• Title/Summary/Keyword: Compound Surface

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The Characteristics of Compound Layers Formed during Plasma Nitrocarburising in Pure Iron (플라즈마 침질탄화처리된 순철의 화합물층 특성)

  • Cho, H.S.;Lee, S.Y.;Bell, T.
    • Journal of the Korean Society for Heat Treatment
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    • v.13 no.3
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    • pp.143-150
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    • 2000
  • Ferritic plasma nitrocarburising was performed on pure iron using a modified DC plasma unit. This investigation was carried out with various gas compositions which consisted of nitrogen, hydrogen and carbon monoxide gases, and various gas pressures for 3 hours at $570^{\circ}C$. After treatment, the different cooling rates(slow cooling and fast cooling) were used to investigate its effect on the structure of the compound layer. The ${\varepsilon}$ phase occupied the outer part of the compound layer and ${\gamma}^{\prime}$ phase existed between the ${\varepsilon}$ phase and the diffusion zone. The gas composition of the atmosphere influenced the constitution of the compound layer produced, i.e. high nitrogen contents were essential for the production of ${\varepsilon}$ phase compound layer. It was found that with increasing carbon content in the gas mixture the compound layer thickness increased up to 10%. In the gas pressure around 3 mbar, the compound layer characteristics were slightly effected by gas pressure. However, in the low gas pressure and high gas pressure, the compound layer characteristics were significantly changed. The constitution of the compound layer was altered by varying the cooling rate. A large amount of ${\gamma}^{\prime}$ phase was transformed from the ${\varepsilon}$ phase during slow cooling.

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Effect of the Low Profile Agent and Release Agent on the Surface Morphology and Property of Bulk Mold Compound (저수축제 및 이형제가 벌크몰드컴파운드의 표면형태 및 물성에 미치는 영향)

  • Kim, Sung-Ryong;Kwon, Ki-Joon
    • Journal of Adhesion and Interface
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    • v.12 no.4
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    • pp.144-150
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    • 2011
  • The effect of low profile agent and release agent on the surface and mechanical properties of bulk mold compound were investigated. Atomic content and contact angle of surface were characterized using X-ray photoelectron spectroscopy and contact anglemeter. Surface morphology and surface roughness were obtained using field emission scanning electron microscope and atomic force microscope, respectively. As increasing the low profile agent from 0 to 9.2 wt%, the volume shrinkage and surface roughness decreased from 0.35% to 0.05%, and from $0.27{\mu}m$ to $0.12{\mu}m$, respectively. The increase of release agent from 1.8 wt% to 3.6 wt% resulted in the migration of release agent to sample surface and it increased the surface roughness. The flexural strength and impact strength were decreased approximately 30% as the low profile agent increasing from 5.0 wt% to 9.0 wt%.

Effect of Surface Treatment of Porcelain on Tensile Bond Strength (도재의 표면처리가 인장접착강도에 미치는 영향)

  • KIM, Shin-Geun;SUNG, Jae-Hyun
    • The korean journal of orthodontics
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    • v.26 no.3
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    • pp.301-307
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    • 1996
  • The purpose of this study was to evaluate the effect of surface treatment of porcelain on tensile bond strength. To accomplish this purpose, this study was carried out with 120 samples which were divided into 12 groups with each 10 samples, and the first group was not surface treated, groups 2 through 5 underwent single surface treatment, and groups 6 through 12 underwent compound surface treatment. The results were as follows : 1. In statistic, all the single surface-treated groups showed higher tensile bond strength than the non surface-treated group and the sandblasted group showed the highest tensile bond strength as $10.34{\pm}2.50MPa$. 2. All the compound surface-treated groups showed no noticeable difference in the tensile bond strength(9-11.5MPa). 3. In statistic, no significant difference was found between the sandblasted group and the compound surface-treated groups. 4. There was no fracture of porcelain while testing in this study. Above study demonstrated that compound surface treatment or sandblasing, if used single surface treatment, should be employed to guarantee successful clinical application.

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Behavior of Graphite and Formation of Intermetallic Compound Layer in Hot Dip Aluminizing of Cast Iron (주철 - 알루미늄 합금의 Hot Dip Aluminizing시 흑연 및 금속간화합물 층의 형성 거동)

  • Han, Kwang-Sic;Kang, Yong-Joo;Kang, Mun-Seok;Kang, Sung-Min;Kim, Jin-Su;Son, Kwang-Suk;Kim, Dong-Gyu
    • Journal of Korea Foundry Society
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    • v.31 no.2
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    • pp.66-70
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    • 2011
  • Hot dip aluminizing (HDA) is widely used in industry for improving corrosion resistance of material. The formation of intermetallic compound layers during the contact between dissimilar materials at high temperature is common phenomenon. Generally, intermetallic compound layers of $Fe_2Al_5$ and $FeAl_3$ are formed at the Al alloy and Fe substrate interface. In case of cast iron, high contact angle of graphite existed in the matrix inhibits the formation of intermetallic compound layer, which carry with it the disadvantage of a reduced reaction area and mechanical properties. In present work, the process for the removal of graphite existed on the surface of specimen has been investigated. And also HDA was proceeded at $800^{\circ}C$ for 3 minutes in aluminum alloy melt. The efficiency of graphite removal was increased with the reduction of particle size in sanding process. Graphite appears to be present both in the region of melting followed by re-solidification and in the intermetallic compound layer, which could be attributed to the fact that the surface of cast iron is melted down by the formation of low melting point phase with the diffusion of Al and Si to the cast iron. Intermetallic compound layer consisted of $Fe(Al,Si)_3$ and $Fe_2Al_5Si$, the layer formed at cast iron side contained lower amount of Si.

Effect of Complex Agent NH3 Concentration on the Chemically Deposited Zn Compound Thin Film on the $Cu(In,Ga)Se_2$

  • Shin, Dong-Hyeop;Larina, Liudmila;Yun, Jae-Ho;Ahn, Byung-Tae;Park, Hi-Sun
    • Proceedings of the Materials Research Society of Korea Conference
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    • 2010.05a
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    • pp.35.1-35.1
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    • 2010
  • The Cu(In,Ga)Se2(CIGS) thin film solar cells have been achieved until almost 20% efficiency by NREL. These solar cells include chemically deposited CdS as buffer layer between CIGS absorber layer and ZnO window layer. Although CIGS solar cells with CdS buffer layer show excellent performance, many groups made hard efforts to overcome its disadvantages in terms of high absorption of short wavelength, Cd hazardous element. Among Cd-free candidate materials, the CIGS thin film solar cells with Zn compound buffer layer seem to be promising with 15.2%(module by showa shell K.K.), 18.6%(small area by NREL). However, few groups were successful to report high-efficiency CIGS solar cells with Zn compound buffer layer, compared to be known how to fabricate these solar cells. Each group's chemical bah deposition (CBD) condition is seriously different. It may mean that it is not fully understood to grow high quality Zn compound thin film on the CIGS using CBD. In this study, we focused to clarify growth mechanism of chemically deposited Zn compound thin film on the CIGS, especially. Additionally, we tried to characterize junction properties with unfavorable issues, that is, slow growth rate, imperfect film coverage and minimize these issues. Early works reported that film deposition rate increased with reagent concentration and film covered whole rough CIGS surface. But they did not mention well how film growth of zinc compound evolves homogeneously or heterogeneously and what kinds of defects exist within film that can cause low solar performance. We observed sufficient correlation between growth quality and concentration of NH3 as complex agent. When NH3 concentration increased, thickness of zinc compound increased with dominant heterogeneous growth for high quality film. But the large amounts of NH3 in the solution made many particles of zinc hydroxide due to hydroxide ions. The zinc hydroxides bonded weakly to the CIGS surface have been removed at rinsing after CBD.

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Influence of Pulse Parameters on the Plasma Nitriding of SCM435 Steels (SCM 435 강의 플라즈마 질화처리시 펄스 인자의 영향)

  • Song, Dong-Won;Lee, In-Seop
    • Korean Journal of Materials Research
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    • v.11 no.12
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    • pp.1063-1067
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    • 2001
  • The effect of the pulse parameters(pulse ratio and frequency) on the characteristics of the nitrided layer in the pulsed plasma nitrified SCM435 Steels was investigated. Material properties of the nitrided layer were analysed by employing optical microscope, scanning electron microscope(SEM), X-ray diffractometer(XRD) and micro-Vickers hardness tester. It was found that both the compound layer thickness and the surface hardness decreased with decreasing of pulse ratios. At high pulse ratio, the compound layer thickness and the surface hardness were rapidly decreased with decreasing frequency compared to lower pulse ratios.

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Role of Energy and Composition of Film-Forming Species in Formation of Composition and Structure of Compound Films

  • Shaginyan, L.R.
    • Journal of the Korean institute of surface engineering
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    • v.34 no.5
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    • pp.455-464
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    • 2001
  • Effect of bombardment of the growing film by energetic particles on its properties is know over many years and is widely used for modification of the film properties. Despite of this there are no final answers on such questions as: what is the mechanism of compositional changes that take place for some compound films deposited under the ion bombardment, how the ion bombardment influences the epitaxial growth, what mechanisms govern the growth of the film on its early stages during deposition under the ion bombardment. The role of composition of film-forming species in formation of film structure is barely investigated or even not investigated at all. Experimental evidence and discussion of the influence of ion bombardment and composition of film-forming species on structure and composition of compound films are briefly considered in the review.

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Reverse Engineering of Compound Surfaces on the Machine Tool using a Vision Probe (비전 프로브를 이용한 기상에서의 복합곡면의 역공학)

  • 김경진;윤길상;초명우;권혁동;서태일
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2002.05a
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    • pp.287-292
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    • 2002
  • This paper presents a reverse engineering method for compound surfaces using vision system. A CNC machining center is used as a measuring station, which is equipped with slit beam generator and vision probe. Since obtained data using slit beam or laser scanner may have much data loss along the edge of compound surfaces, an algorithm is presented in this study to recover missing geometric data at such region. First, b-spline interpolation is applied to extract edge information of the surface, and as a next step, b-spline approximation is applied to recover the missing geometric data. Finally, b-spline skinning method is applied to regenerate the surface information. Appropriate simulation and experimental works are preformed to very the effectiveness of the proposed methods.

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Fine Structure of Compound Eye Surface in Korean Asilinae (Asilidae, Diptera, Insecta) (한국산(韓國産) 파리매아과(亞科)(파리매과(科), 파리목(目), 곤충강(綱))의 복안(複眼)표면 미세구조)

  • Lee, Ok Jin
    • Journal of Korean Ophthalmic Optics Society
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    • v.5 no.2
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    • pp.211-219
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    • 2000
  • The fine structure on the compound eye surface of 6 species belong to 6 genera of Asilinae in Korea was morphologically studied with a scanning electron microscope and image analyser. The compound eye was divided into 3 parts(medial, middle, and lateral) according to a difference in the diameter of a facet which was various form. The fine structure of a facet in Trichomachimus scutellaris(Coquillett) was valuable in taxonomy because it was differ from each species in Asilinae.

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A Study on the of Intermetallic compound and shear strength of Sn3.5Ag0.7Cu ball with interface position (Sn3.5Ag0.7Cu 솔더의 계면위치에 따른 금속간 화합물과 강도 연구)

  • 신규식;박지호;정재필
    • Journal of the Korean institute of surface engineering
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    • v.35 no.1
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    • pp.47-52
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    • 2002
  • Intermetallic compound on the soldered interface plays important role on the bondability and mechanical properties of soldered joint. The formation of intermetallic compounds are influenced by many factors such as temperature, holding time, base metals and so on. On this study the effect of number of reflow times on the intermetallic growth was investigated. For the experimental materials, Sn-3.5Ag-0.7Cu solder ball of 0.3mm diameter and RMA-type flux were used. Thickness of intermetallic compound of solder ball by 2nd reflow showed nearly 60% higher than that of 1st reflow, and shear strength showed 10% higher value. Thickness and shear strength according to the position of interface such as upper side or lower side between two substrates were also investigated.