• Title/Summary/Keyword: Metal-Al2O3-Si

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Recovery of An, Ag, and Ni from PCB Wastes by CaF2-containing Slag (형우(螢右) 함유(含有) 슬래그 노이(盧理)를 통한 PCB 스크랩으로부터 Au, Ag, Ni의 회수(回收)에 관한 연구(班究))

  • Park, Joo-Hyun
    • Resources Recycling
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    • v.20 no.4
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    • pp.58-64
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    • 2011
  • Recovery of novel metals such as Au, Ag and Ni from wastes PCB was investigated by slag treatments. The CaO-$Al_2O_3$(-$SiO_2$) and CaO-$SiO_2$-$CaF_2$ slags were employed in the present study. The PCB/Cu ratio is recommended to be lower than unity. The use of CaO-$SiO_2$-$CaF_2$ slag provided the more higher yield of Au, Ag and Ni than the CaO-$Al_2O_3$(-$SiO_2$) slag did, which was mainly due to the lower melting point and the viscosity of $CaF_2$-containing slag. The terminal descending velocity of metal droplets in the slag phase increased with decreasing slag viscosity.

Development of $Al_2O_3-SiC-C$ Refractory for Hot Metal Pretreatment (용선예비처리용 $Al_2O_3-SiC-C$계 내화물 개발)

  • 김의호;이석한;이석향;서병길;박정민;이재옥
    • Journal of the Korean Ceramic Society
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    • v.23 no.5
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    • pp.86-92
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    • 1986
  • As there is a growing trend to make high quality steel improving production efficiency and utilizing slag as resources the technologies of hot metal pretreatment have been progressed to meet these demands. Although mill scale $Na_2CO_3$ and CaO used as fluxes proved to be excellent agents then can severely corrode refractories such as chamotte and high alumina for torpedo or open ladle car. Thus it was considered necessary to develop new refractories which can endure suchy conditions. Desulfurization fluxes vastly used in POSCO are $CaCO_3$ and CaO Recent trials have been made by testing phenol resin bonded $Al_2O_3-SiC-C$ bricks in torpedo ladle car for hot metal pretreatment. The results showed that the life of this brick became about 1.2 times longer than that of foreign products. And the crushing strength M.O.R corrosion resistance and oxidation resistance were tested.

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The Effect of SiON Film on the Blistering Phenomenon of Al2O3 Rear Passivation Layer in PERC Solar Cell

  • Jo, Guk-Hyeon;Jang, Hyo-Sik
    • Proceedings of the Korean Vacuum Society Conference
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    • 2014.02a
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    • pp.364.1-364.1
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    • 2014
  • 고효율 태양전지로 가기 위해서는 태양전지의 후면 패시베이션은 중요한 역할을 한다. 후면 패시베이션 막으로 사용되는 $Al_2O_3$ 막은 $Al_2O_3/Si$ 계면에서 높은 화학적 패시베이션과 Negative Fixed Charge를 가지고 있어 적합한 Barrier막으로 여겨진다. 하지만 이후에 전면 Metal paste의 소성 공정에 의해 $800^{\circ}C$이상 온도를 올려주게 됨에 따라 $Al_2O_3$ 막 내부에 결합되어 있던 수소들이 방출되어 blister가 생성되고 막 질은 떨어지게 된다. 우리는 blister가 생성되는 것을 방지하기 위한 방법으로 PECVD 장비로 SiNx를 증착하는 공정 중에 $N_2O$ 가스를 첨가하여 SiON 막을 증착하였다. SiON막은 $N_2O$가스량을 조절하여 막의 특성을 변화시키고 변화에 따라 소성시 막에 미치는 영향에 대하여 조사하였다. 공정을 위해 $156{\times}156mm2$, $200{\mu}m$, $0.5-3.0{\Omega}{\cdot}cm$ and p-type 단결정 실리콘 웨이퍼를 사용하였고, $Al_2O_3$ 막을 올리기 전에 RCA Cleaning 실행하였다. ALD 장비를 통해 $Al_2O_3$ 막을 10nm 증착하였고 RF-PECVD 장비로 SiNx막과 SiON막을 80nm 증착하였다. 소성로에서 $850^{\circ}C$ ($680^{\circ}C$) 5초동안 소성하고 QSSPC를 통해 유효 반송자 수명을 알아보았다.

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Selective Synthesis of Acetonitrile via Direct Amination of Ethanol Over Ni/SiO2-Al2O3 Mixed Oxide Catalysts (Ni/SiO2-Al2O3 복합 산화물 촉매 상에서 에탄올의 직접 아민화 반응에 의한 선택적 아세토니트릴 합성)

  • Kim, Hanna;Shin, Chae-Ho
    • Korean Chemical Engineering Research
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    • v.59 no.2
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    • pp.281-295
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    • 2021
  • In this study, the direct amination of ethanol was performed over impregnated Ni on SiO2-Al2O3 mixed oxide catalysts prepared by varying Si/(Si + Al) molar ratio to 30 mol%. To characterize the physico-chemical properties of the catalysts used, X-ray diffraction (XRD), N2-physisorption, temperature-programmed desorption of iso-propyl alcohol (IPA-TPD), temperature-programmed desorption of ethanol (EtOH-TPD), temperature-programmed reduction with H2 (H2-TPR), H2-chemisorption and transmission electron microscopy (TEM) were used. The acidic property was continuously increased until Si/(Si + Al) = 30 mol% in SiO2-Al2O3 mixed oxides used. The dispersion of Ni metal and surface area, acid characteristics of the supported Ni catalyst have a complex effect on the catalytic reaction activity. The low reduction temperature of nickel oxide and acidic properties were beneficial to the formation of acetonitrile. In terms of conversion of ethanol, Ni/SiO2-Al2O3 catalyst with a molar ratio of 10 mol% Si/(Si+Al) showed the highest activity and a volcanic curve based on it. The tendency of results were consistent in the metal dispersion and catalytic activity.

A study on Brazing Interfacial Properties of $Al_2O_3/Al$ 6061 ($Al_2O_3/Al$ 6061의 접합부 계면특성에 관한 연구)

  • Seo, S.Y.;An, B.G.;Lee, K.Y.
    • Journal of Power System Engineering
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    • v.7 no.3
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    • pp.74-79
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    • 2003
  • Alumina($Al_2O_3$) and Al 6061 were brazed by using Al-12wt% Si filler metal in a high vacuum environment. The interfacial microstructure and mechanical properties of the joints were investigated. The results obtained were as follows. (1) The maximum tensile strength of 54Mpa was acquired at the processing conditions of high vacuum ($3{\times}10^{-6}Torr$), $620^{\circ}C$ and 10min, but this condition will not be used in the industrial area due to high evaporation of Al alloy composition. (2) Reaction products for holding time and brazing temperature worked as stress relieve layer and the fractures after the mechanical properties test were occurred to the ceramic side or reaction layer. (3) The glancing angle X-ray diffraction analysis for the reaction product of $Al_2O_3/Al$ 6061 were processed. the joint strengths were low due to existed $Al_2Si_5\;and\;SiO_2$.

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Fabrication of Aluminum Alloy Composites Reinforced with SiC whisker an $Al_2O_3-SiO_2$ Short Fiber by Squeeze Casting (용탕단조에 의한 $Al_2O_3-SiO_2$ 단섬유 및 SiC whisker강화 알루미늄 합금기 복합재료의 제조)

  • Hong, Sung-Kil;Yun, Jung-Yul;Choi, Jung-Chul
    • Journal of Korea Foundry Society
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    • v.17 no.1
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    • pp.28-35
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    • 1997
  • SiC whisker and $Al_2O_3-SiO_2$ short fiber reinforced AC8A, AC8B and AC8B(J) marix composites were fabricated by squeeze casting method. Preform deformation, change of reinforcement volumefraction and formation of macro-segregation in two composites were investigated by using micro Vickers hardness test, analysis of macro and micro structures with OM, SEM and EDAX. $Al_2O_3-SiO_2$ short fiber preform manufactured with 5% $SiO_2$ binder in this study was considerably deformed and cracked, nevertheless, the short fibers were distributed homogeneously in the composites. In SiC whisker reinforced composites, on the other hand, preform deforming and cracking were not occurred, however, macro segregation zone formed along the infiltration routes by interface reaction during infiltration of molten metal into the preform was observed at center-low area in the composites. The decrease of hardness in the macro segregation zone resulted from the depletion of Si and Mg atoms.

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Thickness dependency of MAHONOS ($Metal/Al_2O_3/HfO_2/SiO_2/Si_3N_4/SiO_2/Si$) charge trap flash memory

  • O, Se-Man;Yu, Hui-Uk;Kim, Min-Su;Lee, Yeong-Hui;Jeong, Hong-Bae;Jo, Won-Ju
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2009.11a
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    • pp.34-34
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    • 2009
  • The electrical characteristics of tunnel barrier engineered charge trap flash (TBE-CTF) memory with $SiO_2/Si_3N_4/SiO_2/Si$ engineered tunnel barrier, $HfO_2$ charge trap layer and $Al_2O_3$ blocking oxide layer (MAHONOS) were investigated. The energy bad diagram was designed by using the quantum-mechanical tunnel model (QM) and then the CTF memory devices were fabricated. As a result, the best thickness combination of MAHONOS is confirmed. Moreover, not enhanced P/E speed (Program: about $10^6$ times) (Erase: about $10^4$ times) but also enhanced retention and endurance characteristics are represented.

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Preparation of Ultra-Low Thermal Expansion L$i_2$O-A$l_2$$O_3$-Si$O_2$ Glass-Ceramics by Sol-gel Technique (졸-겔 방법에 의한 $Li_2O-Al_2O_3-SiO_2$계 저열팽상성 결정화유리의 제조)

  • Yang, Jung-Sik;Kim, Jong-Beom;Yang, Jung-Sik
    • Korean Journal of Materials Research
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    • v.3 no.3
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    • pp.207-214
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    • 1993
  • Glass-ceramic monoliths with an ultra-low thermal expansion coefficient have been synthesized by the sol-gel technique using metal alkoxides as starting materials and dimethyl formamide as a drying control chemical additive. The ternary gels: $Li_2O\cdot Al_2O_3\cdot 2, 4 or $6SiO_2$ were obtained by hydrolysis and polycondensation reactions of metal alkoxides of silicon, aluminum and lithium. To produce cylindrical crack-free gel monoliths, excess water was used to the starting solutions and drying rates were controlled precisely to prevent cracking. In conversion process ,${\beta}$-eucryptite, $Li_2O\cdot Al_2O_3\cdot 3SiO_2$ and P-spodumene with ,${\beta}$-quartz solid solution phase were obtained by heating at the range of 750 ~$1000^{\circ}C$. Above $800^{\circ}C$, the ,${\beta}$-spodumene phase increased while ,${\beta}$-eucryptite phase decreased. The thermal expansion coefficient of the crystallized specimens were -15~ $+5{\times}{10^{-7}}/{\circ}C$ over the temperature range from room temperature to $600^{\circ}C$.

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Fracture and Residual Stresses in $Metal/Al_2O_3-SiO_2$ System

  • Soh, D.;Korobova, N.
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2003.11a
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    • pp.308-312
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    • 2003
  • The packaging of the integrated circuits requires knowledge of ceramics and metals to accommodate the fabrication of modules that are used to construct subsystems and entire systems from extremely small components. Composite ceramics ($Al_2O_3-SiO_2$) were tested for substrates. A stress analysis was conducted for a linear work-hardening metal cylinder embedded in an infinite ceramic matrix. The bond between the metal and ceramic was established at high temperature and stresses developed during cooling to room temperature. The calculations showed that the stresses depend on the mismatch in thermal expansion, the elastic properties, and the yield strength and work hardening rate of the metal. Experimental measurements of the surface stresses have also been made on a $Cu/Al_2O_3-SiO_2$ ceramic system, using an indentation technique. A comparison revealed that the calculated stresses were appreciably larger than the measured surface stresses, indicating an important difference between the bulk and surface residual stresses. However, it was also shown that porosity in the metal could plastically expand and permit substantial dilatational relaxation of the residual stresses. Conversely it was noted that pore clusters were capable of initiating ductile rupture, by means of a plastic instability, in the presence of appreciable tri-axiality. The role of ceramics for packaging of microelectronics will continue to be extremely challenging.

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Plasma-sprayed Coatings of Aluminium Oxide and Mulite

  • Soh, Dea-Wha;Korobova, N.
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2003.11a
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    • pp.336-339
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    • 2003
  • The present report is the investigation of the effects of the HIP treatment on plasma-sprayed ceramic coating of $Al_2O_3$, $Al_2O_3-SiO_2$ on the metal substrate. These effects were characterized by phase identification, Vickers hardness measurement, and tensile test before and after HIPing.

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