• Title/Summary/Keyword: aluminum-silicon system

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Synthesis of $\beta$다-Sialon with Various Compositions from Kaolin (카올린으로부터 조성이 다른$\beta$다-Sialon의 합성)

  • 최상욱;서규식;이종진
    • Journal of the Korean Ceramic Society
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    • v.23 no.5
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    • pp.17-24
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    • 1986
  • β'-Sialon with different compositions was synthesized by the carbothermal reduction-nitridation of compacts containing kaolin graphite and silicon or aluminum at temperature of 1300-1450℃ under flowing gas of 90% N2-10% H2 or 20hrs. Quantitative analysis of minerals which were formed in the specimens was carried out by using the calibration curve which has been prepared from X-ray diffraction patterns. The obtained results were as follows : 1. In the formation of β'-Sialon by carbothermal reduction-nutridation of Si-Al-O-C system mixtures at 1400℃ for 20hrs. (2) β'-Sialon as a major mineral and α-Al2O3 as a minor mineral were identified in the specimen which was prepared of kaolin and graphite. (3)α-Al2O3 and 15R as a minor minerals were measured in the specimen which was prepared of kaolin aluminum and graphite. (4) AlN instead of α-Al2O3 and 15R was formed in the compacts that excess graphite(=35 wt%) was added to the mixture of kaolin and aluminium. 2. As the reaction time and temperature were increased the formation of β'-Sialon was increased whereas the phases of mllite SiC and Si2ON2 were decreased gradually.

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Effect of 3C-SiC buffer layer on the characteristics of AlN films supttered on Si Substrates (3C-SiC 버퍼층이 Si 기판위에 스퍼터링된 AlN 막의 특성에 미치는 영향)

  • Ryu, Kyeong-Il;Chung, Gwiy-Sang
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2009.04b
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    • pp.3-6
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    • 2009
  • Aluminum nitride (AIN) thin films were deposited on a polycrystalline 3C-SiC intermediate layer by a pulsed reactive magnetron sputtering system. Characteristics of the AIN/SiC heterostructures were investigated by field emission scanning electron microscopy (FE-SEM), atomic force microscopy (AFM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FT-IR). The columnar structure of AIN thin films was observed by FE-SEM. The surface roughness of AlN films on the 3C-SiC buffer layer was measured using AFM. The XRD pattern of AlN films on SiC buffer layers was highly oriented at (002). Full width at half maximum (FWHM) of the rocking curve near (002) reflections was $1.3^{\circ}$. The infrared absorbance spectrum indicated that the residual stress of AIN thin films grown on SiC buffer layers was nearly negligible. The 3C-SiC intermediate layers are promising for the realization of nitride based electronic and mechanical devices.

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Effect on the Residual Stress of Cure Profiles, Fillers and Mold Constraints in an Epoxy System

  • Moon, Chang-Kwon;Nam, Ki-Woo
    • Journal of Ocean Engineering and Technology
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    • v.23 no.4
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    • pp.1-5
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    • 2009
  • A dilatometer was used to investigate the effect of cure conditions, mold types and the presence of filler in an epoxy system. These studies showed shrinkage in the cured epoxy when heating it through the glass transition temperature region. The magnitude of the shrinkage, related to stress build up in the epoxy during curing, was influenced by the processing conditions, filler presence and the nature of the mold used to contain the resin. Cure and cyclic cure at a lower temperature, prior to a post cure, decreased the magnitude of observed shrinkage. Cure shrinkage decreased with the number of cyclic cures. Post cured samples outside the mold led to less shrinkage compared with samples in the mold. Sample cured in a silicon mold represented less shrinkage than sample cured in an aluminum mold. Sample containing kaolin filler showed less shrinkage than unfilled sample.

A Study on the Zeta Potential Measurement and the Stability Analysis of Nano Fluids using a Particle Image Processing System (입자 영상 처리 시스템을 이용한 콜로이드 입자의 제타포텐셜 측정 및 나노유체 분산 특성 연구)

  • Lee, J.K.;Kim, S.C.;Kim, H.J.;Lee, C.G.;Ju, C.H.;Lee, L.C.
    • Journal of ILASS-Korea
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    • v.8 no.1
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    • pp.16-22
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    • 2003
  • Zeta potential measurements of colloid particles suspended in a liquid are performed by a Zeta Meter developed. There are many applications of colloid stability in spray technology, paints, wastewater treatment, and pharmaceuticalse. Zeta potentials of charged particles are obtained by measuring the electrophoretic velocities of the particles using video enhanced microscopy and image analysis program. The values of zeta potential of polystyrene latex(PSL), $silica(SiO_2)$M, polyvinylidence difluoride(PVDF), silicon nitride, and alumina particles in deionized (DI) water were measured to be -40.5, -31.9, -25.2, -15.1 and -10.1mV, respectively. The particles having high zeta potential less than -20 mV are stable in DI water, because the double layers of them have strong repulsive forces mutually, and the particles having low zeta potential over -20mV are unstable due to Van Der Waals forces. Silica(>20nm), PSL, aluminum and PVDF particles were found to be stable that would remain separate and well disperse, while silicon nitride and alumina particles were found to be unstable that would gradually agglomerate in DI water.

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Design Optimization of a Type-I Heterojunction Tunneling Field-Effect Transistor (I-HTFET) for High Performance Logic Technology

  • Cho, Seong-Jae;Sun, Min-Chul;Kim, Ga-Ram;Kamins, Theodore I.;Park, Byung-Gook;Harris, James S. Jr.
    • JSTS:Journal of Semiconductor Technology and Science
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    • v.11 no.3
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    • pp.182-189
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    • 2011
  • In this work, a tunneling field-effect transistor (TFET) based on heterojunctions of compound and Group IV semiconductors is introduced and simulated. TFETs based on either silicon or compound semiconductors have been intensively researched due to their merits of robustness against short channel effects (SCEs) and excellent subthreshold swing (SS) characteristics. However, silicon TFETs have the drawback of low on-current and compound ones are difficult to integrate with silicon CMOS circuits. In order to combine the high tunneling efficiency of narrow bandgap material TFETs and the high mobility of III-V TFETs, a Type-I heterojunction tunneling field-effect transistor (I-HTFET) adopting $Ge-Al_xGa_{1-x}As-Ge$ system has been optimized by simulation in terms of aluminum (Al) composition. To maximize device performance, we considered a nanowire structure, and it was shown that high performance (HP) logic technology can be achieved by the proposed device. The optimum Al composition turned out to be around 20% (x=0.2).

Effects of Iron and Silicon Additions on the Microstructures and Mechanical Properties of Aluminium Bronze (알루미늄 청동의 미세조직과 기계적 성질에 미치는 Fe 및 Si 첨가의 영향)

  • Kim, Jee-Hwan;Kim, Ji-Tae;Kim, Jin-Han;Park, Heung-Il;Kim, Sung-Gyoo
    • Journal of Korea Foundry Society
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    • v.36 no.6
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    • pp.202-207
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    • 2016
  • The effects of Fe and Si additions on the microstructures and mechanical properties of aluminum bronze have been investigated. In a bar-type specimen cast in a die mold, the addition of Fe promoted the dendritic solidification of the ${\alpha}$ phase. The hardness values increased slightly in the Fe-added specimen with heat treatment, while these values was increased significantly in the specimens with Si or with combined additions of Fe and Si. When a centrifugal casting bush with combined addition of Fe and Si was heat treated, the FeSi compound within the matrix was finely dispersed, and was observed to be the origin of cup-cone type conical dimple failure in the tensile fracture surface. The mechanical properties of the heat treated centrifugal casting bushes, whose nominal alloy compositions were (Cu-7.0Al-0.8Fe-3.0Si)wt%, exhibited tensile strength of $703-781N/mm^2$, elongation of 6.6-11.7% and hardness of Hv 222.6-249.2. These high values of strength and elongation were attributed to the strengthening of the matrix due to the combined addition of Fe and Si, and to precipitation of fine the FeSi compound.

Development of a Test Strip Reader for a Lateral Flow Membrane-based Immunochromatographic Assay

  • Park, Je-Kyun;Kim, Suhyeon
    • Biotechnology and Bioprocess Engineering:BBE
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    • v.9 no.2
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    • pp.127-131
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    • 2004
  • A low-cost, simple strip reader system using a linear movement mechanism of CD-ROM deck has been developed to characterize a lateral flow membrane-based immunochromatographic assay. The test strip reader was assembled by a CD-ROM deck and home-made optical head especially designed for immunoassays. The optical head for detecting reflected light from the test strip surface consists of green light-emitting diode, large area silicon photodiode, and anodized aluminum mounting block providing a slit structure for cutting light from the LED. The stepping motor of the deck was operated in the full step mode, whose distance of each reading point is about 0.15mm. The performance of the strip reader was tested by analysis of HBV(hepatitis B virus) antigen test kit. This strip reader can be useful for inexpensive, disposable, and membrane-based assays that provide visual evidence of the presence of an analyte in a liquid sample.

SEM/EDX Analysis on the Composition and Surface Defect in a Pin Bushing Bearing for an Automotive Engine (자동차 엔진용 핀부싱 베어링의 SEM/EDX 이용 성분.결함분석에 관한 연구)

  • Kim, Chung-Kyun
    • Tribology and Lubricants
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    • v.23 no.5
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    • pp.195-200
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    • 2007
  • This paper presents the friction induced scuffing and wear defects analysis of a pin bushing bearing based on the chemical composition using a scanning microscopy (SEM) and an energy dispersive X-ray analyzer (EDX). The SEM/EDX system, which may provide good information on the surface thermal defects and chemical compositions, provides impurities such as an aluminum, a silicon, a ferrous component and an oxygen, especially. The EDX measured results show that the oxygen may reduce the strength and a hardness of a pin busing, which may lead to a scuffing and a seizure on the rubbing contact surface. The current technology fabricated by a sintering for a pin bushing bearing should be modified or changed to reduce the oxygen composition and the impurities in pin bushing materials.

Numerical Analysis of Thermal Flow for Materials of Combined Weapon System in Large Environmental Tester (대형 환경시험조 내의 복합무기체계 재료에 대한 열유동 수치해석)

  • Kim, Sung-Dae;Ryoo, Seong-Ryoul;Baek, Sang-Hwa;Lee, Jeong-Yong;Park, So-Jin;Kim, Chul-Ju;Ko, Han-Seo
    • Proceedings of the KSME Conference
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    • 2007.05b
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    • pp.3144-3149
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    • 2007
  • A numerical analysis for temperature distribution of four different materials such as iron, silicon, aluminum and PVC has been performed in this study to predict thermal behaviors of combined weapon systems in a large environmental tester. Thus, experimental conditions have been proposed using a calculating software (SolidWorks 2007 COSMOS FloWorks) to prepare for field tests and analyze heat flow inside the environmental tester and temperature distributions of materials. The boundary conditions of the analysis are composed of inlet and outlet conditions of the environmental tester with different pressures and the limit of low temperature of -30$^{\circ}C$. The soaking time of the system in the environmental tester has been calculated by this commercial program in this study to carry out the experiment.

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A STUDY ON THE GLOSS AND ROUGHNESS OF THE COMPOSITE RESIN (복합레진의 광택 및 표면조도에 관한 연구)

  • Cho, Seung-Joo;Lee, Myung-Jong
    • Restorative Dentistry and Endodontics
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    • v.15 no.1
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    • pp.67-80
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    • 1990
  • This study was performed for elucidating the effects on surface polishing of composite resins. In this study, Silux(microfilled), Graft(hybrid), Bisfil- I (hybrid posterior) and Hi-pol(conventional) were used. Sixty specimens were made with 4 brands of composite resins and Optilux system in $2.0{\times}1.3{\times}1.0cm$ resin block which has a cavity with 0.5cm diameter and 0.5cm depth. Polishing was done with #600 sand paper and Soflex, Super-snap, Micron finishing system, or Composite polishing kit. Final polished surfaces were measured by roughness tester(Kasaka Lab. Ltd., Japan) and image analyser(Omnimet Image Analyser, Buehler, USA). The results were as follows, 1. The celluloid strip produced the smoothest surfaces. 2. Light curing microfilled composite resin, Silux, had smoother surface than any others. 3. The surfaces polished by Soflex were smoothest. 4. Aluminum oxide disk, Soflex and Super-Snap, made smoother surface than diamond bur, M.F.S., or silicon point, Composite polishing kit. 5. The roughness values of surface polished by M.F.S. composed of diamond burs, were less than those of Composite polishing kit made from silicone points.

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