• 한국결정성장학회지
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• 제15권6호
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• pp.244-251
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• 2005

수열합성법에 의해 제조된 티탄산바륨 (BT01, BT02, BT03, BT04, BT05)의 입자크기와 분체특성과의 상관관계를 비표면적, 제타전위, XPS, XRD 및 SEM에 의해 조사하였다. 레이져광산법에 의해 측정된 입자의 크기는 비표면적과 XRD를 통해 결정된 격자이방성과 밀접한 관계가 있음을 보였다. 분말의 비표면적은 입자의 크기가 증가함에 따라 감소하였으며, BT03 시료는 동일한 입자크기의 BT04에 비하여 큰 비표면적을 보였으며, 이는 입자들의 응집에 기인하는 것으로 SEM사진 및 XRD 분석을 통하여 밝혀졌다. 입자의 크기가 증가함에 따라 제타전위는 증가하는 경향을 보였으며, BT02와 BT03 분말은 다른 분말에 비하여 제타전위가 큰 음의 값을 나타내었다. XPS 분석결과 분쇄시 티탄산바륨과 물 사이의 반응에 의한 $Ba^{2+}$ 이온의 용출과 관련이 있는 것으로 분석되었다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2009년도 추계학술대회 논문집
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• pp.84-84
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• 2009

$BaTiO_3$는 perovskite 구조를 가지는 대표적인 강유전체 재료로서 MLCC (Multi Layer Ceramic Capacitor), PTC thermistor등에 널리 사용되어지고 있다. 최근 고용량 MLCC의 상업화와 함께 나노크기를 갖는 tetragonal phase의 $BaTiO_3$ 입자를 합성하기 위한 다양한 제조방법이 제시되고 있다. 또한 유전특성과 온도특성 및 신뢰성을 향상시키기 위해 많은 첨가제들이 연구되어지고 있다. 따라서 본 연구에서는 희토류 원소인 $Y_2O_3$를 첨가하여 유전특성 및 온도특성을 향상시키고자 하였다. 본 실험에서는 150nm 크기를 갖는 pure $BaTiO_3$ 분말을 사용하고 $Y_2O_3$의 양은 0.02 ~ 0.1wt%로 변수를 주어 첨가하였으며, 최적의 소결 조건을 찾기 위하여 1200, 1230, $1250^{\circ}C$에서 소결을 진행하였다. 실험방법으로는 균일한 혼합을 위하여 Iso-alcohol을 이용하여 48시간 ball-mill 하였으며 오븐에서 건조 후 ${\Phi}15$로 성형하여 소결을 진행하였다. 실험결과로는 $Y_2O_3$ 첨가량이 0.02wt% 부터 상온부터 상전이 온도 부근의 유전율 기울기는 완만해 지는 것을 확인할 수 있었으며, 소결시편의 정방정비 (tetragonality)도 뚜렷하게 나타났다. $Y_2O_3$ 첨가랑이 0.1 wt% 일 때는 첨가량의 증가로 인해 강유전성이 상쇄됨을 나타냈다. 이는 $2450^{\circ}C$에 이르는 매우 높은 용융온도와 $2350^{\circ}C$까지 상전이가 는 $Y_2O_3$를 미량 첨가할 때, 고온에서 높은 화학적 안정성과 내열성을 가져 온도 안정성이 향상된 것으로 판단된다.

• 센서학회지
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• 제6권3호
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• pp.188-193
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• 1997

La 조성이 $5{\sim}15%$이고 PbO과잉인 PLT 타겟을 이용하여 MgO(100) 단결정 기판위에 고주파 마그네트론 스펏터링법으로 PLT 박막을 제조하였으며, 고온 XRD 분석을 하였다. 제조조건은 기판온도를 $580^{\circ}C$, 분위기압을 10mTorr, 고주파 전력밀도를 $1.7W/cm^{2}$ 및 $Ar/O_{2}$를 10/1로 하였을 때 PLT 박막들은 La 농도가 증가할수록 c-축 성장율과 정방정형성(c/a)이 감소하였고 확산형 상전이 특성을 나타내었다. 이러한 PLT 박막을 이용하여 초전형 적외선 센서를 제조하였으며, 이력특성과 광특성을 측정하였다. 제조된 적외선 센서는 $1.71{\mu}C/cm^{2}$ 이상의 잔류 분극도를 보였고 500 mV이상의 초전전압을 보였으며 신호대 잡음비는 10:1 이하로 낮았다.

• 한국재료학회지
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• 제14권11호
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• pp.764-768
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• 2004

Perovskite Pb(Mn_{1/3}Sbu_{2/3})O_2-Pb(Zr,Ti)O_3\;(PMS-PZT) was prepared and ZnO doping effects on its piezoelectric properties were investigated. Pyrochlore phase was not identified in the PMS-PZT ceramics with $0\sim5\;mol\%$ ZnO sintered at $1100^{\circ}C$ for 2 hrs, and maximum sintered density of $7.92 g/cm^3$ was obtained. Piezoelectric charge constant and voltage constant increased to $359{\times}10^{-12}\;C/N\;and\;22.5{\times}10^{-13}\;Vm/N$, respectively, with increasing ZnO content. Mechanical quality factor reduced considerably with increasing ZnO content. When the ZnO content was 3 $mol\%$, electromechanical coupling factor and relative dielectric constant showed maximum values of $56\%$ and 1727, respectively. This should be evaluated by complicated variations of sintered density, tetragonality of lattice, grain size, and A-site vacancy generated by ZnO addition and $Zn^{2+}$ substitution.

• 한국세라믹학회지
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• 제42권2호
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• pp.123-126
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• 2005

용매열법으로 출발물질의 농도를 변수로 차여 $BaTiO_3$ 분말을 합성하였다. 평균입자크기는 출발물질의 농도에 따라 비례하였는데 TiO_2를 기준으로 1/16M 농도에tj 59nm이었고 1/2M 농도에서는 89nm까지 증가하였다. 평균입자 크기가 89nm인 BT 분말에 대하여 리트벨트법에 의하여 분석한 결과 상분율은 정방정상 $75.5\%$이었고, 격자상수는 정방정상은 a=0.3999(nm), c=0.40319(nm)이고, 입방정상은 a=0.4015(nm)이었다. 이 분말을 $500^{\circ}C$ 1시간 열처리 후 TEM분석을 한 결과, 분말 내부에 수산 이온들이 거의 존재하지 않음을 확인하였다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1996년도 추계학술대회 논문집
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• pp.54-58
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• 1996

In this paper, the structure, dieletric and piezoelectric properties of Pb(Fe$_{\frac{1}{2}}$/Sb$_{\frac{1}{2}}$$O_3$+ Pb(Zr$_{0.52}$ Ti$_{0.48}$ )O$_3$system ceramics were investigated and the effects of donor Nb$^{+5}$ on these properties were characterized for the application of the actuator. In xPb(Fe$_{\frac{1}{2}}$Sb$_{\frac{1}{2}}$)O$_3$+ (1-x) Pb(Zr$_{0.52}$ Ti$_{0.48}$ )O$_3$system ceramics, tetragonality decreased as x and Nb$_2$O$_{5}$ wt% were increased. In 0.05Pb(Fe$_{\frac{1}{2}}$Sb$_{\frac{1}{2}$}$)O$_3$+ 0.95 Pb(Zr$_{0.52}$ Ti$_{0.48}$ )O$_3$system, grain size was smallest but showed best dielectric and piezoelectric properties. The specimen sintered at 120$0^{\circ}C$ in 0.05pb(Fe$_{\frac{1}{2}}$Sb$_{\frac{1}{2}}$ )O$_3$+ 0.95 Pb(Zr$_{0.52}$ Ti$_{0.48}$ )O$_3$+ Nb$_2$O$_{5}$ 0.6wt% exihibited best piezoeletric properties such as $K^{p}$ =64%, d$_{33}$ =490 [$\times$10$^{-12}$ C/N] and strain was 1320[$\times$10$^{-6}$ Δ$\ell$/$\ell$]at AC 6kV/cm

• 한국세라믹학회지
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• 제20권4호
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• pp.315-323
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• 1983

Effect of NiO and $MnO_2$ addtivies on the dielectric piezoelectrics and polarization-reversal properties of $(Pb_{0.936} La_{0.064})$$(Zr_{0.60}Ti_{0.40})O_3$ ceramics have been investigated. The specimens were prepared by the mixed oxide techni-que and atmosphere sintering method. The room temperature X-ray diffraction studies show that perfect perovskite solution with tetragonal structure was obtained from PLZT and its additives. The dielectric constant and dissipation factor decreased with the addition of both NiO and $MnO_2$ The Curie of Curie temperature was not observed but they displayed broadened maxima. The planar coupling factor was improved by addition of NiO and also increased with increasing sintering time carried out at 105$0^{\circ}C$ Addition of $MnO_2$ yielded a markedly high mechanical quality factor. The space-charge field decreased with the addition of NiO but increased with the addition of $MnO_2$ The planar coupling factor and space-charge field showed same dependence on the additivies. The tetragonality Curie temperature and planar coupling factor of $(Pb_{0.936} La_{0.064})$$(Zr_{0.60}Ti_{0.40})O_3$ were higher than those of $(Pb_{0.936} La_{0.064})$$(Zr_{0.568}NU_{0.032}Ti_{0.40})_{0.984}O_3$ but the grain size lattic parameter dielectric constant dissipation factor mechanical quality factor and space-charge field of the former were lower than those of the latter.

• 대한전기학회논문지
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• 제41권5호
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• pp.508-516
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• 1992

In this study, dielectric and piezoelectric properties of 0.05Pb(AlS12/3TWS11/3T)OS13T-0.95Pb(ZrS10.52TTiS10.48T)OS13T system ceramics were investigated with respect to the variations of MnOS12T and FeS12TOS13T additions amounts. The results obtained in this study are summarized as follows: 1. As the amounts of MnOS12T and FeS12TOS13T are increased, tetragonality(c/a) and apparent density were decreased but grain size was increased, also the limits of solubility were revealed because pores were formed at the amounts of 0.3wt% MnOS12T and 0.5wt% FeS12TOS13T. 2. AS the increasing of amounts of MnOS12T and FeS12TOS13T, the temperature of phase transition(TS1cT) was decreased, and pemeability had maximum value at the amount of 0.3wt% MnOS12T but were sharply decreasd for the increasing FeS12TOS13T amounts. 3. As the amounts of MnOS12T and FeS12TOS13T are increased, the electro-mechanical coupling factor(kS1pT) was decreased from 60% to 41%, 19% respectively, but mechanical quality factor(QS1mT) had maximum values 720 for amount of 0.3wt% MnOS12T and 320 the amount of 0.5wt% FeS12TOS13T.

• 한국전기전자재료학회논문지
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• 제13권3호
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• pp.214-219
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• 2000

In this paper the structural dielectric and piezoelectric properties of Pb［(M $g_{1}$2// $W_{1}$2/)$_{x}$-(N $i_{1}$3//N $b_{2}$3/)$_{0.15-x-(Zr_{0.5})}$ $Ti_{0.5}$)$_{0.85}$］ $O_3$ (x=0.0~0.10) ceramic were investigated with the substitution of Pb(M $g_{1}$2// $W_{1}$2/) $O_3$. According to the substitution of Pb(M $g_{1}$2//W/1/2/) $O_3$ curie temperatures were slightly decrease due to the decrease of the tetrag-onality of crystal structure and coercive fields were decreased. Up to the substitution of Pb(M $g_{1}$2// $W_{1}$2/) $O_3$ 3mol%,remnant polarization dielectric constant piezoelectric constant were increased. Dielectric constant and electro-mechanical coupling factor( $k_{p}$, $k_{31}$ ) were appeared the highest value of 2230, 0.64, and 0.38 and piezoelectric constant( $d_{33}$ , $d_{31}$ ) was the largest value of 418, 202($\times$10$^{-12}$ /C/N), respectively, when the substitution amount of Pb(M $g_{1}$2// $W_{1}$2/N) respectively, when the substitution amount of Pb(M $g_{1}$2// $W_{1}$2/) $O_3$ was 3mol%.s 3mol%.%.

• 한국전기전자재료학회논문지
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• 제26권3호
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• pp.204-208
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• 2013

In this study, $KNbO_3$-substituted (Li,Na,K)(Nb,Sb,Ta)$O_3$ ceramics were investigated to develop Pb-free composition ceramics for multilayer actuator and energy harvester applications. The X-ray diffraction analysis indicated that all samples were pure perovskite phase and no secondary phase was found. A tetragonality as a function of $KNbO_3$ substitution showed the maximum value at 1.5 mol% $KNbO_3$ and then decreased. The SEM image analysis showed the maximum grain size of $3.14{\mu}m$ at 1.5mol% $KNbO_3$. In the composition ceramics with 1.5 mol% $KNbO_3$ sintered at $1,100^{\circ}C$, excellent properties of density= 4.75 $g/cm^3$, electromechanical coupling factor ($k_p$)= 0.50 and piezoelectric constant($d_{33}$)= 290 pC/N were obtained, respectively, suitable for piezoelectric actuator and energy harvester applications.