• 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 $1000^{\circ}C$.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 하계학술대회 논문집 Vol.7
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• pp.325-326
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• 2006

In this study, in order to develop piezoelectric device for multilayer piezoelectric ultrasonic motor, low temperature sintering $Pb(Mn_{1/3}Nb_{2/3})_{0.02}(Ni_{1/3}Nb_{2/3})_{0.12}(Zr_{0.48}Ti_{0.52})_{0.86}O_3$ system ceramics were fabricated according to the variations of forming pressure of casting sheet. At the 300[$kgf/cm^2$] forming pressure, the maximum density of 7.8[$g/cm^3$] was obtained. At the 350[$kgf/cm^2$] forming pressure, the maximum values of effective electromechanical coupling factor $k_{cff}\;=\;0.24$ and mechanical quality factor Qm=628 were obtained.

• 한국전기전자재료학회논문지
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• 제14권5호
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• pp.356-361
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• 2001

The structureal, dielectric and piezoelectric properties of Pb[(Sb$\_$1/2/Nb$\_$1/2/)$\_$x/-(Ni$\_$1/3/Nb$\_$2/3/)$\_$0.15-x/-(Zr$\_$y/Ti$\_$1-y/)$\_$0.85/]O$_3$(x=0∼0.05, y=0.47∼0.52) ceramics were investigated with the substitution of Pb(Sb$\_$1/2/Nb$\_$1/2/)O$_3$(abbreviated PSN) and the Zr/Ti ratio. At Zr/Ti ratio of 50/50, tetragonality was decreased and grain size abruptly decreased with the increase of PSN substitution. Curie temperature was decreased and dielectric constant increased with the substitution of PSN. The coercive field increased and remnant polarization decreased with the substitution of PSN. Electromechanical coupling factor(k$\_$p/) showed the highest value of 0.622 at 1mol% PSN, but mechanical quality factor(Q$\_$m/) showed the minimum value at that composition. Dielectric constant and electromechanical coupling factor with the Zr/Ti ratio showed maximum values at Zr/Ti ratio of 50/50 and mechanical quality factor showed minimum values near the Zr/Ti ratio of 50/50.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1996년도 춘계학술대회 논문집
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• pp.63-67
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• 1996

In this paper, effect of MnO$_2$ addition(0, 0.1, 0.2, 0.3, 0.5wt%) on the microstructure, dielectric and piezoelectric properties of [xPMW - (0.15-x) PNN] - [yPT-(0.85-y)PZ] (x=0, 0.01, 0.02, 0.03, 0.05, y = 0.35, 0.40, ().425, 0.45, 0.5) were investigated. When Ti/Zr ratio was 1.0, dielectric and piezoelectric properties were highest value. With PMW 2mol%, dielectric constant, dielectric constant (d$\_$33/, d$\_$31/) and electromechanical coupling factor (kp, k$\_$31/) were highest values of 1995, 479, 186(x10$\^$-12/C/N), 0.61, 0.36, respectively. With the addition of MnO$_2$, dielectric constant, electromechanical coupling factor (kp, k$\_$31/) were decreased, but with 0.3wt% MnO$_2$, eletromechanical coupling factor was highest value of 0.63. With the addition of MnO$_2$, mechanical quality(Q$\_$m/ was increased.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 추계학술대회 논문집
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• pp.277-278
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• 2007

In this study, in order to develop multilayer piezo-actuator, PMN-PNN-PZT ceramics were fabricated using $Li_2CO_3,\;Na_2CO_3$, ZnO as sintering aids and their piezoelectric and dielectric properties were investigated according to the Bi substitution. Bi substitution enhanced electromechanical coupling factor$(k_p)$ and dielectric constant$({\varepsilon}_r)$. However, mechanical quality factor was deteriorated. At the sintering temperature of $870^{\circ}C$ and Bi substitution of 1mol%, density, electromechanical coupling factor$(k_p)$, mechanical quality factor$(Q_m)$, Dielectric constant$({\varepsilon}_r)$ and piezoelectric constant$(d_{33})$ of specimen showed the optimum value of $7.878g/cm^3$, 0.608, 835, 1603 and 397pC/N, respectively.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1999년도 추계학술대회 논문집
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• pp.269-272
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• 1999

In this study, electrical properties and TCFr of Pb(Sb$_{1}$2/Nb$_{1}$2/)O$_3$-Pb(Mn $_{1}$3/Nb$_{2}$3/)O$_3$-Pb(zr, Ti)O$_3$ composition ceramics were investigated wish the Zr/Ti ratio and the additions of Y2O3. and Fe$_2$O$_3$ Electromechanical coupling factor(Kp) showed the highest value of 0.555 in the Zr/Ti=0.50/0.50 ratio ,however, dielectric constant showed the highest value of 1,217 in the Zr/Ti = 0.49/0.51 ratio. Excellent TCFr vague of 421ppm/$^{\circ}C$] at-30~9O$^{\circ}C$ was appeared in the Zr/Ti=0.50/0.50 ratio and electro-mechanical coupling factor(Kp) , mechanical quility factor(Qm) and dielectric constant was 0.496, 1,286 and 1,085 ,respectively ,in the composition ceramics of lwt%Y$_2$O$_3$ and 0.3wt%Fe$_2$O$_3$.

• 한국전기전자재료학회논문지
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• 제22권11호
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• pp.925-929
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• 2009

In this study, $0.95(K_{0.5}Na_{0.5})NbO_3-0.05Li(Sb_{0.8}Nb_{0.2})O_3$ ceramics were investigated as a function of the amount of $Ag_2O$ addition in order to improve dielectric and piezoelectric properties of lead-free piezoelectric ceramics. With increasing the amount of $Ag_2O$ addition, density and electromechanical coupling factor ($k_p$) increased up to 0.2 wt.% $Ag_2O$ and decreased above 0.2 wt.% $Ag_2O$. At the sintering temperature of $1020^{\circ}C$, electromechanical coupling factor ($k_p$), density, dielectric constant (${\varepsilon}r$) and curie temperature (Tc) of ceramics with 0.2 wt% $Ag_2O$ showed the optimal values of 0.42, $4.33\;g/cm^3$, 738 and $393^{\circ}C$, respectively.

• 한국세라믹학회지
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• 제40권6호
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• pp.539-546
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• 2003

GaN/사파이어 박막구조는 높은 SAW속도로 인해 고주파 소자로 이용될 가능성이 있다. 일반적으로, GaN 박막은 사파이어의 c, a, 그리고 r-면에 성장한다. 본 연구에서는 사파이어의 기판과 GaN 박막사이의 결정학적 관계에 따라 GaN/사파이어 구조의 파동 방정식을 계산하였다. 각각의 면에서, GaN의 kH와 사파이어의 기판방향에 따라 전단속도가 변화하였다. 그 결과 r-면의 경우 전기기계결합계수가 우수했다. 즉, 재료의 탄성상수와 전기기계결합계수는 기판의 cut 방향과 방향성에 좌우된다. 또한, GaN/r-면 사파이어는 전기기계결합계수가 우수하므로 고주파수 대역 SAW 소자 응용에 보다 더 좋을 것이다.

• 한국전기전자재료학회논문지
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• 제20권2호
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• pp.124-129
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• 2007

Dielectric and piezoelectric properties of $0.57Pb(Sc_{1/2}Nb_{1/2})O_{3}-0.43PbTiO_{3}$, which is the morphotropic phase boundary composition for the PSN-PT system, were investigated as a function of $Fe_{2}O_{3},\;Nb_{2}O_{5}\;and\;MnO_{2}$ addition 0 wt% to 0.9 wt%. The maximum dielectric constant of ${\varepsilon}_{33}/{\varepsilon}_{o}=2054$ and the minimum dielectric loss of $tan{\delta}=0.37\;%$ at room temperature were obtained at 0.1 wt% of $Fe_{2}O_{3}$ and 0.5 wt% of $MnO_{2}$ addition, respectively. With addition of 0.5 wt% $Nb_{2}O_{5}$ and $0.5\;wt%\;MnO_{2}$, the electromechanical coupling factor $k_{p}$ and mecanical quality factor $Q_{m}$ were significantly increased, respectively. The maximum electromechanical coupling factor $k_{p}=61.5\;%$ was obtained by addition of $Nb_{2}O_{5}$ and high mechanical quality factor $Q_{m}=919$ was obtained by addition of $MnO_{2}$. The $Q_{m}(=919)$ value is 3.3 times larger than that of non-doped 0.57PSN-0.43PT ceramics.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 추계학술대회 논문집 전기물성,응용부문
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• pp.134-136
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• 2001

In this paper, we investigated the electrical and piezoelectric characteristics of $Pb(Sb,Nb)O_3-Pb(Zr,Ti)O_3$ for piezoelectric transformer and actuator etc. Effect of $WO_3$ addition($0\;wt%{\sim}0.6\;wt%$) on the PSN-PZT ceramic was investigated. Anisotropic properties of electromechanical coupling factor and piezoelectric properties were proved to be varied with amount of $WO_3$ impurity and sintering temperature($1100{\sim}1300^{\circ}C$). The electromechanical coupling factor $k_p$ of 0.41 and the mechanical quality factor am of 1243 were obtained from the specimen with 0.6 wt% $WO_3$ addition sintered at $1100^{\circ}C$ Experimental results indicated that the PZT-PSN ceramics with $WO_3$ impurity can be effectively used for piezoelectric transformer and actuator. etc.