• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.11a
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• pp.219-220
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• 2006

In this study, m order to develop multilayer ceramics vibrator for ultrasonic nozzle, PMN-PNN-PZT ceramics were fabricated using $Li_2CO_3-Na_2CO_3$ as sintering aids and their piezoelectric and dielectric characteristics were investigated according to the aomunt of PbO. With increasing PbO contents. secondary phases were increased and phase structure were changed from tetragonal structure to rhombohedral structure and also electromechanical coupling factor were linearly decreased. At the composition ceramics with the sintering temperature of $870^{\circ}C$ and 1 mol% excess PbO, density, electromechanical coupling factor, dielectric constant, piezoelectric d constant and mechanical quality factor showed the optimum value of $7.879g/cm^2$, 0.55, 1149, 328pC/N, 1224, respectively for multilayer ceramics vibrator application for ultrasonic nozzle.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.11a
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• pp.217-218
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• 2006

In this study, In order to develop the low temperature sintering multilayer piezoelectric actuator, PMN-PNN-PZT system ceramics were manufactured with the sintering temperature, and their microstructure and piezoelectric properties were investigated. At the composition ceramics sintered at $900^{\circ}C$, dielectric constant(${\varepsilone}_r$), electromechanical coupling factor($k_p$), piezoelectric constant($d_{33}$) and mechanical quality factor(Qm) showed the optimal value of 1095, 0.60, 363 and 1055, respectively, for multilayer piezoelectric actuator application.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.19 no.12
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• pp.1118-1122
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• 2006

In this study, in order to develop the low temperature sintering multilayer piezoelectric actuator, PMN-PNN-PZT system ceramics were manufactured and their microstructure, ferroelectric and piezoelectric properties were investigated. By increasing sintering temperature, remanent polarization$(P_r)$ was increased due to the increase of sinterability and grain size. However, coercive $field(E_c)$ showed an opposite tendency to remanent polarization owing to the feasibility of domain wall motion. At the sintering temperature of $900^{\circ}C$, dielectric $constant({\varepsilon}_r)$, electromechanical coupling $factor(k_p)$, piezoelectric $constant(d_{33})$ and mechanical quality $factor(Q_m)$ showed the optimal value of 1095, 0.60, 363 and 1055, respectively, for multilayer piezoelectric actuator application.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.15 no.7
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• pp.597-601
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• 2002

In this study, the structural, dielectric and piezoelectric properties of $Pb[(Ni_{1/3}Nb_{2/3})_x-(Mn_{1/3}Nb_{2/3})_{0.09-x}-(Zn_{0.505}Ti_{0.495)_0.91]O_3$ (x=0, 0.01, 0.02, 0.03, 0.04, 0.05) system ceramics were investigated to develop the composition ceramics for piezoelectric transformer. All the specimens were sintered at $1250^{\circ}C$ and its physical properties were measured, and the results are as follows : With increasing PNN substitution for PMN-PZT system, dielectric constant was increased and electro-mechanical coupling factor($k_p$) was increased to 0.62 at 5 mol% while mechanical quality factor(Qm) was decreased.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.203-204
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• 2008

In this study, in order to develop the multilayer piezoelectric actuator and ultrasonic resonator, PMN-PNN-PZT ceramics were fabricated by the variations of ball size at sintering temperature of $900^{\circ}C$ and their piezoelectric and dielectric characteristics were investigated as a function of the variations of ball size. When the ball size was 3mm$\phi$, density, dielectric constant$({\varepsilon}r)$, electromechanical coupling factor(kp) and piezoelectric d constant$(d_{33})$ were increased. At the ball size of 3mm$\phi$, the specimen showed the optimum values of density=7.909g/$cm^3$, kp=0.592, Qm=1292, $d_{33}$=368pC/N, $\varepsioln_r$=1502, respectively.

• Journal of the Korean Ceramic Society
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• v.42 no.10 s.281
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• pp.685-690
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• 2005

Pb(Zr,Ti)$O_{3}$Pb($Mn_{1/3}$$Nb_{2/3}$)$O_{3}$ powder was successfully synthesised by high-energy milling method, and the behavior of low­temperature sintering and piezoelectrical properties of Pb(Zr,Ti)$O_{3}$-Pb($Mn_{1/3}$$Nb_{2/3}$)$O_{3}$ ceramics were investigated as a function of mechanical alloying time. In order to confirm whether the Perovskite phase in this composition was formed by mechanical activation technique or not, we performed X-Ray Diffraction pattern analysis (XRD). The microstructure for the sintered samples were characterized using a Scanning Electronic Microscope (SEM). And the piezoelectrical properties ($k_{p}$ and $Q_{m}$) of the sintered samples was measured using HP 4194A impedance analyzer.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.04b
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• pp.161-164
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• 2004

In this study, to develop the composition ceramics for the Ultrasonic vibrator, $Pb(Mn_{1/3}Nb_{2/3})O_3Pb(Zr.Ti)O_3$ system ceramics were manufactured as a function of PCN substitution. Its dielectric and piezoelectric characteristics were investigated. With increasing the amount of PCN substitution, electromechanical coupling factor(kp) were increased until 3mol% PCN and that after decreased. mechanical quality factor(Qm) showed the maxinum value at 2mol% PCN. Eletromechanical coupling factor, mechanical quality factor and dielectric constant were showed optimum value at PCN 2mol% as 0.58, 1630 and 1407, respectively for ultrasonic vibrator applications.

• Transactions on Electrical and Electronic Materials
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• v.6 no.1
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• pp.6-9
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• 2005

Aging characteristics of 0.2PMN-0.8PZT multilayer ceramic actuators (MCA) has been investigated by applying both triangular wave function for unpoled and unipolar wave for poling. P-E hysteresis loops of the MCA had been distorted after about 90 million cycles running in triangular wave function. Effective electromechanical coupling coefficient was calculated in resonant and anti resonant frequencies. And pseudo-piezoelectric constant $d_{33}$ was also estimated from the strain versus electric field characteristics. The crack growth of MCA was clearly observed along to the boundary between electrode and inactive area. That results were thought due to the internal tensile stress came from both actuation of $d_{33}$ mode and motion of Poisson ratio.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.11b
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• pp.438-441
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• 2001

In this study,microstructure and piezoelectric characteristics of PNW-PMN-PZT ceramics manufactured using attrition milling method were investigated. Sintering temperature of the ceramics was varied from $1180^{\circ}C$ to $1240^{\circ}C$.With increasing sintering temperature, dielectric constant was increased. In the specimen sintered at $1120^{\circ}C$,electromechanical coupling factor(Kp) and density showed the maxinum values of 0.546 and $7.78(g/cm^{3})$, respectively. In the specimen sintered at $1160^{\circ}C$,mechanical quality factor(Qm) also showed the maxinum value of 1,943.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.11a
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• pp.280-283
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• 2002

In this study, the effects of $Nb_{2}O_{5}$ addition on microstructure and piezoelectric characteristics of PNW-PMN-PZT ceramics were investigated. As $Nb_{2}O_{5}$ addition amount is increased, grain size is gradully decreased. At 0.3wt%$Nb_{2}O_{5}$ addition composition ceramics, maximum density, tetragonality and piezoelectric characteristics were obtained.