• Title/Summary/Keyword: Sb2O3

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Dielectric and Piezoelectric Properties of $Pb(Sb_{1/2}Nb_{1/2})O_3-PbTiO_3-PbZrO_3$ Ceramics ($Pb(Sb_{1/2}Nb_{1/2})O_3-PbTiO_3-PbZrO_3$ 세라믹스에서의 유전 및 압전 특성)

  • Cha, Yoo-Jeong;Kim, Chang-Il;Jeong, Young-Hun;Lee, Young-Jin;Paik, Jong-Hoo
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2008.06a
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    • pp.310-310
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    • 2008
  • 본 연구에서는 (1-x) Pb(Zr0.515Ti0.485)$O_3$ - x Pb$(Sb_{1/2}Nb_{1/2})O_3$ + 0.5wt% $MnO_2$ 조성에 Pb$(Sb_{1/2}Nb_{1/2})O_3$ (PSN) (x=0.02, 0.04, 0.06, 0.08) 변화에 따른 미세구조 및 압전, 유전특성에 관해 고찰하였다. PSN 치환량이 증가함에 따라 정방정 (tetragonal)구조에서 삼방정(rhombohedral)구조로 상전이가 일어났으며, 결정립의 크기가 작아지는 것을 확인하였다. 전기기계결합계수 (kp) 는 PSN이 4 mol % 치환됨에 따라 증가하였으며, 더 이상 치환 시 감소하였다. PSN 치환에 따른 전기적 특성은, 결정구조, 결정립의 크기 및 2 차상 등의 미세구조와 긴밀한 관계가 있는 것으로 보여진다. 상경계(Morphotropic Phase Boundary) 영역인 0.96 Pb(Zr0.515Ti0.485)$O_3$ - 0.04 Pb$(Sb_{1/2}Nb_{1/2})O_3$ + 0.5wt% $MnO_2$ 조성에서 $\varepsilon{^T}_{33}/\varepsilon_o$ = 1109, $k_p$= 70.8 (%), $d_{33}$= 325 (pC/N)의 우수한 특성을 나타내었다.

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Catalytic Oxidation of Carbon Monoxide on Pt and $SnO_2$ (Pt 및 $SnO_2$ 촉매하에서의 일산화탄소의 산화반응)

  • Kwang Yul Choo;Hasuck Kim;Bonghyun Boo
    • Journal of the Korean Chemical Society
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    • v.24 no.3
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    • pp.183-192
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    • 1980
  • Oxidation reactions of carbon monoxide on $SnO_2$, Sb-doped $SnO_2$, and Pt catalyst were studied. The oxidation reaction was found to be first order with respect to both CO and O$_2$ on $SnO_2$ and Sb-doped $SnO_2$ catalysts, and to be of half order on Pt catalyst. A small addition of Sb to $SnO_2$ (depant composition: 0.05∼0.1 mol %) increased the rate of oxidation. On the contrary, a large addition decreased the rate. From the rate expression of oxidation on Pt catalyst, the inhibition effect of carbon monoxide on the rate of oxidation was deduced. The experimentally obtained activatio energies were 5.7 kcal for the Sb doped $SnO_2$ catalyst (dopant composion: 0.05 mole%), and 6.4 kcal for the Pt catalyst. A possible reaction mechanism was proposed from the experimentally obtained kinetic data.

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Characteristics of InSb MIS device prepared by remote PECVD SiO$_{2}$ (Remote PECVD SiO$_{2}$ 를 이용한 InSb MIS 소자의 특성)

  • 이재곤;최시영
    • Journal of the Korean Institute of Telematics and Electronics A
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    • v.33A no.12
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    • pp.59-64
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    • 1996
  • InSb MIS devices prepared by remote PECVD SiO$_{2}$ were fabricated. The SiO$_{2}$ films on InSb were deposited at atemperature range of 67~190$^{\circ}$C. The effects of deposition temperature on the structural characteristics of the SiO$_{2}$ films evaluated Auger electron spectroscopy showed that atomic raito of silicon to oxygen was 0.5 and composition toms were distributed uniformaly throuout the oxide film. The transition region is about 100$\AA$ for SiO$_{2}$/InSb interface. The leakage current density at 1MV/cm and the breakdownelectric field of the MiS device using SiO$_{2}$ film deposited at 105$^{\circ}$C were about 22 nA/cm$^{2}$ and 3.5MV/cm, respectively. The interface-state density at mid-bandgap extracted from 1 MHz high frequency C-V measurement was about 2X10$^{11}$ cm$^{-2}$eV$^{-1}$.

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Effect of SO2 on NOx Removal Performance in Low Temperature Region over V2O5-Sb2O3/TiO2 SCR Catalyst Washcoated on the Metal Foam (저온영역에서 메탈폼에 코팅된 V2O5-Sb2O3/TiO2 SCR 촉매의 NOx 저감성능에 미치는 SO2 영향에 관한 연구)

  • Na, Woo-Jin;Park, Young-Jin;Bang, Hyun-Seok;Bang, Jong-Seong;Park, Hea-Kyung
    • Clean Technology
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    • v.22 no.2
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    • pp.132-138
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    • 2016
  • The emission of SO2 is inevitable in case of combustion of most fossil fuels except LNG in commercial power plant which has a bad effect on the durability of SCR catalyst. To develop a low temperature SCR catalyst which has a high NOx removal performance and excellent durability to SO2, V2O5/TiO2 catalysts were prepared by coating on the metal foam substrate with the impregnation amount of Sb2O3 as promotor. This study has evaluated the NOx removal performance and the durability to SO2 on a laboratory scale atmospheric reactor and analyzed the properties of the prepared catalysts by means of porosimeter, BET, SEM (scanning electron microscope), EDX (energy dispersive x-ray spectrometer), XPS (X-ray photoelectron spectroscopy). It was found that the surface area of catalyst increased with the impregnation amount of Sb2O3 and the NOx removal performance showed the highest value at the 2 wt% impregnation of Sb2O3. This results was considered to be due to the optimum active site on the catalyst surface. And also, Sb2O3 impregnated catalysts presented that NOx removal performance was maintained despite the exposure to SO2 for 5 hours. Therefore it was confirmed that metal foam SCR catalyst for low temperature could be manufactured with the optimum control of Sb2O3 impregnation according to the SO2 presence or not.

The Microstructure and Electrical Properties in the Pb(Sb1/2 Nb1/2)O3-PbTiO3-PbZrO3 System with MnO2 Addition (Pb[(Sb1/2 Nb1/2)0.08 Zr0.49 Ti0.48]O3에서의 MnO2 첨가에 따른 미세구조와 전기적 물성변화에 대한 연구)

  • 강원호;박원규;김호기
    • Journal of the Korean Ceramic Society
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    • v.24 no.6
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    • pp.537-542
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    • 1987
  • The microstructure and electrical properties of Pb[(Sb1/2 Nb1/2)0.08 Zr0.49 Ti0.48]O3 with MnO2 addition have been investigated in this work. The amount of MnO2 addition was 0, 0.4, 0.8, 1.2, 2.0 wt%, respectively. The soild solution range of MnO2 that assumed in this composition according to thevariations of micro-structure and electrical properties was 0.4-0.8 wt%.

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A Study on the Pyroelectric Properties of the Pb($Sb_{1/2}Sn_{1/2}O_3-PbTiO_3-PbZrO_3$ Ceramics (Pb($Sb_{1/2}Sn_{1/2}O_3-PbTiO_3-PbZrO_3$ 세라믹의 초전특성에 관한 연구)

  • 윤종원;이성갑;배선기;이영희
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 1989.06a
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    • pp.74-76
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    • 1989
  • x Pb($Sb_{1/2}Sn_{1/2}O_3-PbTiO_3-PbZrO_30.05{\leq}x{\leq}0.25$) ternary compound ceramics were fabricated by the mixed oxide method. The sintering temperature and time were 1200-1270[$^{\circ}C$], 2 hour, respectively. Increasing the PSS contents, the transition temperatures were decreased. The relative dielectric constant and Curie temperature of the 0.25 PSS-0.25 PT-0.5 PZ specimens were 450, 220[$^{\circ}C$]. The Pyroelectric coefficient of the 0.25PSS-0.25PT-0.50 PZ specimen was $5.20{\times}10^4$[C$\textrm{cm}^2$K].

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The Structure and Electrical Characteristics of ZnO Varistors Surface using-Fractal (프랙탈을 이용한 ZnO 바리스터 표면 구조 및 전기적 특성)

  • Oh, Soo-Hong;Hong, Kyung-Jin;Lee, Jin;Lee, Joon-Ung;Kim, Tae-Sung
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.13 no.10
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    • pp.834-839
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    • 2000
  • The structural properties that SEM photograph of ZnO varistors surface studied by fractal mathematics program were investigated to verify the relations of electrical characteristics. The SEM photograph of ZnO varistors surface were changed by binary code and the grain shape of that were analyzed by fractal dimension. The void of ZnO varistors surface was found by fractal program. The relation between grain density and electrical properties depend on fractal dimension. The grain size in ZnO varistors surface was decreased by increasing of Sb$_2$O$_3$ addition. The spinel structure was formed by Sb$_2$O$_3$addition and it was depressed the ZnO grain formation. The grain size of ZnO by Sb$_2$O$_3$addition were from 5 to 10[${\mu}{\textrm}{m}$]. Among of ZnO varistors, fractal dimension of ZnO4 was very high as a 1.764. The density of grain boundary in ZnO2 and ZnO3 varistors surface was 15[%] by formed spinal structure. The breakdown electric field of ZnO2 that fractal dimension has 1.752 was very high to be 8.5[kV/cm]. When the fractal dimensin was high, the grain shape of ZnO varistors was complex and the serial layers of ZnO grain was increased.

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H2 gas sensing characteristics of SnO2 nano-powdersprepared by homogeneous precipitation method (균일침전법을 이용한 SnO2 나노분말의 H2 감지 특성)

  • Kim, Yeong-Bok;Lee, Woon-Young;Park, Jin-Seong
    • Journal of Sensor Science and Technology
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    • v.17 no.5
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    • pp.361-368
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    • 2008
  • Nanosized $SnO_2$ particles were synthesized by homogeneous precipitation method using tin chloride ($SnCl_4{\cdot}5H_{2}O$) and urea ($CO(NH_2)_2$). The powders were heated at $500^{\circ}C$ and $600^{\circ}C$ for 2h. The crystal structure, microstructure, thermal behavior, specific surface area were analyzed using XRD, FE-SEM, TGA and BET, respectively. The initial resistance and the $H_2$ sensing properties were measured as a function of ${Sb_2}{O_3}$ and Pd doping concentrations. The resistance was decreased with the addition of ${Sb_2}{O_3}$ and the sensitivity for $H_2$ gas was increased with the addition of Pd. Thus, the optimum $H_2$ gas sensing property was obtained in the 0.25.mol% ${Sb_2}{O_3}$ and 1.w% added $SnO_2$ powders.

Effects of the Thickness and Dopant on the Photoelectro- chemical Conversion in the Polycrystalline $TiO_2$ Electrodes (광전기 화학변환에 미치는 $TiO_2$ 전극의 두께와 첨가제의 영향)

  • 윤기현;강동헌
    • Journal of the Korean Ceramic Society
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    • v.21 no.3
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    • pp.266-270
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    • 1984
  • The photoelectrochemical properties of the reduced $TiO_2$ceramic electrodes are investigated varying the thickness of the electrodes and the amounts of $Sb_2O_3$ as dopant. As the thickness of the undoped. $TiO_2$ceramic electrode increases the photocurrent tends to decrease. However for the R-F sputtered $TiO_2$ thin film electrodes the photocurrent tends to increase to about 1$\mu\textrm{m}$ thick and then decreases with increasing thickness. For the $TiO_2$ ceramic electrodes doped with $Sb_2O_3$ the photocurrent decreases with inreasing the amounts of dopant and in the case of rapid cooling in air without reduction treatment the photocurrent shows lower value. Also visible light excitation is observed at 500~550(nm) wavelength for the $TiO_2$ ceramic electrodes doped with $Sb_2O_3$comparing wtih the $TiO_2$ ceramic electrodes (~420nm)

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A Study on the Dielectric and Pyroelectric Properties of the PSS-PT-PZ Ceramics Added $MnO_2$ ($MnO_2$가 첨가될 PSS-PT-PZ 세라믹의 유전 및 초전특성에 관한 연구)

  • Lee, Sung-Gap;Ryu, Ki-Won;Lee, Young-Hie;Bae, Seon-Gi;Park, Chang-Yub
    • Proceedings of the KIEE Conference
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    • 1991.07a
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    • pp.194-197
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    • 1991
  • In this study, $(Pb_{0.99}La_{0.01})[(Sb_{1/2}Sn_{1/2})_{0.10}Ti_{0.25}Zr_{0.65}]O_3$, added $MnO_2$ (0-0.30[mol%]) ceramics were fabricated by the mixed oxide method. The sintering temperature and time were $1250[^{\circ}C]$, 2[hr], respectively. In the $(Pb_{0.99}La_{0.01})[(Sb_{1/2}Sn_{1/2})_{0.10}Ti_{0.25}Zr_{0.65}]O_3$ added $MnO_2$ (0.24[mol%]) specimens, relative dielectric constant and dielectric loss were minimum values 3.52, 0.003, respectively, and Curie temperature were highest values $256[^{\circ}C]$. Pyroelectric coefficient and voltage responsivity of the $(Pb_{0.99}La_{0.01})[(Sb_{1/2}Sn_{1/2})_{0.10}Ti_{0.25}Zr_{0.65}]O_3$, and added $MnO_2$ (0.24[mol%]) specimen were good values, $6.73{\times}10^{-8}[C/cm^2K],\;125[v/W]$, respectively. Figure of merit of pyroelectric current, voltage and detectivity of the specimen, $(Pb_{0.99}La_{0.01})[(Sb_{1/2}Sn_{1/2})_{0.10}Ti_{0.25}Zr_{0.65}]O_3$ added $MnO_2$ (0.24[mol%]) were good values $2.714{\times}10^{-8}[Ccm/J],\;7.706{\times}10^{-11}[Ccm/J],\;2.640{\times}10^{-8}[Ccm/J]$, respectively. Voltage responsivity of the $(Pb_{0.99}La_{0.01})[(Sb_{1/2}Sn_{1/2})_{0.10}Ti_{0.25}Zr_{0.65}]O_3$ added $MnO_2$ (0.24[mol%]) specimens were decreased with increasing the chopper frequency.

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