• Title/Summary/Keyword: Carbon coating

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Effect of Ni Bond Coat on Adhesive Properties of Fe Coating Thermal Sprayed on Al Substrate (Ni 본드코팅이 Al 기지에 고온 용사 코팅된 Fe 코팅층의 접합특성에 미치는 영향)

  • Kwon, Eui-Pyo;Kim, Dae-Young;Lee, Jong-Kweon
    • Korean Journal of Materials Research
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    • v.26 no.10
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    • pp.542-548
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    • 2016
  • The influence of NiCrAlY bond coating on the adhesion properties of an Fe thermal coating sprayed on an Al substrate was investigated. By applying a bond coat, an adhesion strength of 21MPa was obtained, which was higher than the 15.5MPa strength of the coating without the bond coat. Formation of cracks at the interface of the bond coat and the Al substrate was suppressed by applying the bond coat. Microstructural analysis of the coating interface using EBSD and TEM indicated that the dominant bonding mechanism was mechanical interlocking. Mechanical interlocking without crack defects in the coating interface may improve the adhesion strength of the coating. In conclusion, the use of an NiCrAlY bond coat is an effective method of improving the adhesion properties of thermal sprayed Fe coatings on Al substrates.

Mechanical Property Evaluation of Diamond-like Carbon Coated by PE-CVD (PE-CVD방법을 이용한 DLC 박막의 기계적특성 평가)

  • Kang Seog Ju;Yi Jin-Woo;Kim Seock Sam
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • 2003.11a
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    • pp.368-376
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    • 2003
  • In this research, DLC thin films are produced as several hundred nm thickness by PE-CVD method. And then these thin films are estimated tribological characteristics to find out useful possibilities as a protecting film for high-quality function and life extension at MEMs by mechanical properties observation . These are measured thickness and residual stress of DLC coating. Compared after measuring friction coefficient, adhesion force, hardness, cohesive force of coating films. As results all test, we can decide several conclusions. First, friction coefficient decreased, as the load increased. otherwise, friction coefficient increased, as thickness of coating film increased under low load$(1\~50mN)$. Secod, adhesion force increased as thickness of coating films. Third, hardness of coating film is affected by substrate coating film when it is less than thickness of 300nm and it has general hardness of DLC coating film when it is more than thickness of 500nm. Fourth, cohesive force of coating film is complexly affected by hardness, adhesion force, residual stress, etc.

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Effect of Unidirectional Carbon Fiber Sheet Manufacturing Process Using Coated Glass Fiber and Carbon Fiber on Concrete Reinforcement (유리섬유 코팅사와 탄소섬유를 이용한 일방향 탄소섬유시트 제조공정이 콘크리트 보강에 미치는 영향)

  • Kwon, Jieun;Kwon, Sunmin;Chae, Seehyeon;Jeong, Yedam;Kim, Jongwon
    • Textile Coloration and Finishing
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    • v.34 no.3
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    • pp.185-196
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    • 2022
  • In this study, carbon fiber and coated glass fiber are applied to warp and weft fiber in order to reduce the amount of carbon fiber used in carbon fiber fabrics, which are often used for reinforcement of building structures. A low-cost thermoplastic resin was coated on glass fibers to prepare a shape-stabilizing glass fiber. A unidirectional carbon fiber sheet was manufactured using the prepared coated glass fiber and carbon fiber. In order to identify whether it can be used for reinforcing architectural and civil structures, it was attached to a concrete specimen and its mechanical properties were analyzed. The optimum manufacturing conditions for the coated glass fiber were 0.3 mm in diameter of the coating nozzle, the coating temperature was 190 ℃, and the coating speed was 0.3 m/s. 14 mm was optimal for the weft spacing of the coated glass fiber. The flexural strength of the concrete reinforced with the manufactured unidirectional carbon fiber sheet was slightly lower than that of the concrete reinforced with carbon fiber fabric, but it was confirmed that the reinforcement effect was better when the amount of carbon fiber was considered.

Preparation and Characterization of Hybrid Ozone Resistance Coating Film Using Carbon Nanotube (탄소나노튜브를 이용한 하이브리드 내오존성 코팅 막의 제조 및 특성)

  • Kim, Sung Rae;Lee, Sang Goo;Yang, Jeong Min;Lee, Jong Dae
    • Polymer(Korea)
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    • v.38 no.5
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    • pp.573-579
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    • 2014
  • The effect of synthesis conditions such as carbon nanotube (CNT), 2,2,2-trifluoroethylmethacrylate (3FMA), and composition of organic-inorganic material in ozone resistance and surface characteristics of ultraviolet cured organic-inorganic hybrid coating film has been investigated. Coating solution was prepared using tetraethoxysilane (TEOS), silane coupling agent methacryloyloxypropyltrimethoxysilane (MPTMS), 3FMA, various organic materials with acrylate group, and CNT, then bar-coated on substrates using applicator, and densified by UV-curing. It was found that ozone resistance and adhesion of the coating film were strongly dependent upon contents of TEOS, 3FMA, and CNT. Especially, ozone resistance, adhesion, and surface hardness of coating film with CNT were improved, relatively. Ozone resistance of coating film with a high TEOS content was increased, but adhesion was decreased. In addition, it was also found that ozone resistance of coating film was increased with contents of 3FMA. On the other hand, surface hardness was decreased with increase of 3FMA.

Carbon-based Materials for Atomic Energy Reactor

  • Sathiyamoorthy, D.;Sur, A.K.
    • Carbon letters
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    • v.4 no.1
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    • pp.36-39
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    • 2003
  • Carbon and carbon-based materials are used in nuclear reactors and there has recently been growing interest to develop graphite and carbon based materials for high temperature nuclear and fusion reactors. Efforts are underway to develop high density carbon materials as well as amorphous isotropic carbon for the application in thermal reactors. There has been research on coated nuclear fuel for high temperature reactor and research and development on coated fuels are now focused on fuel particles with high endurance during normal lifetime of the reactor. Since graphite as a moderator as well as structural material in high temperature reactors is one of the most favored choices, it is now felt to develop high density isotropic graphite with suitable coating for safe application of carbon based materials even in oxidizing or water vapor environment. Carboncarbon composite materials compared to conventional graphite materials are now being looked into as the promising materials for the fusion reactor due their ability to have high thermal conductivity and high thermal shock resistance. This paper deals with the application of carbon materials on various nuclear reactors related issues and addresses the current need for focused research on novel carbon materials for future new generation nuclear reactors.

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A study on Zn corrosion resistance of WC spray coating sealed with carbon nanotube suspensions (탄소 나노튜브 혼합액으로 봉공처리된 텅스텐 카바이드 용사층의 아연 내부식성에 대한 연구)

  • Kim, Bong-Hun;Lee, Bo-Young
    • Journal of Welding and Joining
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    • v.33 no.1
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    • pp.49-53
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    • 2015
  • An experimental study was conducted to investigate the effect of carbon nanotubes on the zinc corrosion resistance of sealing layer formed on the Tungsten Carbide spray coating. Using the nanotubes, a sealing agent in the form of solid-liquid suspensions was made and applied to the surface of spray coating. A series of experiments, consisted of three stages such as preparation of test piece, molten-pot immersion test, and evaluation of micro structure, were undertaken to demonstrate complicated interaction existing between zinc ions and sealing layer containing the nanotubes. Experimental results showed newly developed sealing layer were less susceptible to corrosion and thus coated layer was well protected even in the case of 10 days exposure. Comparison of the micro structure after molten pot test also indicated that carbon nanotubes still remained in the matrix and organized more reliable frame work constituted with boron nitride and chromium compound. It was revealed that carbon nanotubes in the sealing layer played positive role to enhance zinc corrosion resistance in the perspective of both fibrous structure and inherent chemical stability.

Li Ion Diffusivity and Improved Electrochemical Performances of the Carbon Coated LiFePO4

  • Park, Chang-Kyoo;Park, Sung-Bin;Oh, Si-Hyung;Jang, Ho;Cho, Won-Il
    • Bulletin of the Korean Chemical Society
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    • v.32 no.3
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    • pp.836-840
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    • 2011
  • This study examines the effects of a carbon coating on the electrochemical performances of $LiFePO_4$. The results show that the capacity of bare $LiFePO_4$ decreased sharply, whereas the $LiFePO_4$/C shows a well maintained initial capacity. The Li ion diffusivity of the bare and carbon coated $LiFePO_4$ is calculated using cyclic voltammetry (CV) to determine the correlation between the electrochemical performance of $LiFePO_4$ and Li diffusion. The diffusion constants for $LiFePO_4$ and $LiFePO_4$/C measured from CV are $6.56{\times}10^{-16}$ and $2.48{\times}10^{-15}\;cm^2\;s^{-1}$, respectively, indicating considerable increases in diffusivity after modifications. The Li ion diffusivity (DLi) values as a function of the lithium content in the cathode are estimated by electrochemical impedance spectroscopy (EIS). The effects of the carbon coating as well as the mechanisms for the improved electrochemical performances after modification are discussed based on the diffusivity data.

Mechanical Characteristics of Crystalline Carbon Nitride Films Grown by Reactive Sputtering (반응성 스퍼터링으로 성장된 결정성 질화탄소막의 기계적 특성)

  • 이성필;강종봉
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.15 no.2
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    • pp.147-152
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    • 2002
  • Carbon nitride thin films were deposited by reactive sputtering for the hard coating materials on Si wafer and tool steels. When the nitrogen content of carbon nitride film on tool steel is 33.4%, the mean hardness and elastic modulus are 49.34 GPa and 307.2 GPa respectively. The nitrided or carburised surface acts as the diffusion barrier which shows better adhesion of carbon nitride thin film on the steel surface. To prevent nitrogen diffusion from the film, steel substrate can be saturated by nitrogen forming a Fe$_3$N layer. The desirable structure at the surface after carburising is martensite, but sometimes, due to high carbon content an proeutectoid Fe$_3$C structure may form at the grain boundaries, leaving the overall surface brittle and may cause defects.

Micromechanical Analysis for Effective Properties of HfC-coated Carbon/Carbon Composites (HfC-코팅 C/C 복합재료의 유효 물성 산출을 위한 미시역학 전산 해석)

  • Roh, Kyung Uk;Kim, Ho Seok;Shin, Eui Sup
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.48 no.12
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    • pp.961-968
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    • 2020
  • In this study, the effective thermal conductivity and elastic modulus of heat-resistant coating materials are analyzed by using micromechanical computational models. Three-dimensional computational models for HfC-coated carbon/carbon composites were created with Simpleware, and finite element analysis was performed. The porosity and thickness changes in the coating layer were taken into account to identify the tendency of effective material properties. In addition, the coupon specimen was produced to compare the thermal conductivity measured by experiments with the one obtained by finite element analysis according to temperature changes, and the analysis results were close to the measured values. This confirms that micromechanical computational analysis is appropriate in the calculation of effective material properties of coating composites.

Indentation and Sliding Contact Analysis between a Rigid Ball and DLC-Coated Steel Surface: Influence of Supporting Layer Thickness (강체인 구와 DLC 코팅면 사이의 압입 및 미끄럼 접촉해석: 지지층 두께의 영향)

  • Lee, JunHyuk;Park, TaeJo
    • Tribology and Lubricants
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    • v.30 no.4
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    • pp.199-204
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    • 2014
  • Various heat-treated and surface coating methods are used to mitigate abrasion in sliding machine parts. The most cost effective of these methods involves hard coatings such as diamond-like carbon (DLC). DLC has various advantages, including a high level of hardness, low coefficient of friction, and low wear rate. In practice, a supporting layer is generally inserted between the DLC layer and the steel substrate to improve the load carrying capacity. In this study, an indentation and sliding contact problem involving a small, hard, spherical particle and a DLC-coated steel surface is modeled and analyzed using a nonlinear finite element code, MARC, to investigate the influence of the supporting layer thickness on the coating characteristics and the related coating failure mechanisms. The results show that the amount of plastic deformation and the maximum principal stress decrease with an increase in the supporting layer thickness. However, the probability of the high tensile stress within the coating layer causing a crack is greatly increased. Therefore, in the case of DLC coating with a supporting layer, fatigue wear can be another important cause of coating layer failure, together with the generally well-known abrasive wear.