{10}O_{29}$ addition. $K_{5.4}Cu_{1.3}Ta_{10}O_{29}$ addition enhanced density, electromechanical coupling factor($k_p$) piezoelectric constant $d_{33}$ and mechanical quality factor($Q_m$). At the 0.9 mol% $K_{5.4}Cu_{1.3}Ta_{10}O_{29}$ addition, density, electromechanical coupling factor($k_p$), dielectric constant(${\varepsilon}_r$) and piezoelectric constant($d_{33}$) of specimen showed the optimum values of 0.46, 471, and 148 pC/N, respectively.

• Transactions on Electrical and Electronic Materials
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• v.15 no.4
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• pp.226-229
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• 2014

In this study, lead-free $(Ba_{0.85}Ca_{0.15})(Ti_{1-x}Zr_x)O_3$ ceramics and a bimorph-type piezoelectric actuator were fabricated using the normal oxide-mixed sintering method, and their dielectric properties, microstructure, and displacement properties were investigated. From the results of X-ray diffraction, the pattern of the specimen has a pure perovskite structure. In addition, no secondary impurity phases were found. The excellent piezoelectric coefficient of $d_{33}=454pC/N$, the electromechanical coupling factor $k_p=0.51$, the dielectric constant ${\varepsilon}_r=3,657$, the mechanical quality factor $Q_m=239$, and $T_c$(Tetragonal-Cubic) =$90^{\circ}C$ were shown at x= 0.085. ${\Delta}k_p/k_p20^{\circ}C$ and ${\Delta}f_r/f_r20^{\circ}C$ showed the maximum value of -0.255 and 0.111 at $-20^{\circ}C$ and $80^{\circ}C$, respectively. The maximum total-displacement was $60{\mu}m$ under the input voltage of 50 V. As a result, it is considered that lead-free $(Ba_{0.85}Ca_{0.15})(Ti_{1-x}Zr_x)O_3$ ceramics is a promising candidate for piezoelectric actuator application for x= 0.085.