• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.11a
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• pp.212-213
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• 2005

In this study, in order to develop low temperature sintering piezoelectric actuator, $Pb_{0.985}Bi_{0.01}(Mg_{1/2}W_{1/2})_{0.03}(Ni_{1/3}Nb_{2/3})_{0.13}(Zr_{0.50},Ti_{0.50})_{0.84}$ (PMW-PNN-PZT) ceramic systems were fabricated using $CaCO_3-Li_2CO_3$, sintering aid through a post-annealing process. The sinterability of PMW-PNN-PZT ceranics was remarkably enhanced by liquid phase sintering of $CaCO_3$ and $Li_2CO_3$. But, it was confimed form the X-ray diffraction pattern that the secondary phase along grain boundaries, deteriorated the piezoelectric properties. The secondary phase along grain boundaries was significantly removed by annealing after sintering. The 0.2wt% $Li_2CO_3$-0.25wt% $CaCO_3$-added PMW-PNN-PZT ceramics post-annealed at 900$^{\circ}C$ for 90min exhibited the excellent electromechanical coupling factor($k_p$) of 63.3% and piezoelectric constant($d_{33}$) of 452pC/N, respectively, for multilayer piezoelectricactuatorapplication.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.20 no.11
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• pp.953-958
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• 2007

In this paper, multilayer actuator structured-ultrasonic nozzle and resonant inverter driving circuit were manufactured, respectively. Its electrical properties were investigated. Multilayer actuator structured ultrasonic nozzle was fabricated using PMN-PNN-PZT ceramics showing excellent piezoelectric characteristics. In order to drive ultrasonic nozzle, resonant PWM inverter was used. The purpose of this study is to find the optimal driving condition of ultrasonic nozzle. Accordingly, electrical and temperature characteristic of multilayer ultrasonic driving system were investigated by experiments as a function of the series resonance inductance. The driving current of ultrasonic nozzle showed the maximum current of 27 mA. Also, the surface temperature of ceramic vibrator showed $44^{\circ}C$ at driving time for 20 min. The ultrasonic nozzle was stably operated in the case of driving for more than 20 min.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07b
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• pp.946-949
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• 2003

This paper reports on the fluid flow simulation results of a multilayer type piezoelectric valve. The mechanical and fluidic analysis are done by finite element method. The designed structure is normally closed type using buckling effect, which is consist of three separate structures; a valve seat die, an actuator die and a MLCA(Multilayer Type Ceramic Actuator). It is confirmed that the complete laminar flow and the lowest flow leakage are strongly depend on the valve seat geometry. In addition, turbulent flow was occurs in valve outlet according to increase seat dimension, height and inlet pressure. From this, we was deducts the optimum geometry of the valve seat and diaphragm deflection that have an great influence fluid flow in valve. Thus, it is expected that our simulation results would be apply for piezoelectric applications such as valve and pump, fluidic control systems.

• Transactions on Electrical and Electronic Materials
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• v.9 no.3
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• pp.91-95
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• 2008

In this study, in order to develop the composition ceramics for low loss multilayer piezoelectric actuator application, $Pb(Zn_{1/2}W_{1/2})O_3-Pb(Mn_{1/3}Nb_{2/3})O_3-Pb(Zr,Ti)O_3$ (abbreviated as PZW-PMN-PZT)ceramics according to the amount of $MnO_2$ addition were fabricated using two-stage calcinations method. And also, their dielectric and piezoelectric properties were investigated. At the 0.2 wt% $MnO_2$ added PZW-PMN-PZT ceramics sintered at $930^{\circ}C$, density, electromechanical coupling factor $k_p$, dielectric constant ${\varepsilon}_r$, piezoelectric $d_{33}$ constant and mechanical quality factor $Q_m$ showed the optimum value of $7.84g/cm^3$, 0.543, 1,392, 318.7 pC/N, 1,536, respectively for low loss multilayer ceramics actuator application.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.4
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• pp.1229-1232
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• 2010

In this study, in order to develop multilayer piezoelectric transformer for high electromechanical coupling factor and mechanical quality factor. and to show the general approach to the design of inverters utilizing PT as a circuit element. The description of the piezoelectric effect is not present here and can be easily found in numerous publications as well as complex equations and formulae. What is the most important to understand is that "they are different" -one cannot just change an electromagnetic transformer (EMT) for a piezoelectric one. Several examples of PT-based circuitry will help to start and use multilayer piezoelectric transformer advantages most effectively.

• Proceedings of the Korean Ceranic Society Conference
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• 2003.04a
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• pp.104.2-104
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• 2003

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.290-291
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• 2007

In this study, in order to develop low temperature sintering ceramics for multilayer piezoelectric actuator, sensers, transducers, PMN-PNN-PZT ceramics were manufacrtured with the sintering temperature, and their piezoelectric and dielectric properties were investigated. At the composition ceramics sintered at $900^{\circ}C$, desity, dielectric constant$({\varepsilon}_r)$, electromechanical coupling factor(kp), piezoelectric constant$(d_{33})$ and mechanical quality factor(Qm) showed the optimal value of $7.86g/cm^3$, 1417, 0.634, 410pC/N and 1138, respectively.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.11a
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• pp.32-33
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• 2006

In this study, in order to develop multilayer ceramic actuator for ultrasonic nozzle and ultrasonic vibrator, PMN-PNN-PZT ceramics were fabricated using $Li_2CO_3$. $Na_2CO_3$ and ZnO as sintering aids. And then, their piezoelectric and dielectric properties according to the amount of ZnO addition were investigated. The addition of ZnO improved density, dielectric constant, electromechanical coupling factor, mechanical quality factor and piezoelectric d constant of PMN-PNN-PZT ceramics due to the increase of sinterability and accepter doping effect. Electromechanical coupling factor and mechanical quality factor of PMN-PNN-PZT ceramics increased with ZnO amount up to 0.4wt% and then decreased. At the sintering temperature of $900^{\circ}C$ and 0.4wt% ZnO addition, density, dielectric constant, electromechanical coupling factor, mechanical quality factor and piezoelectric d constant showed the optimum value of 7.876g/$cm^2$, 1299, 0.612, 1151 and 369pC/N, respectively.

• Electrical & Electronic Materials
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• v.10 no.1
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• pp.20-25
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• 1997

In this study, piezoelectric actuator samples were fabricated using 0.375PMN-0.37OPT-0.255PZ system ceramics with Barium substitution and the strain properties of them were investigated. Dielectric constant of the specimens increased with the increase of Ba content up to 5mol% and decreased with futher addition of Ba. The largest piezoelectric coefficient and electromechanical coupling coefficient were observed at the sintering temperature of 1250'C and Barium content of 5mol%. The characteristics of strain hysteresis was found largely with varing the sintering temperature on the single round type, and the strain is proportional to piezoelectric coefficient.

• Proceedings of the Korean Magnestics Society Conference
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• 2003.12a
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• pp.145-145
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• 2003