• Journal of the Korean Ceramic Society
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• v.33 no.1
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• pp.17-24
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• 1996

Pb(Mg1/3Nb2/3)O3 powder with high purity chemical homogeniety and reactivity was prepared by solvent eva-poration of common solution. The common solution was fabricated using a Pb(NO3)2 Mg(NO)3 and NB solution which was prepared by dissolving NbC in H2O2 acquous solution. In precusor powder prepared by solvent evaporation method the synthetic temperature of Pb(Mg1/3 Nb2/3)O3 phase was lowered. And the formation of homogeneous Pb(Mg1/3Nb2/3)O3 phase was enhanced but the formation of pyrochlore phase was reduced. The dielectric constant of PMN ceramics from the synthesized powder was found to increase with both sintering temperature and excess MgO and subsequent analysis of the microstructures confirmed that this was due to an increase in grain size. The grain size dependence is explained as a consequence of low-permittivity grain boundaries.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.16 no.8
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• pp.676-680
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• 2003

In this study, to develop the low temperature sintering ceramics for piezoelectric transformer, PSN-PNN-PZT system ceramics were manufactured as a function of V$_2$O$_{5}$ addition, that is the low melting point oxide. Its dielectric and piezoelectric characteristics were investigated. With increasing the amount of V$_2$O$_{5}$ addition, electromechanical coupling factor(kp) and mechanical quality factor(Qm) were decreased. For piezoelectric transformer application, the 0.1wt% V$_2$O$_{5}$ added specimen sintered at 1,00$0^{\circ}C$ showed the proper value of $\varepsilon$r=1,590, kp=0.51 and Qm=748.m=748.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.307-307
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• 2007

압전액츄에이터 및 초음파진동자는 전자제품의 소형화 및 경량화, 의료기기, 모바일기기 및 소형로붓의 발전에 힘입어 그 활용범위가 넓게 확장되고 있다. 1960년 Smolenski등에 의해 $A(B_1,B_2)O_3$형 복합 페로브스카이트 구조를 갖는 강유전성 세라믹스에 대한 연구가 시작된 이래 $Pb(Co,Nb)O_3-Pb(Zr,Ti)O_3$, $Pb(Zn,Nb)O_3-Pb(Zr,Ti)O_3$, $Pb(Mg,Nb)O_3-Pb(Zr,Ti)O_3$ 등 3성분계 세라믹스의 유전, 압전 및 강유전 특성에 대한 많은 연구가 진행되어 왔다. 그러나 압전성이 우수한 세라믹스들은 Pb가 포함되어 있기 때문에 $1000^{\circ}C$ 이상에서 PbO가 급격하게 휘발되는 성질에 따라서 조성의 변동이 생겨 재현성이 어려우며 이를 방지하기 위하여 과잉 PbO를 첨가시키기 때문에 환경오염뿐만 아니라, 경제적인 측면에서도 많은 문제점을 가지고 있다. 소결조제를 이용한 산화물 첨가법은 PbO의 휘발을 억제하는 저온소결 방법중 가장 효과적인 방법으로 알려져 있다. 따라서, 본 연구에서는 적층형 압전액츄에이터로 사용하기위한 저온소결 압전세라믹스를 개발하기 위하여 PZN-PZT세라믹스에 $Li_2CO_3$, $Bi_2O_3$, CuO 를 소결조제로 사용하여 $Li_2CO_3$의 첨가량 변화에 따른 압전 및 유전 특성을 관찰하였다.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.2
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• pp.184-189
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• 2004

The effects of $Y_2$ $O_3$-substitution on the piezoelectric properties of Pb[(N $i_{1}$3/N $b_{2}$3/)$_{0.15}$(Z $r_{1}$2/ $Ti_{1}$2/)$_{0.85}$] $O_3$ceramics were investigated. It was found that $Y^{3+}$ ions incorporate into Pb-sites of the ceramics, resulting in a increased lattice anisotropy and formation of Pb-vacancies. As a result, an orthorhombic-tetragonal phase transition was induced when $\chi$>0.005. At the morphotropic phase boundary of x=0.005, piezoelectric constants( $k_{p}$, $k_{33}$, and $d_{33}$) showed maximum values of 0.53, 0.58, and 350pC/N, respectively. A 30-layer actuator fabricated with the above material showed a maximum strain of 0.12％ under 100V DC bias.

• Bulletin of the Korean Chemical Society
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• v.27 no.5
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• pp.679-686
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• 2006

The positions of $PbI _2$ molecule synthesized into the molecular-dimensioned cavities of $\mid K_6 (Pb _4I_2)(PbI_2) _{0.67}-(H_2O)_2\mid [Si _{12}Al _{12}O _{48}]$-LTA have been determined. A single crystal of $\mid Pb _6\mid [Si _{12}Al _{12}O _{48}]$-LTA, prepared by the dynamic ion-exchange of $\mid Na _{12}\mid [Si _{12}Al _{12}O _{48}]$-LTA with aqueous 0.05 M $Pb _(NO _3)_2$ and washed with deionized water, was placed in a stream of flowing aqueous 0.05 M KI at 294 K for three days. The resulting crystal structure of the product $( \mid K_6 (Pb _4I_2)(PbI_2) _{0.67}(H_2O)_2\mid [Si _{12}Al _{12}O _{48}]$-LTA, a = 12.353(1) $\AA$) was determined at 294 K by single-crystal X-ray diffraction in the space group Pm3 m. It was refined with all measured reflections to the final error index $R_1$ = 0.062 for 623 reflections which $F_o$ > 4$\sigma$($F_o$). 4.67 $Pb ^{2+}$ and six $K^+$ ions per unit cell are found at three crystallographically distinct positions: 3.67 $Pb ^{2+}$ and three $K^+$ ions on the 3-fold axes opposite six-rings in the large cavity, three $K^+$ ions off the plane of the eight-rings, and the remaining one $Pb ^{2+}$ ion lies opposite four-ring in the large cavity. 0.67 $Pb ^{2+}$ ions and 1.34 $I^-$ ions per unit cell are found in the sodalite units, indicating the formation of a $PbI _2$ molecule in 67% of the sodalite units. Each $PbI _2$ (Pb-I = 3.392(7) $\AA$) is held in place by the coordination of its one $Pb ^{2+}$ ion to the zeolite framework (a $Pb ^{2+}$ cation is 0.74 $\AA$ from a six-ring oxygens) and by the coordination of its two $I^-$ ions to $K^+$ ions through six-rings (I-K = 3.63(4) $\AA$). Two additional $I^-$ ions per unit cell are found opposite a four-ring in the large cavity and form $Pb _2K_2I^{5+}$ and $Pb _2K_2I^{3+}$ moieties, respectively, and two water molecules per unit cell are also found on the 3-fold axes in the large cavity.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.8 no.2
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• pp.255-262
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• 1998

This study investigated the crystallization behaviour of sealing amorphous material heat-treated by conventional and microwave heating source. From X-ray diffraction and SEM analyses, it was shown that microwave heat-treated sample had well-grown $PbTiO_3$crystals and the high degree of crystallinity inspite of its heat-treated condition of shorten time and lower temperature as compared with a conventionally heat-treated sample. It was assumed that microwaves inhibit the nucleation of $PbTiO_3$crystal in nucleation stage, but promote the growth of $PbTiO_3$crystal above the critical size of crystal due to enhanced diffusion effect within the sample.

• Journal of the Korean Ceramic Society
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• v.23 no.1
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• pp.60-66
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• 1986

The effect of composition size of sintered body and electrode on resonant characteristics of the system $Pb(Mn_{1/3}Nb_{2/3})O_3 PbTiO_3-PbZrO_3$ has been decribed. Composition ranged from X=40 to X=55 diameter of sintered body ranged from D=6.5 to D=12.5(mm) and diameter of electrode ranged from De=5.5 to De=11 (mm) In the composition of morphotropic phase boundary antiresonant frequency (fa) dcreased slowly whereas resonant frequency (fr) decreased rapidly on the ground of this Δf(fa-fr) and electromechanical coupling fractor Kp increased and Qm showed low value. On the contrary in toward the composition of tetragonal and rhombo-hedral fa increased slowly whereas fr increased rapidly on the ground of this Δf and Kp decreased and Qm increased abruptly. Substance of the above statements have no concern with size of sintered body and ele-ctrode. The other side as the size of electrode decreased Qm fr, fa and Δf increased. Cm and Co dominantly affect the resonant frequency and antiresonant frequency.

• Proceedings of the Korean Ceranic Society Conference
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• 2003.04a
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• pp.186.2-186
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• 2003

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.10 no.2
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• pp.134-139
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• 2000

Ternary system of 40PMN-30PT-30PMW was prepared by using different reaction process. The PMN-PT was synthesized firstly, then it reacted to $PbWO_4$ as PbO and $WO_3$ sources. The dielectric constants were dependent on the density of sintered body and decreased with sintering temperature above $950^{\circ}C$. The highest dielectric constant was 24,000 in a sample sintered at $950^{\circ}C$ with the dielectric loss of 3 %. The temperature dependence of the dielectric constant were decreased with the increase of sintering temperature due to the appearance of double peak maxima. The lowest change in dielectric constant was -37-0 % from -55 to $125^{\circ}C$in a sample sintered at $1150^{\circ}C$ with dielectric constant of 9,900 at room temperature.

• Applied Science and Convergence Technology
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• v.25 no.5
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• pp.88-91
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• 2016

The $Pb[(Mg_{1/3}Ta_{2/3})_{0.7}Ti_{0.3}]O_3$+xwt%PbO systems at temperature of $1250^{\circ}C$ for 4 hours was successful synthesized. In this study, PbO-doped $Pb[(Mg_{1/3}Ta_{2/3})_{0.7}Ti_{0.3}]O_3$ systems with non-linear behaviors showed ordering-degree dependence at the low temperature range were prepared using the columbite precursor method. And the characteristic of remnant polarization vs. electric field were analyzed. The pyroelectric, dielectric and piezoelectric properties of partially disordered $Pb[(Mg_{1/3}Ta_{2/3})_{0.7}Ti_{0.3}]O_3$+xwt%PbO solid solutions were studied as a function of temperature, frequency, and electric field. It showed distinct features of temperature dependent of pyroelectric coefficient, spontaneous polarization and dielectric constant at about $50^{\circ}C$. The figure of merit was calculated as pyroelectric coefficient, dielectric constant and dissipation factor. It was found that the high voltage responsivity FV, high detectivity FD were $0.0373m^2/C$ and $0.6735{\times}10^{-4}Pa{-1/2}$, respectively, in the $Pb[(Mg_{1/3}Ta_{2/3})_{0.7}Ti_{0.3}]O_3$+3.0 wt%PbO system.