• Journal of the Korean Ceramic Society
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• v.49 no.3
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• pp.253-259
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• 2012

In this study, crystal structural changes and dielectric properties of $(1-x)Pb(Yb_{1/2}Nb_{1/2})O_3-xPbTiO_3$ ((1-x)PYN-xPT) solid solutions were measured and analyzed with respect to the $PbTiO_3$ (PT) contents ($0.40{\leq}x{\leq}0.60$). From X-ray diffraction (XRD) measurements, (1-x)PYN-xPT solid solutions showed changes of the crystal structure from pseudocubic ($0.40{\leq}x{\leq}0.44$) to tetragonal ($0.52{\leq}x{\leq}0.60$) on increasing PT contents and exhibited the coexistence of pseudocubic and tetragonal phase near the morphotropic phase boundary (MPB) composition ($0.46{\leq}x{\leq}0.50$). The dielectric constant showed a maximum value at x = 0.46 and the maximum values in (1-x)PYN-xPT decreased with higher PT contents. The phase transition temperatures of (1-x)PYN-xPT solid solutions increased over the whole composition ranges tested ($0.40{\leq}x{\leq}0.60$).

• Journal of the Korean Ceramic Society
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• v.33 no.4
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• pp.399-404
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• 1996

Hydrothemal synthesis of PbTiO3 has been investigated. A comprehensive thermodynamic model for heteroge-nous reacting solid-aquous system has been used to predict the optimum condition for the synthesis. Synthesis were performed using lead acetate trihydrate as Pb source crystalline TiO2 as Ti source and KOH as minerali-zer. The synthesis has been examined at low temperature (16$0^{\circ}C$) Phase pure perovskite PbTiO3 has been obtained at high pH(above 0.5 mol KOH). The morphology of PbTiO3 was acicular shape. It has been found sible for a distortion in the c direction. The water is gradully released on annealing the powder to 40$0^{\circ}C$ and the normal crystallographic properties are restored.

• The Korean Journal of Ceramics
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• v.4 no.3
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• pp.199-203
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• 1998

$Pb(Zr, Ti)O_3$ (Pb:Zr:Ti=1:0.52:0.48) thin films were prepared on single crystal MgO(100) substrates by dipping-pyrolysis process using a solution of constituent metal naphthenates as starting materials. The solution was spin-coated onto substrate and the precursor films were pyrolyzed at $200^{\circ}C$ in air or at $200^{\circ}C$ in argon for 1, 2, 5 and 24h, followed by final heat treatment at $750^{\circ}C$. For all the films, highly (h00)/(00l)-oriented Pb$Pb(Zr, Ti)O_3$ thin films with smooth surfaces and crack-free were obtained, whereas thin film pyrolyzed in air for 24 h exhibited polycrystalline character. According to the pole-figure analysis, epitaxy of the product films was found to depend on pyrolysis atmosphere.

• Journal of the Korean Ceramic Society
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• v.31 no.5
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• pp.499-504
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• 1994

PbTiO3 thin films were prepared by sol-gel spin coating method using metal alkoxide and diethanolamine (DEA). The precipitation of the PbTiO3 sol occurred at pH 7.3 with HNO3 addition, regardless of the amount of DEA. The gelation time of the PbTiO3 sol was reduced with increasing amount of HNO3 and/or water. When the PbTiO3 films prepared by 0.2 molar coating solution were annealed at $650^{\circ}C$ for 30 min, dense and single phase perovskite films were obtained. Dielectric constant and loss tangent of the film were 239 and 0.01 at 1 kHz, respectively.

• Proceedings of the KIEE Conference
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• 1987.07a
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• pp.439-443
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• 1987

$PbTiO_3$ thin film is prepared by rf sputtering method to implement the pyroelectric infrared detector at room temperature. Annealing of $PbTiO_3$ thin film is done from $400^{\circ}C$ to $550^{\circ}C$ each for 2 hours in furnace. The spectral response to recrystallization process of $PbTiO_3$ thin film is measured by IR photospectro meter. Pyroelectric detector Modeling is studied for implementing device using electrical equivalent circuit model. It is found that $PbTiO_3$ thin film has two IR absorption band within $1000-400\;cm^{-1}$ (10um-25um) and it's spectral response is improved as annealing temperature increase. As a result of pyroelectric detector modeling, we find the possibility of implementing optimum device structure.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.15 no.6
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• pp.499-503
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• 2002

In this study, to develop the high power piezoelectric transformer for adaptor, PSN-PNN-PZT system ceramics were formulated as a function of $MnO_2$ addition and its dielectric and piezoelectric characteristics were investigated. Multi-layer piezoelectric transformer using an excellent composition was also fabricated and its electrical properties evaluated. The composition ceramics added to 0.5wt%$MnO_2$ showed the maximum value of $k_p=0.61$ and $Q_m=1.321$. As the output power of piezoelectric transformer is increased, its temperature rise increased. At the fixed 18W output power, the transformer was stably operated.

• Electrical & Electronic Materials
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• v.3 no.3
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• pp.233-241
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• 1990

본 연구에서는 xPb(Zn$_{1}$3/Nb$_{2}$3/)O$_{3}$-yBa(Zn$_{1}$3/Nb$_{2}$3/)O$_{3}$-zPbTiO(0.50.leq.x.leq.0.60, 0.10.leq.y.leq.0.20, 0.20.leq.z.leq.0.40)세라믹을 1050.deg.C에서 2시간동안 유지시켜 일반소성법으로 제작하였다. 시편 제작시 조성은 조성변태 상경계부근을 선택하였으며 Ba(Zn$_{1}$3/ Nb$_{2}$3/)O$_{3}$ 고용량에 따른 purochlore상의 억제 및 그 영향을 조사하고 구조적, 유전적 및 압전적 특성을 측정하였다. X-선 회절분석 및 미세구조의 관찰 결과, Ba(Zn$_{1}$3/Nb$_{2}$3/)O$_{3}$의 고용량에 따라 pyrochlore상 및 미반응 물질등은 억제되어 0.20mol 고용된 시편에서는 균질한 perovskite상이 형성되었다. Ba(Zn$_{1}$3/Nb$_{2}$3/)O$_{3}$의 고용량이 증가함에 따라 유전상수는 증가하여 0.50PZN-0.20BZN-0.30PT시편의 경우 6880.9의 높은 값을 나타내었으며 정전용량의 온도계수는 감소하여 0.383[%/.deg.C]의 양호한 값을 나타내었다. 큐리온도는 PbTiO$_{3}$의 고용량이 0.20mol에서 0.40mol로 증가함에 따라 30.deg.C에서 170.deg.C로 증가하였다. 전기기계 결합계수 (K$_{p}$), 기계적 품질계수(Qm) 및 압전전하 계수 (d$_{33}$)는 조성변태 상경계 부근의 조성에서 크게 나타났으며 0.60PZN-0.15BZN-0.25PT 시편의 경우 각각 58.5%, 120.5, 150x$10^{-12}$[C/N]의 값을 나타내었다.다.다.

• Applied Science and Convergence Technology
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• v.24 no.6
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• pp.224-227
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• 2015

Ferroelectric $Pb_2(Sc,Nb)O_6$ were prepared under two different sintering conditions using the oxide mixing method and the electrical properties were measured. The sintering conditions were $1350^{\circ}C$ for 25 minutes and $1400^{\circ}C$ for 20 minutes. EDX spectroscopy and XRD were used to determine the crystalline characteristic of the $Pb_2(Sc,Nb)O_6$ compositions Pyrochlore phase showed about 2% in all $Pb_2(Sc,Nb)O_6$ specimens. It expands the growth of crystals in samples sintered at $1400^{\circ}C$ than $1350^{\circ}C$, but all samples were the optimal crystallization. The temperature and frequency dependence of the complex dielectric constant and admittance were measured to analyze the electrical properties. The high dielectric constant of the specimens reflects the good stoichiometry and crystallization. The maximum value of the dielectric constant in the two specimens treated with sintering at $1350^{\circ}C$ and $1400^{\circ}C$ were more than 27,000, and the dielectric loss at room temperature is smaller than 0.05. The maximum dielectric constant decreased with increasing frequency, the transition temperature also increased in $Pb_2(Sc,Nb)O_6$ compositions. The admittance and susceptance values reach a peak at all temperatures, and the magnitude of the peak increases with increasing measuring temperature. Strong frequency dependent of maximum admittance, susceptance, dielectric constant and dielectric loss were observed.

• Journal of Electrochemical Science and Technology
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• v.15 no.1
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• pp.190-197
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• 2024

A commercial PbO₂ mesh cylinder electrode was utilized as the anode for the electrochemical degradation of the textile effluent after the biological treatment with the titanium cylinder as the cathode in a self-made tube electrolyzer. The electrochemical performances of the PbO₂ electrode in tube electrolyzer under different initial pH, electrolyte flow rates, current densities and times of the electrochemical degradation were investigated. The experimental results illustrated that the PbO₂ electrode can reduce the chemical oxygen demand (COD) of the textile effluent from 94.0 mg L^-1 to 65.0 mg L^-1 with the current efficiency of 88.3%, the energy consumption of 27.7 kWh kg^-1 (per kilogram of degraded COD) and the carbon emissions of 18.0 kg CO₂ kg^-1 (per kilogram of degraded COD) under the optimal operating conditions. In addition, the COD of the textile effluent could be reduced from 94.0 mg L^-1 to 22.0 mg L^-1 after the fifth electrochemical degradation. Therefore, PbO₂ mesh cylinder electrode in the tube cylinder was promising for the electrochemical degradation of the textile effluent.

• Journal of the Korean Ceramic Society
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• v.34 no.5
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• pp.500-504
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• 1997

Perovskite Pb0.7Ba0.3Zn1/3Nb2/3O3 substituted with 0.3 mole fraction for Pb-site in PbZn1/3Nb2/3O3 relaxor and pyrochlore Pb1.83Ba0.29Zn1.71Nb2/3O6.39 were mixed and dielectric characteristics of this composites were investigated. Percolation limit of perovskite phase, which was determined by microstructural observation in the composite as an isolation of perovskite phase from pyrochlore matrix, was 28.9-47.5 vol%. Ferroelectric phase transition below percolation limit depends on a parameter which affects the propagation of lattice vibration between isolated perovskite phase and pyrochlore matrix. Therefore, it is believed that ferroelectric lattice vibration of isolated perovskite phase could be transfered to pyrochlore matrix when the oxygen octahedra are linked in 3-dimension and highly polarizable Pb2+ ions are contained in both phases.