• Title/Summary/Keyword: $Sb_2$$O_3$ addition

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Microstructure of High Voltage ZnO Varistors by Various Addition. (다양한 첨가물에 의한 고전압 ZnO 바리스터의 미세구조)

  • O, Su-Hong;Gi, Hyeon-Cheol;Jang, Dong-Hwan;Hong, Gyeong-Jin;Kim, Tae-Seong
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2000.05b
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    • pp.185-189
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    • 2000
  • ZnO varistor has many merits as compared with SiC varistor. But, because of leakage current and non-linear coefficient, it has unstable function properties. For the purpose of improvement of ZnO varistor properties, ZnO varistor is studied according to sintering condition and mixing condition. ZnO varistor, $ZnO-Bi_2O_2-Y_2O_3-MnO-Cr_2O_3-Sb_2O_3$ series, is fabricated with $Sb_2O_3$ mol ratio(0.5-4[mol%]) and sintered at $1250[^{\circ}C]$ In accordance with $Sb_2O_3$ mol ratio and sintering temperature, grain size and non-linear coefficient are measured. The specimen, $Sb_2O_3$ mol ratio is 1[mol%], has small grain size. It has best properties because of its liquid phase shape. When $Sb_2O_3$ mol ratio is 1[mol%], grain size is decreased.

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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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Dielectric and Piezoelectric Characteristics of $0.95(K_{0.5}Na_{0.5})NbO_3$-0.05Li$(Sb_{0.8}Nb_{0.2})O_3$ Ceramics with the amount of $MnO_2$ addition ($MnO_2$ 첨가에 따른 $0.95(K_{0.5}Na_{0.5})NbO_3$-0.05Li$(Sb_{0.8}Nb_{0.2})O_3$ 세라믹스의 유전 및 압전특성)

  • Kim, Do-Hyung;Yoo, Ju-Hyun;Kim, In-Sung;Song, Jae-Sung
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2008.11a
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    • pp.172-173
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    • 2008
  • In this study, $0.95(K_{0.5}Na_{0.5})NbO_3$-0.05Li$(Sb_{0.8}Nb_{0.2})O_3$ + $Ag_2O$ + x wt% $MnO_2$ were investigated as a function of the amount of $MnO_2$ addition in order to improve dielectric and piezoelectric properties of Lead-free piezoelectric ceramics. With increasing the amount of $MnO_2$ addition, density and electromechanical coupling factor $(k_p)$ increased up to 0.3wt.% $MnO_2$ and decreased above 0.3wt.% $MnO_2$. At the sintering temperature of 1020 $^{\circ}C$, Electromechanical coupling factor $(k_p)$, density, dielectric constant $({\varepsilon}r)$ and mechanical quality factor $(Q_m)$ of composition ceramics with 0.4wt% $Ag_2O$ addition showed the optimal value of 0.431, 4.33 g/$cm^3$, 820 and 119, respectively.

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Dielectric and Piezoelectric Characteristics of $(Pb,Ca,Sr)Ti(Mn,Sb)O_3$ Ceramics with the amount of $Bi_2O_3$ addition ($Bi_2O_3$ 첨가량에 따른 $(Pb,Ca,Sr)Ti(Mn,Sb)O_3$ 세라믹스의 유전 및 압전특성)

  • Kim, Do-Hyung;Lee, Sang-Ho;Yoo, Ju-Hyun;Hong, Jae-Il
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2007.06a
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    • pp.292-293
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    • 2007
  • In the study, in order to develop low temperature sintering ceramics for multilayer piezoelectric transformer, $(Pb,Ca,Sr)Ti(Mn,Sb)O_3$ ceramics were fabricated using $Na_2CO_3$, $Li_2CO_3$, $MnO_2$ and $Bi_2O_3$ as sintering aids and their dielectric and piezoelectric properties were investigated according to the amount of $Bi_2O_3$ addition. At the sintering temperature of $900^{\circ}C$, density, thickness vibration mode electromechanical coupling factor ($k_t$), thickness vibration mode mechanical quality factor ($Q_{mt}$) and dielecteic constant (${\varepsilon}_r$) showed the optimum value of $6.94[g/cm^3]$, 0.497, 3,162 and 209, respectively, for multilayer piezoelectric transformer application.

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Sintering and Electrical Properties of Cr-doped ZnO-Bi2O3-Sb2O3 (Cr을 첨가한 ZnO-Bi2O3-Sb2O3계의 소결과 전기적 특성)

  • Hong, Youn-Woo;Shin, Hyo-Soon;Yeo, Dong-Hun;Kim, Jin-Ho
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.23 no.12
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    • pp.942-948
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    • 2010
  • In this study we aims to examine the effects of 0.5 mol% $Cr_2O_3$ addition on the reaction, microstructure development, resultant electrical properties, and especially the bulk trap and interface state levels of ZnO-$Bi_2O_3-Sb_2O_3$ (Sb/Bi=0.5, 1.0, and 2.0) systems (ZBS). The samples were prepared by conventional ceramic process, and characterized by XRD, density, SEM, I-V, impedance and modulus spectroscopy (IS & MS) measurement. The sintering and electrical properties of Cr-doped ZBS (ZBSCr) systems were controlled by Sb/Bi ratio. Pyrochlore ($Zn_2Bi_3Sb_3O_{14}$) was decomposed more than $100^{\circ}C$ lowered on heating in ZBS (Sb/Bi=1.0) by Cr doping. The densification of ZBSCr (Sb/Bi=0.5) system was retarded to $800^{\circ}C$ by unknown Bi-rich phase produced at $700^{\circ}C$. Pyrochlore on cooling was reproduced in all systems. And $Zn_7Sb_2O_{12}$ spinel ($\alpha$-polymorph) and $\delta-Bi_2O_3$ phase were formed by Cr doping. In ZBSCr, the varistor characteristics were not improved drastically (non-linear coefficient $\alpha$ = 7~12) and independent on microstructure according to Sb/Bi ratio. Doping of $Cr_2O_3$ to ZBS seemed to form $Zn_i^{..}$(0.16 eV) and $V^{\bullet}_o$ (0.33 eV) as dominant defects. From IS & MS, especially the grain boundaries of Sb/Bi=0.5 systems were divided into two types, i.e. sensitive to oxygen and thus electrically active one (1.1 eV) and electrically inactive intergranular one (0.95 eV) with temperature.

Behavior of Oxygen Equilibrium Pressure in CRT Glass Melts doped with Sb and Ce ions from the Viewpoint of Fining

  • Kim, Ki-Dong;Kim, Hyo-Kwang;Kim, Jun-Hong
    • Journal of the Korean Ceramic Society
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    • v.44 no.8
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    • pp.419-423
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    • 2007
  • The behavior of oxygen gas participating in fining was observed in CRT (Cathode Ray Tube) glass melts doped with $Sb_2O_5\;or\;CeO_2$ by means of a yttria-stabilized zirconia (YSZ) electrode. The temperature dependence of the oxygen equilibrium pressure ($P_{o2}$) or the activity in both melts showed typical behavior corresponding to a theoretical redox reaction. In other words, the $P_{o2}$ value of melts with $CeO_2$ was lower than that of melts with $Sb_2O_5$ above $1250^{\circ}C$. The result implies that $Sb_2O_5$, is more efficient as a fining agent compared to $CeO_2$. On the other hand, melts from a batch containing $Sb_2O_5\;and\;KNO_3$ showed much higher $P_{o2}$ values compared to melts without $KNO_3$ above $1350^{\circ}C$. It is suggested that the addition of $KNO_3$ to CRT glass batch contributes partly to the first fining of the melts.

Electrodeposition and Characterization of p-type SbxTey Thermoelectric Thin Films (전착법에 의한 p-형 SbxTey 박막 형성 및 열전특성 평가)

  • Park, Mi-Yeong;Lim, Jae-Hong;Lim, Dong-Chan;Lee, Kyu-Hwan
    • Korean Journal of Materials Research
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    • v.21 no.4
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    • pp.192-195
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    • 2011
  • The electro-deposition of compound semiconductors has been attracting more attention because of its ability to rapidly deposit nanostructured materials and thin films with controlled morphology, dimensions, and crystallinity in a costeffective manner (1). In particular, low band-gap $A_2B_3$-type chalcogenides, such as $Sb_2Te_3$ and $Bi_2Te_3$, have been extensively studied because of their potential applications in thermoelectric power generator and cooler and phase change memory. Thermoelectric $Sb_xTe_y$ films were potentiostatically electrodeposited in aqueous nitric acid electrolyte solutions containing different ratios of $TeO_2$ to $Sb_2O_3$. The stoichiometric $Sb_xTe_y$ films were obtained at an applied voltage of -0.15V vs. SCE using a solution consisting of 2.4 mM $TeO_2$, 0.8 mM $Sb_2O_3$, 33 mM tartaric acid, and 1M $HNO_3$. The stoichiometric $Sb_xTe_y$ films had the rhombohedral structure with a preferred orientation along the [015] direction. The films featured hole concentration and mobility of $5.8{\times}10^{18}/cm^3$ and $54.8\;cm^2/V{\cdot}s$, respectively. More negative applied potential yielded more Sb content in the deposited $Sb_xTe_y$ films. In addition, the hole concentration and mobility decreased with more negative deposition potential and finally showed insulating property, possibly due to more defect formation. The Seebeck coefficient of as-deposited $Sb_2Te_3$ thin film deposited at -0.15V vs. SCE at room temperature was approximately 118 ${\mu}V/K$ at room temperature, which is similar to bulk counterparts.

Electrical Properties of lead free (Na,K,Li)(Nb,Sb,Ta)O3 Ceramics with MnO2 Addition (MnO2 첨가량에 따른 비납계 (Na,K,Li)(Nb,Sb,Ta)O3 세라믹스의 전기적특성)

  • Lee, Seung-Hwan;Nam, Sung-Pill;Lee, Dong-Hyun;Lee, Sung-Gap;Lee, Sang-Chul;Lee, Young-Hie
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.60 no.4
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    • pp.801-804
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    • 2011
  • Electrical properties and microstructure were investigated on the effects of $MnO_2$ and the lead-free $(Na_{0.44}K_{0.52}Li_{0.04})(Nb_{0.83}Sb_{0.07}Ta_{0.1})O_3$ ceramics with the addition of $MnO_2$ were fabricated by a conventional mixed oxide method. A gradual change in the crystal and microstructure was observed with the increase of $MnO_2$ addition. For the NKN-LST-xmol%$MnO_2$ sintered at $1100^{\circ}C$, bulk density increased with the addition of $MnO_2$ and showed maximum value at addition 1.0mol% of $MnO_2$. Curie temperature of the NKN-LST ceramics slightly decreased with adding $MnO_2$. The dielectric constant, piezoelectric constant ($d_{33}$) and electromechanical coupling factor ($k_p$) increased below 0.25mol% of $MnO_2$ addition, which might be due to the increase in density. The high piezoelectric properties = 145 pC/N, electromechanical coupling factor = 0.421 and dielectric constant = 2883 were obtained for the NKN-LST-0.25mol%$MnO_2$ sintered at $1100^{\circ}C$ for 4h.

Thermoelectric Characteristics of the p-type $(Bi,Sb)_2Te_3$ Nano-Bulk Hot-Pressed with Addition of $ZrO_2$ as Nano Inclusions ($ZrO_2$를 나노개재물로 첨가한 p형 $(Bi,Sb)_2Te_3$ 나노벌크 가압소결체의 열전특성)

  • Yeo, Y.H.;Kim, M.Y.;Oh, T.S.
    • Journal of the Microelectronics and Packaging Society
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    • v.17 no.3
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    • pp.51-57
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    • 2010
  • Thermoelectric properties of the p-type $(Bi,Sb)_2Te_3$, hot-pressed with the $(Bi,Sb)_2Te_3$ powders fabricated by melting/grinding method, were characterized with variation of the hot-pressing conditions. Thermoelectric characteristics of the hot-pressed $(Bi,Sb)_2Te_3$ were also analyzed with addition of $ZrO_2$ as nano inclusions. With increasing the hotpressing temperature from $350^{\circ}C$ to $550^{\circ}C$, Seebeck coefficient and electrical resistivity decreased from 275 ${\mu}V$/K to 230 ${\mu}V$/K and 6.68 $m{\Omega}$-cm to 1.86 $m{\Omega}$-cm, respectively. The power factor decreased with addition of $ZrO_2$ nano powders more than 1 vol%, implying that the optimum amount of $ZrO_2$ nano inclusions to get a maximum power factor would be less than 1 vol%.