• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 하계학술대회 논문집 Vol.6
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• pp.346-347
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• 2005

In this study, in order to develop the low temperature sintering ceramics, PZT ceramics adding $MnO_2$, $B_2O_3$ were manufactured, and their piezoelectric and dielectric properties is investigated. The results of this study were gotten such as follows. The electromechanical coupling coefficient(kp) showed good properties on the whole, showed its maximum value 28.266 in specimens sintered at 1200[$^{\circ}C$]. The mechanical quality coefficient(Qm) showed its maximum value 162.61 in specimens sintered at 1200[$^{\circ}C$] and was increased by increasing sintering temperature. The dielectric constant showed the optimum values of 538.903 at specimen sintered at $1000^{\circ}C$.

• 한국전기전자재료학회논문지
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• 제13권3호
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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.

• 한국전기전자재료학회논문지
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• 제35권5호
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• pp.445-451
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• 2022

Ultrasonic sensor is suitable as a next-generation autonomous driving assist device because its lower price compared to that of other sensors and its sensing stability in the external environment. Although Pb(Zr, Ti)O₃ (PZT)-relaxor ferroelectric system has excellent piezoelectric properties, the change in capacitance is large in the daily operating temperature range due to the low phase transition temperature. Recently, many studies have been conducted to improve the temperature stability of ferroelectric ceramics by controlling the grain size and crystal structure, so it is necessary to study the effect of the grain size on the piezoelectric properties and the temperature stability of PZT-relaxor ferroelectric system. In this study, the piezoelectric properties, phase transition temperature, and temperature coefficient of capacitance (TCC) of 0.9 Pb(Zr_1-xTi_x)O₃-0.1 Pb(Zn_1/3Nb_2/3)O₃ (PZT_x-PZN) ceramics with various grain sizes were investigated. PZT_x-PZN ceramics with larger grain size showed higher piezoelectric properties and temperature stability, and are expected to be suitable for ultrasonic devices in the future.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1993년도 춘계학술대회 논문집
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• pp.109-112
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• 1993

In this paper, We have studied about the microstructure of the piezoceramics PZT that were added with some kinds of additives, such as Niobium(Nb), Iron(Fe) or Manganese(Mn). The grain size of PZT ceramics was decreased with increasing the amounts of additive of Nb or Fe, while increased with increasing Mn. The curie temperature was changed slightly for the PZT ceramics containing $Fe^{3+}$, which is not dependent on the amounts, but $Nb^{5+}$ or $Mn^{2+}$ ion added PZT was lowered. The resistivity was increased with increasing the amounts of $Nb^{5+}$ additive, while decreased for $Mn^{2+}$ additive.

• The Korean Journal of Ceramics
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• 제4권4호
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• pp.352-355
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• 1998

Dense $ Pb(Zr, Ti)O_3(PZT)/Al_2O_3$ nanocomposites were prepared by the 28 GHz microwave heating method and conventional electric furnace sintering. Electrical and mechanical properties of the composites were investigated. The fracture strength of the PZT composites with 0.1vol% $Al_2O_3$ was significantly improved in both sintering methods. Smaller grain size and effective reinforcement of the PZT matrix by the second phase were considered to be responsible for the excellent fracture strength. Planar electromechanical coupling factor Kp of the composites sintered by 28GHz microwave heating was higher than that of the materical prepared by the conventional route. It seemed that the control of the reaction between PZT and $Al_2O_3$ by the microwave rapid sintering resulted in the high piezoelectric properties.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1995년도 춘계학술대회 논문집
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• pp.17-21
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• 1995

Tw types of Pb(Mn$\sub$1/3/Nb$\sub$2/3/)O$_3$+PZT Ceramics had been fabricated by hot-pressing method. One had cause grain and the other had fine grain doe to Cr$_2$O$_3$ addition. These specimen were poled by applying the DC electric field in various steps. The effects of thermal aging on their piezoelectric characteristics and temperature stability of the frequency were investigated.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1992년도 하계학술대회 논문집 B
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• pp.727-729
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• 1992

In this study, the piezoelectric composites with 1-3 connectivity have been studied. A piezoelectric ceramics PZT prepared by Flux method is used as a filler in a epoxy Eccogel polymer matrix. The piezoelectric coefficients were increased as PZT volume% increases, and resonance frequency was moved to lower frequency as the sample thickness increased. The acoustic matching impedance with water is lowered than single phase PZT ceramics.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 추계학술대회 논문집 Vol.14 No.1
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• pp.30-33
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• 2001

This thesis deal with ferroelectric and ferrimagnetic materials, PZT/Ferrite ceramics. We conducted test of magnetical and electrical measurement. From this measurement, We obtained tunability and we can control characteristic impedance($Z_0$) from permeability($\mu$) and dielectric constant($\varepsilon$) for impedance matching in transmission line.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 추계학술대회 논문집
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• pp.30-33
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• 2001

This thesis deal with ferroelectric and ferrimagnetic materials, PZT/Ferrite ceramics. We conducted test of magnetical and electrical measurement. From this measurement, We obtained tunability and we can control characteristic impedance(Z$_{0}$) from permeability($\mu$) and dielectric constant($\varepsilon$) for impedance matching in transmission line.e.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 하계학술대회 논문집
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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.