• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.23 no.8
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• pp.617-621
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• 2010

($K_{0.5}Na_{0.5}$)($Nb_{0.96}Sb_{0.04}$)$O_3$+1.2 mol% $K_4CuNb_8O_{23}$ ceramics doped with iron oxide ($Fe_2O_3$) were prepared by a conventional mixed oxide method. And then, their piezoelectric and dielectric properties were investigated as a function of $Fe_2O_3$ addition. X-ray diffraction studies reveal that $Fe^{3+}$ diffuses into the NKN lattices to form a solid solution with a pure perovskite structure at room temperature. At the sintering temperature of $1,060^{\circ}C$, when 0.2 mol% $Fe_2O_3$ was doped, the piezoelectric constant ($d_{33}$), electromechanical coupling factor (Kp), and mechanical quality factor ($Q_m$) showed the excellent values of 131.67 pC/N, 0.436, and 696.36, respectively. Results show that $Fe_2O_3$ deped ($K_{0.5}Na_{0.5}$)($Nb_{0.96}Sb_{0.04}$)$O_3$+1.2 mol% $K_4CuNb_8O_{23}$ lead-free piezoelectric ceramics are a promising lead free material for piezoelectric transformer applications.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.44 no.11
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• pp.1488-1493
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• 1995

In this study, the structural, electrical and dielectric properties were investigated in (P $b_{0.76}$ $Ca_{0.24}$)[( $Co_{1}$2/ $W_{1}$2/)$_{0.04}$ $Ti_{0.96}$) $O_{3}$ system ceramics which were manufactured with the addition of Mn $O_{2}$. According to the increment of Mn $O_{2}$ addition, tetragonality was decreased. The specimen added with 1.5 mol% Mn $O_{2}$ and sintered at 1150.deg. C showed the highest density of 7.06[g/c $m^{3}$]. The variations of grain xize as a function of Mn $O_{2}$ addition were negligibly small. But grain was grown until 7.88[.mu.m] with increasing sintering temperature. Electromechamical coupling factor planar mode $K_{p}$ was decreased to a small value of $K_{p}$ = 0 in all the specimens added with Mn $O_{2}$ and sintered at 1150.deg. C & 1200.deg. C.& 1200.deg. C.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.19 no.10
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• pp.935-941
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• 2006

In this paper, the dielectric and piezoelectric properties of $0.4Pb(Ni_{1/3}Nb_{2/3})O_3+0.6Pb(Zr_{405}Ti_{595})O_3+X\;wt%\;Fe_2O_3$ ceramics were investigated with the addition of $Fe_2O_3$ and sintering temperature. Dielectric constant and piezoelectric constant increased with amount of $Fe_2O_3$ to 0.25 wt% and then decreased the further addition of $Fe_2O_3$. It seems that $Fe_2O_3$ acts as a sintering aid at the sintering temperature of $1150^{\circ}C$. By the addition of $Fe_2O_3$., sintering temperature of the system was lowered from $1250^{\circ}C\;to\;1100^{\circ}C$. The piezoelectric properties showed the maximum value of ${\varepsilon}r=4669,\;d_{33}=810(10^{-12}m/V)$, kp = 77 %, Qm = 55, in $0.4Pb(Ni_{1/3}Nb_{2/3})O_3\;-0.6Pb(Zr_{0.405}Ti_{0.595})O_3+0.25wt%\;Fe_2O_3$ ceramics having composition near the morphotropic phase boundary. The composition may be appropriate for actuator materials because of high piezoelectric constant and electromechanical coupling factor.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1305_1306
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• 2009

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.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.302-302
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• 2010

The lead-free piezoelectric ceramics must have high piezoelectric properties and electrical properties for the applications of piezoelectric devices. Therefore, KNN ceramics were investigated as a function of the variation of Nb. The density was increased with the increase of Nb. The density was saturated above 0.8895 mol Nb. The maximum value of electromechanical coupling coefficient(kp) was obtained 0.428 at 0.8895mol Nb. This result can be attributed to the well sintered of specimens. Also, The maximum value of mechanical quality factor(Qm) showed 1554 at 0.8895mol Nb. Therefore, this composition can be used for application of piezoelectric device such as piezoelectric transformer and piezoelectric actuator.

• Journal of the Korean Ceramic Society
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• v.30 no.1
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• pp.1-6
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• 1993

Dielectric and piezoelectric porperties of pseudoternary xPb(Al2/3W1/3)O3-(1-x)Pb(Zr0.52Ti0.48)O3 (x=1~10mol%) ceramic system have been investigated as a function of the amount of PAW[Pb(Al2/3W1/3)O3] and sintered from 110$0^{\circ}C$ to 120$0^{\circ}C$ for 1hr. As the amount of PAW increases, the c/a of tetragonal structure decreases. The grain size was reduced with increasing the amount of PAW addition. However, the density, dielectric constant and electromechanical coupling factor(kp) exhibited a maximum value at the amount of 5mol% PAW addition.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.11a
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• pp.178-180
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• 2005

In this study, in order to develop multilayer low temperature sintering piezoelectric transformer, $Pb_{0.97}Sr_{0.03}[(Mn_{1/3}Nb_{2/3})x(Zr_{0.48}Ti_{0.52})_{1-x}O_3]+$ 0.25wt% $CeO_2$+0.3 wt% $Nb_2O_5$ system ceramics were fabricated using $Li_2CO_3-CaCO_3$ and CuO as sintering aids and their piezoelectric and dielectric characteristics were investigated with the amount of PMN substitution. With increasing PMN substitution, electromechanical coupling factor kp and dielectric constant were increased.

• Journal of the Korean Ceramic Society
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• v.25 no.1
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• pp.7-14
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• 1988

In this paper, piezoelectric composite materials of 1-3 connectivity were prepared by using "dicing-filling" technique with PZT ceramics and epoxy polymers, and the dependence of piezoelectric properties on the thickness of specimens was investigated. In case that the PZT volume percent is 18.1%, according to an increment of thickness, the dielectric constant of composites( 33) is unchangeable, which is about 200, the piezoelectric coefficient (d33) is somewhat increased, which is about 240-280 (PC/N) and the electromechanical coupling factor of thickness mode(kt) is proportioned, but radial mode(kp) is constant.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.03a
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• pp.6-6
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• 2010

In this study, microstructural and piezoelectric characteristics of PNW-PMN-PZT ceramics manufactured using attrition milling method were investigated. Sintering temperature of the ceramics was varied from $980^{\circ}C$ to $1100^{\circ}C$. At the specimen sintered at $1100^{\circ}C$, mechanical quality factor(Qm) and dielectric constant showed the maxinum values of 2,373 and 1438, respectively. At the specimen sintered at $1080^{\circ}C$, electromechanical coupling factot(kp) also showed the maxinum value of 0.524.

• Proceedings of the KIEE Conference
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• 1985.07a
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• pp.191-193
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• 1985

Reaction temperature md piezoelectric properties of Pb(Mn1/3 Sb2/3)0.08 Ti0.495 Zr0.425 $O_3$ ceramics by hydrothermal synthesis method have been investigated. Sintering density and dielectric constant of sample increased with increasing of hydrothermal reaction temperature, while decreased rapidly above $240^{\circ}C$. Electromechanical coupling factor kp was almost constant at the reaction temperature $160^{\circ}-240^{\circ}C$.