• Title/Summary/Keyword: $Co/SiO_{2}$

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Clay Mineralogy and Geochemistry of a Sediment Core from the Seamount to the South of Antarctic Polar Front, Drake Passage (남극 드레이크해협 극전선 남부 해산 퇴적물 코어의 점토광물 및 지구화학적 특성)

  • Jeong, Gi-Young
    • Journal of the Mineralogical Society of Korea
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    • v.19 no.3 s.49
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    • pp.163-169
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    • 2006
  • Mineralogy and geochemistry of the sediment core from the seamount (2710 m below the sea level) just south of the Antarctic Polar Front were examined to draw paleoceanographic information in glacial-interglacial cycles. Smectite was most abundant clay mineral associated with illite and chlorite. Its content was slightly higher below 170 cm, suggesting a boundary between isotope stage 4 and 5. Si, Zr, Cs, Th, REE, $K_{2}O$, and $Al_{2}O_{3}$ show complete antithetical distribution with respect to $CaCO_{3}$ through the core. $SiO_{2}$ maxima and $CaCO_{3}$ minima at depths of 24, 136, and 176 cm are probably correlated with massive influx of ice-rafted debris during the advance of Antarctic ice shelves. Ni, Cu, and Ba show rather little correlation with $SiO_{2}$, suggesting their relation to biogenic debris, precipitation from seawater, or hydrothermal input. Particularly, Ba maxima tend to lag $10{\sim}20cm$ after $SiO_{2}$ maxima, probably due to rapid increase of productivity following deglaciation.

Chemical Solution Deposition 방법으로 증착된 $Bi_{0.8}A_{0.2}FeO_3$ (A=Pb, Co) 박막의 자기적 특성에 대한 연구

  • Cha, Jeong-Ok;An, Jeong-Seon
    • Proceedings of the Korean Vacuum Society Conference
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    • 2011.08a
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    • pp.245-245
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    • 2011
  • $BiFeO_3$ (BFO)박막에 전위금속 Pb와 Co를 각각 치환환 박막을 chemical solution deposition 방법으로 Pt/Ti/SiO2/Si(100) 기판위에 증착하였다. Bi 자리에 Pb와 Co를 20 at.% 치환하였으며, 치환된 $Bi_{0.8}Pb_{0.2}FeO_3$ (BPFO), $Bi_{0.8}Co_{0.2}FeO_3$ (BCFO) 박막의 구조적, 자기적 특성 변화를 BFO 박막과 비교하여 조사하였다. XRD 패턴을 분석한 결과 BPFO, BCFO 박막들은 모두 rhombohedrally distorted perovskite 구조였으며 불순물인 pyrochlore 상이 약하게 관측되었다. 치환이 이루어진 BPFO, BCFO 박막들의 자기 이력곡선은 안정된 포화곡선을 나타냈으며 BFO의 포화값(5 emu/$cm^3$)에 비해 크게 증가된 55 emu/$cm^3$, 35 emu/$cm^3$의 값을 나타냈다. 또한 보자력장(coercive field, Hc)값도 BFO의 500 Oe보다 크게 증가된 1,200 Oe, 800 Oe의 값을 보였다.

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Effects of $SiO_2$ and Seed on Ba-ferrite Synthesized by Molten Salt (용융염법으로 합성한 Ba-ferrite의 $SiO_2$ 및 Seed 첨가 효과)

  • 김영근;이승관;김현식;오영우
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 1996.11a
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    • pp.326-329
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    • 1996
  • In order to synthesize Ba-ferrite fine particles by molten salt method and inhibit the abnormal grain growth of sintered specimen, KCI anti NaCl were added to basic composition to 50% by weight, and added 1 male% of $SiO_2$ to control the shape of Ba-ferrite particles. $H_{c}$ and $M_{r}$ were decreased when F $e^{3+}$ was substituted with $Co_{2+}$ and $Ti_{4+}$ from x=0 to x=1.0 in $BaFe_{12-2x}$ $Ti_{x}$ $Co_{x}$ $O_{19}$ , and 1 mole% $SiO_2$ increased the size but shortened c-axis of hexagonal ferrite. Seeds added in Ba-ferrite particle effected inhibition of abnormal grain growth during sintering.ing.g.

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Synthesis and photoluminescence of Ca3Si3O8F2: Ce4+, Eu3+, Tb3+ phosphor

  • Suresh, K.;PoornachandraRao, Nannapaneni V.;Murthy, K.V.R.
    • Advances in materials Research
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    • v.3 no.4
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    • pp.227-232
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    • 2014
  • $Ce^{4+}$, $Eu^{3+}$, $Tb^{3+}$ co-doped $Ca_3Si_3O_8F_2$ phosphor was synthesized via solid state reaction method using $CaF_2$, $CaCO_3$ and $SiO_2$ as raw materials for the host and $Eu_2O_3$, $CeO_2$, and $Tb_4O_7$ as activators. The luminescent properties of the phosphor was analysed by spectrofluorophotometer at room temperature. The effect of excitation wavelengths on the luminescent properties of the phosphor i.e. under near-ultraviolet (nUV) and visible excitations was investigated. The emission peaks of $Ce^{4+}$, $Eu^{3+}$, $Tb^{3+}$ co-doped $Ca_3Si_3O_8F_2$ phosphor lays at 480(blue band), 550(green band) and 611nm (red band) under 380nm excitation wavelength, attributed to the $Ce^{4+}$ ion, $Tb^{3+}$ ion and $Eu^{3+}$ ions respectively. The results reveal that the phosphor emits white light upon nUV (380nm) / visible (465nm) illumination, and a red light upon 395nm / 535nm illumination. RE ions doped $Ca_3Si_3O_8F_2$ is a promising white light phosphor for LEDs. The emission colours can be seen using Commission international de l'eclairage (CIE) co-ordinates. A single host phosphor emitting different colours under different excitations indicates that it is a potential phosphor having applications in many fields.

Carbonation of a few of Common materials which can fix CO2 (상용 CO2고정재료의 탄산화에 관한 문헌적 연구)

  • Chen, zheng-xin;Lee, Han-Seung
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2016.10a
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    • pp.47-48
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    • 2016
  • Mineral carbonation technology is a process whereby CO2 is chemically reacted with calcium-and/or magnesium-containing minerals to form stable carbonate materials. Add the Materials that could fix CO2 as mineral admixture to concrete can improve the anti-carbonation properties of concrete. This paper has carried on the literature research on the carbonated mechanism of Material that could fix carbon dioxide. Such as Brucite, 𝜞-C2S, Mg2SiO4, MgO, Ca3MgSi2O8. And summarizes the development of the development of this field.

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A study of sintering behavior of spray coating in CaO-Al2O3-SiO2 glasses on Al2O3 substrate (CaO-Al2O3-SiO2 계 유리 스프레이 코팅막의 소성 거동에 대한 연구)

  • Na, Hyein;Park, Jewon;Park, Jae-Hyuk;Kim, Dae-Gun;Choi, Sung-Churl;Kim, Hyeong-Jun
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.29 no.6
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    • pp.298-307
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    • 2019
  • Two types of CaO-Al2O3-SiO2 (CAS) glass powder applied spray coating on the surface of sintered Al2O3 were researched for sintering behavior; (1) Si-rich, glass containing high content SiO2, (2) Ca-rich, containing high content CaO. Foaming of bubbles remaining inside the Ca-rich glass was produced at a viscosity of approximately 107~109 poise, resulting in decreasing shrinkage (interfering with sintering) and increasing surface roughness. In case of Si-rich glass, there was no serious foaming bubbles phenomenon like Ca-rich below 1000℃, however cristobalite crystals with low density occurred at 1200℃ and then produced re-foaming of bubbles, resulting in abnormal sintering behavior. These phenomenon is considered to be a decrease in viscosity due to an increase in the Ca content of the glass according to the formation of low-density cristobalite crystals. Therefore, in case of CAS glass, it is necessary to consider the increase of surface roughness and the sintering interference because of foaming bubbles phenomenon at low temperature sintering. Especially, when containing high SiO2 content, abnormal foaming phenomenon due to crystallization at high temperature should be predicted.

Reactions of Various Ceramic Materials with Cobalt Sulfate Solution (황산코발트 용액에 의한 다양한 세라믹소지의 반응)

  • Won, Il-An;Kim, Kyung-Nam
    • Korean Journal of Materials Research
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    • v.24 no.2
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    • pp.93-97
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    • 2014
  • In this study, a cobalt sulfate ceramic coating was sintered on various clays at $1250^{\circ}C$. The specimen characteristics were investigated by X-ray diffraction(XRD), scanning electron microscopy(SEM), TG-DTA, UV-vis spectrophotometer, and HRDPM. The ceramic coating had a constant thickness of thousands ${\mu}m$, and the surface was confirmed to be densely fused. Other new compounds were produced by the cobalt sulfate sintering process and reactions. These compounds were a $CoAl_2O_4$ phase, $Co_2SiO_4$ phase, anorthite($CaAl_2Si_2O_8$) phase, and $FeAl_2O_4$ phase, respectively. UV properties of the coated specimen were investigated, celadon clay specimen in 530-550 nm band is showing a dark gray color. The white clay and white mix clay specimen in 460-500 nm band is showing a blue color. The cobalt-aluminate($CoAl_2O_4$) spinel and the cobalt-silicate olivine($Co_2SiO_4$) were the strongest of the ceramic pigments, producing a very pure, navy blue color.

Assessment for $CO_2$ Biomineralization Characteristics and its Applicability for Solidified Sludge (이산화탄소 생광물화 특성 및 슬러지 고화물 적용성 평가)

  • Min, Dong-Hee;Ahn, Chang-Min;Han, Ji-Sun;Yoon, Soon-Uk;Jeon, Eun-Jeong;Won, Jong-Choul;Chun, Seung-Kyu;Kim, Chang-Gyun
    • Journal of Korean Society of Environmental Engineers
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    • v.33 no.11
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    • pp.812-820
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    • 2011
  • This study was conducted to characterize $CO_2$ biomineralization on several minerals (i.e., CaO, MgO, $SiO_2$) by bottle test in an aqueous solution and solidified sludge using different aerobic bacterial strains like Bacillus megaterium and Bacillus pasteurii by batch test. These bacteria promote the formation of microenvironments that facilitate the precipitation of mineral phases that were unsaturated in the bulk solution. For one type of mineral solely amended, the $CO_2$ was reduced at the highest of 4.0 mmol for MgO while it was not that much lower for CaO and $SiO_2$ showing 1.1 and 0.3 mmol $CO_2$2, respectively. For two types of minerals simultaneously amended, the $CO_2$ was reduced at the greater extent for both Ca + Mg and Mg + Si showing 2.7 and 2.3 mmol, respectively whereas it was less for Ca + Si at 1.8 mmol. For solidified sludge, the $CO_2$ reduction rate changed depending on the volume of solidified sludge placed in the medium and the input $CO_2$ concentration.. The reduction rate of $CO_2$ was increased with increasing the volume of solidified sludge. Results of XRD analysis indicate that $CaCO_3$ (Calcite) was dominantly formed among others (e.g., Aragonite, Dolomite). SEM analysis showed that the sample with Bacillus pasteurii, could more form minerals rather than control. As demonstrated in this study, $CO_2$ would be effectively sequestered in biomineralization process.

Effect of Co Interlayer on the Interfacial Reliability of SiNx/Co/Cu Thin Film Structure for Advanced Cu Interconnects (미세 Cu 배선 적용을 위한 SiNx/Co/Cu 박막구조에서 Co층이 계면 신뢰성에 미치는 영향 분석)

  • Lee, Hyeonchul;Jeong, Minsu;Kim, Gahui;Son, Kirak;Park, Young-Bae
    • Journal of the Microelectronics and Packaging Society
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    • v.27 no.3
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    • pp.41-47
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    • 2020
  • The effect of Co interlayer on the interfacial reliability of SiNx/Co/Cu thin film structure for advanced Cu interconnects was systematically evaluated by using a double cantilever beam test. The interfacial adhesion energy of the SiNx/Cu thin film structure was 0.90 J/㎡. This value of the SiNx/Co/Cu thin film structure increased to 9.59 J/㎡.Measured interfacial adhesion energy of SiNx/Co/Cu structure was around 10 times higher than SiNx/Cu structure due to CoSi2 reaction layer formation at SiNx/Co interface, which was confirmed by X-ray photoelectron spectroscopy analysis. The interfacial adhesion energy of SiNx/Co/Cu structure decreased sharply after post-annealing at 200℃ for 24 h due to Co oxidation at SiNx/Co interface. Therefore, it is required to control the CoO and Co3O4 formation during the environmental storage of the SiNx/Co/Cu thin film to achieve interfacial reliability for advanced Cu interconnections.

The Effect of Organic Solvents on the Activity for the Synthesis of 12wt% Co-based FT Catalyst (12wt% Co 담지 FT 촉매 제조시 유기용매가 촉매활성에 미치는 영향연구)

  • LEE, JIYUN;HAN, JA-RYOUNG;CHUNG, JONGTAE;BAEK, YOUNGSOON
    • Journal of Hydrogen and New Energy
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    • v.26 no.4
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    • pp.339-346
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    • 2015
  • The synthesis of Fischer-Tropsch (FT) oil is the catalytic hydrogenation of CO to give a range of products, which can be used for the production of high-quality diesel fuel, gasoline and linear chemicals. This studied catalyst was prepared Cobalt-supported alumina and silica by the incipient wet impregnation of the nitrates of cobalt, promoter and organic solvent with supports. Cobalt catalysts were calcined at $350^{\circ}C$ before being loaded into the FT reactors. After the reduction of catalyst has been carried out under $450^{\circ}C$ for 24h, FT reaction of the catalyst has been carried out at GHSV of 4,000/hr under $200^{\circ}C$ and 20atm. From these experimental results, we have obtained the results as following; In case of $SiO_2$ catalysts, the activity of 12wt% $Cobalt-SiO_2$ synthesized by organic solvent was about 2 or 3 times higher than the activity of 12wt% $Cobalt-SiO_2$ catalyst synthesized without organic solvent. In particular, the activity of the $Cobalt-SiO_2$ catalyst prepared in the presence of an organic solvent P was two to three times higher than that of the $Cobalt-SiO_2$ catalyst prepared without the organic solvent. Effect of Cr and Cu metal as a promoter was found little. 200 h long-term activity test was performed with a $Co/SiO_2$ catalyst prepared in the presence of an organic solvent of Glyoxal solution.