• Title/Summary/Keyword: micro coatings

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Material Properties of Thick Aluminum Coating Made by Cold Gas Dynamic Spray Deposition (초음속 저온분사법에 의해 적층된 알루미늄 층의 재료 물성)

  • Lee, Jae-Chul;Ahn, Sung-Hoon
    • Journal of the Korean Society for Precision Engineering
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    • v.23 no.10
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    • pp.88-95
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    • 2006
  • Cold gas dynamic spray is a relatively new coating process by which coatings can be produced without significant heating during the process. Cold-spray uses supersonic gas flow to carry metallic powders to the substrate. Its low process temperature can minimize thermal stress and also reduce the deformation of the substrate. Most researches on cold-spray have focused on micro scale coating, but in this study macro scale deposition was conducted. Properties of aluminum layer by cold-spray deposition such as coefficient of thermal expansion (CTE), modulus of elasticity. hardness, and electric conductivity were measured. The results showed that properties of aluminum layer by cold-spray deposition were different from properties of pure aluminum and aluminum alloy.

Effect of Sealing Process on the Tribological Behavior of the Plasma Spray Zirconia Based Coatings (지르코니아 충전이 지르코니아계 용사코팅층의 마모마찰에 미치는 영향)

  • 신종한;임대순;안효석
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • 1998.10a
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    • pp.265-271
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    • 1998
  • High temperature wear behavior of plasma sprayed zirconia based coating sealing with zirconia sol were investigated for high temperature wear resistance application. The zirconia powders containing 2.5, 5.0, 7.5, 10.0 mol% of MoS$_2$, $Fe_2O_3$ for plasma spray were made by spray drying method. As-sprayed coating was sealed by zirconia-sol to fill up the pore and crack in coating. wear test were performed at temperature ranges from room temperature to 600$\circ$C. The microstructural changes of before and after sealing process were examined by SEM, XRD and EPMA. After sealing process, the porosity was decreased and micro-hardness was increased. The wear properties of coating after sealing process were improved by sealing of pores and cracks. The behavior of wear amount and coefficient of friction were same tendency to before sealing process.

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Cutting performance of Cr-Al-Si-N micro end-mill tool deposited by a hybrid coatings (하이브리드 코팅에 의한 Cr-Al-Si-N 마이크로 엔드밀공구의 가공성능)

  • Gang, Myeong-Chang;Sin, Seok-Hun;Kim, Min-Uk;Tak, Hyeon-Seok;Kim, Gwang-Ho;Kim, Jeong-Seok
    • Proceedings of the Korean Institute of Surface Engineering Conference
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    • 2009.05a
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    • pp.211-211
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    • 2009
  • 높은 이온화율과 복잡한 형상의 모재에도 표면 도포성 및 균일성을 나타내는 아크이온플래이팅 기술과 비전도성 세라믹 타겟물질에 적용가능한 스퍼터링 기술이 결합된 하이브리드 코팅 시스템(Hybrid coating system)을 이용하였다. 그리고 Cr-Al-N과 Cr-Si-N 코팅막의 강화 기구를 복합시킨 새로운 개념의 Cr-Al-Si-N 코팅막을 초경(WC-Co)시험편에 증착하여 Si 첨가량에 따른 미세구조의 미세경도 특성을 파악하였다. 공구성능 평가는 고속가공조건하에 마이크로 밀링기에서 무코팅(초경공구), Cr-Al-Si-N (Si : 0, 4.5, 8.7, 16 at.%) 코팅 마이크로엔드밀에 대하여 공구마멸에 대한 공구수명을 비교, 평가하였다.

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Bioinspired Nanoengineering of Multifunctional Superhydrophobic Surfaces

  • Choi, Chang-Hwan
    • Proceedings of the Korean Institute of Surface Engineering Conference
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    • 2015.11a
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    • pp.102-133
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    • 2015
  • Nature, such as plants, insects, and marine animals, uses micro/nano-textured surfaces in their components (e.g., leaves, wings, eyes, legs, and skins) for multiple purposes, such as water-repellency, anti-adhesiveness, and self-cleanness. Such multifunctional surface properties are attributed to three-dimensional surface structures with modulated surface wettability. Especially, hydrophobic surface structures create a composite interface with liquid by retaining air between the structures, minimizing the contact area with liquid. Such non-wetting surface property, so-called superhydrophobicity, can offer numerous application potentials, such as hydrodynamic drag reduction, anti-biofouling, anti-corrosion, anti-fogging, anti-frosting, and anti-icing. Over the last couple of decades, we have witnessed a significant advancement in the understanding of surface superhydrophobicity as well as the design, fabrication, and applications of superhydrophobic coatings/surfaces/materials. In this talk, the designs, fabrications, and applications of superhydrophobic surfaces for multifunctionalities will be presented, including hydrodynamic friction reduction, anti-biofouling, anti-corrosion, and anti-icing.

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Micro structure and mechanical properties of CrZrON coatings Synthesized by Cr-Zr Segment Target and unbalanced magnetron sputtering (Cr-Zr Segmet target과 unbalanced magnetron sputtering을 이용하여 합성한 CrZrON 박막의 미세구조 와 기계적 특성)

  • Kim, Dong-Jun;Ra, Jeong-Hyeon;Kim, Seong-Min;Lee, Sang-Yul
    • Proceedings of the Korean Institute of Surface Engineering Conference
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    • 2013.05a
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    • pp.176-176
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    • 2013
  • CrZrN 3원계 박막은 상온에서 매우 우수한 기계적 특성을 나타내지만, $500^{\circ}C$ 이상의 고온에서는 Zr의 산화로 인하여 기계적 특성이 저하되게 된다. 따라서 본 연구에서는 CrZrN 박막의 고온 특성을 개선하기 위해서 내산화성이 향상에 영향을 미치는 표면 산화물을 만들기 위해 산소 원소를 첨가하여 CrZrON 4원계 oxynitride 박막을 segment target을 이용해 합성하였고, 박막의 미세구조를 분석하였다.

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Pd-based metallic membranes for hydrogen separation and production

  • Tosti, Silvano;Basile, Angelo
    • Proceedings of the Membrane Society of Korea Conference
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    • 2003.07a
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    • pp.25-28
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    • 2003
  • Low cost composite metallic membranes for the hydrogen separation and production have been prepared by using thin Pd-Ag foils reinforced by metallic (stainless steel and nickel) structures. Especially, “supported membranes” have been obtained by a diffusion welding procedure in which Pd-Ag thin foils have been joined with perforated metals (nickel) and expanded metals (stainless steel): in these membranes the thin palladium foil assures both the high hydrogen permeability and the perm-selectivity while the metallic support provides the mechanical strength. A second studied method of producing "laminated membranes" consists of coating non-noble metal sheets with very thin palladium layers by diffusion welding and cold-rolling. Palladium thin coatings over these metals reduce the activation energy of the hydrogen adsorption process and make them permeable to the hydrogen. In this case, the dense non-noble metal has been used as a support structure of the thin Pd-Ag layers coated over its surfaces: a proper thickness of the metal assures the mechanical strength, the absence of defects (cracks, micro-holes) and the complete hydrogen selectivity of the membrane. membrane.

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Application and Processes for Sputtered ITO Films (스퍼터 ITO박막의 제조 공정 이해 및 활용)

  • Song, Pung-Keun
    • Journal of Surface Science and Engineering
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    • v.50 no.2
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    • pp.55-71
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    • 2017
  • Transparent Conductive Oxide (TCO), especially Indium Tin Oxide (ITO) films are almost prepared by DC magnetron sputtering because of the advantage of obtaining homogeneous large area coatings with high reproducibility. The purpose of this report is describe a detailed investigation of key factors dominating electrical and structural properties of sputtered ITO films. It was confirmed that crystallinity and electrical properties of ITO films were strongly depend on the sputtering pressure and kinetic energy of sputtered particles which are expected to have a close relation with the transport processes between target and substrate. And also, nodule formation on the ITO target was suppressed by both $CaCO_3$ addition and decreasing micro-pore in the target. On the other hand, we focused on the characteristics of amorphous TCO film to use as transparent electrode for various applications. To realize high thermoelectric performance, it was tried to control both high electrical conductivity and low thermal conductivity for the amorphous IZO:Sn films.

TiN coatings by HCD plasma enhanced reactive ion plating method (HCD플라즈마를 이용한 반응성 이온플레이팅법에 의한 TiN 코팅)

  • 서용운;황기웅
    • Journal of Surface Science and Engineering
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    • v.25 no.3
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    • pp.133-143
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    • 1992
  • Titanium nitride(TiN) films have been prepared by HCD plasma enhanced reactive ion plating. Density and temperature of the plasma generated by the HCD were investigated. It was shown that parameters such as the substrate bias voltage(0 350V) and N2 flow rate(10 180SCCM) influenced the growth, the growth, the microstructure and the color tone of the film mostly. In order to study the interface region, surface analysis by AES combined with sputter depth profiling was performed. Microhardness of the coated TiN films were measured by micro Vickers hardness tester. Also, the effect of coating parameters on composition, coating surface and fracture morphology, grain size and growth rate were examined.

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A Study on Surface Characteristics of High Tensile Brass with Molybdenum Flame Spray Treatment (고력황동의 몰리브덴 화염용사에 따른 표면 특성에 관한 연구)

  • Jung, Dong-Hyun;Kim, Hae-Ji
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.17 no.6
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    • pp.38-45
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    • 2018
  • Molybdenum flame spray coatings are widely used in industrial fields to enhance the performance of mechanical component parts such as pistons, shafts and clutches. This study investigates the surface characteristics of high tensile brass with molybdenum flame spray treatment using the clutch material for small ship. The surface characteristics after molybdenum flame spray treatment in high tensile brass were quantitatively analyzed for surface composition, coating layer thickness, friction coefficient, abrasion width and phenomenon, micro-hardness, and surface roughness.

The fire-risks of cost-optimized steel structures: Fire-resistant and hot-rolled carbon steel

  • Garcia, Harkaitz;Cuadrado, Jesus;Biezma, Maria V.;Calderon, Inigo
    • Structural Engineering and Mechanics
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    • v.78 no.1
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    • pp.67-75
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    • 2021
  • This work studies the behaviour of a steel portal frame selection under fire exposure, considering both span lengths and fire exposure times as variables. Such structures combine carbon steel (S275), fireproof micro-alloyed steel (FR), and coatings of intumescent paint with variable thicknesses, improving thereby the flame retardant behaviour of the steel structure. Thus, the main contribution of this study is the optimization of the portal frames by combining both steels, analysing the resulting costs influence on the final dimensions. Besides, the topological optimization of each steel component within the structure is also defined, in accordance with the following variables: weather conditions, span, paint thickness, and cost of steel. The results mainly confirmed that using both FR and S275 grades with intumescent painting is the Pareto optimum when considering performance, feasibility and costs of such portal frames widely used for industrial facilities.