• Title, Summary, Keyword: Carbon nanotubes

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An investigation of tribology properties carbon nanotubes reinforced epoxy composites (표면 개질된 탄소나노튜브를 사용한 에폭시 복합재료의 마모특성에 관한 연구)

  • Sulong A.B.;Goak J.C.;Park Joo-Hyuk
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • pp.663-667
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    • 2005
  • Surface modified carbon nanotubes were applied into the epoxy composites to investigate its tribological property. Carbon nanotubes reinforced epoxy composites were fabricated by casting. Effects to the tribological property of loading concentrations and types of surface modification of carbon nanotubes were investigated under sliding condition using linear reciprocal sliding wear tester. The results show that the small amount of carbon nanotubes into the epoxy exhibited lower weight loss than the pure epoxy. It is concluded that the effect of an enormous aspect ratio of carbon nanotubes surface area which wider than conventional fillers that react as interface for stress transfer. As increased the contents of carbon nanotubes, the weight loss from the wear test was reduced. And the surface modified carbon nanotubes show better tribological property than as produced carbon nanotubes. It is due that a surface modification of carbon nanotubes increases the interfacial bonding between carbon nanotubes and epoxy matrix through chemical bonding. Changes in worn surface morphology are also observed by optical microscope and SEM for investigating wear behaviors. Carbon nanotubes in the epoxy matrix near the surface are exposed, because it becomes the lubricating working film on the worn surface. It reduces the friction and results in the lower surface roughness morphology in the epoxy matrix as increasing the contents of the carbon nanotubes.

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Competitive Growth of Carbon Nanotubes versus Carbon Nanofibers

  • Kim, Sung-Hoon
    • Journal of the Korean Ceramic Society
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    • v.40 no.12
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    • pp.1150-1153
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    • 2003
  • Carbon nanofilaments were formed on silicon substrate using microwave plasma-enhanced chemical vapor deposition method. The structures of carbon nanofilaments were identified as carbon nanotubes or carbon nanofibers. The formation of bamboo-like carbon nanotubes was initiated by the application of the bias voltage during the plasma reaction. The growth kinetics of bamboo-like carbon nanotubes increased with increasing the bias voltage. The growth direction of bamboo-like carbon nanotubes was vertical to the substrate.

Finite element modeling of the vibrational behavior of multi-walled nested silicon-carbide and carbon nanotubes

  • Nikkar, Abed;Rouhi, Saeed;Ansari, Reza
    • Structural Engineering and Mechanics
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    • v.64 no.3
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    • pp.329-337
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    • 2017
  • This study concerns the vibrational behavior of multi-walled nested silicon-carbide and carbon nanotubes using the finite element method. The beam elements are used to model the carbon-carbon and silicon-carbon bonds. Besides, spring elements are employed to simulate the van der Waals interactions between walls. The effects of nanotube arrangement, number of walls, geometrical parameters and boundary conditions on the frequencies of nested silicon-carbide and carbon nanotubes are investigated. It is shown that the double-walled nanotubes have larger frequencies than triple-walled nanotubes. Besides, replacing silicon carbide layers with carbon layers leads to increasing the frequencies of nested silicon-carbide and carbon nanotubes. Comparing the first ten mode shapes of nested nanotubes, it is observed that the mode shapes of armchair and zigzag nanotubes are almost the same.

Microscopic Characterization of Cement Composites with Carbon Nanotubes (탄소나노튜브가 첨가된 시멘트복합체의 미시적특성분석)

  • Kim, Young-Min;Lee, Gun Cheol
    • Proceedings of the Korean Institute of Building Construction Conference
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    • pp.176-177
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    • 2019
  • As a result of the Rietveld analysis to determine the effect of carbon nanotubes on the hydration products of cement composites, the quantitative difference of hydration products according to the addition rate of carbon nanotubes was not significant. Ettringite, an early hydration product, was measured to be slightly higher than the planes with carbon nanotubes over all ages. Therefore, it seems that carbon nanotubes have no effect on the hydration production in cement paste.

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Synthesis of self-aligned carbon nanotubes on a Ni particles using Chemical Vapour Deposition

  • Park, Gyu-Seok
    • Proceedings of the Korean Vacuum Society Conference
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    • pp.64-64
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    • 2000
  • Since its discovery in 1991, the carbon nanotube has attracted much attention all over the world; and several method have been developed to synthesize carbon nanotubes. According to theoretical calculations, carbon nanotubes have many unique properties, such as high mechanical strength, capillary properties, and remarkable electronical conductivity, all of which suggest a wide range of potential applications in the future. Here we report the synthesis in the catalytic decomposition of acetylene at ~65 $0^{\circ}C$ over Ni deposited on SiO2, For the catalyst preparation, Ni was deposited to the thickness of 100-300A using effusion cell. Different approaches using porous materials and HF or NH3 treated samples have been tried for synthesis of carbon nanotubes. It is decisive step for synthesis of carbon nanotubes to form a round Ni particles. We show that the formation of round Ni particles by heat treatment without any pre-treatment such as chemical etching and observe the similar size of Ni particles and carbon nanotubes. Carbon nanotubes were synthesized by chemial vapour deposition ushin C2H2 gas for source material on Ni coated Si substrate. Ni film gaving 20~90nm thickness was changed into Ni particles with 30~90nm diameter. Heat treatment of Ni fim is a crucial role for the growth of carbon nanotube, High-resolution transmission electron microscopy images show that they are multi-walled nanotube. Raman spectrum shows its peak at 1349cm-1(D band) is much weaker than that at 1573cm-1(G band). We believe that carbon nanotubes contains much less defects. Long carbon nanotubes with length more than several $\mu$m and the carbon particles with round shape were obtained by CVD at ~$650^{\circ}C$ on the Ni droplets. SEM micrograph nanotubes was identified by SEM. Finally, we performed TEM anaylsis on the caron nanotubes to determine whether or not these film structures are truly caron nanotubes, as opposed to carbon fiber-like structures.

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Carbon nanotube based transparent electrodes for flexible displays using liquid crystal devices

  • Shin, Jun-Ho;Lee, H.C.;Lee, J.H.;Park, S.M.;Alegaonkar, P.S.;Yoo, J.B.
    • 한국정보디스플레이학회:학술대회논문집
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    • pp.897-899
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    • 2007
  • Transparent electrodes for a flexible display based on the liquid crystal (LC) were formed by carbon nanotubes (CNTs) on polyethylene terephthalate (PET) substrates. The thin multi wall carbon nanotubes (t-MWNTs) networks for electrodes were obtained by filtration- transfer method from welldispersed CNTs solution.

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Effect of the Applied Bias Voltage on the Formation of Vertically Well-Aligned Carbon Nanotubes (탄소 나노 튜브의 수직 배향에 대한 바이어스 인가 전압의 효과)

  • Kim, Sung-Hoon
    • Korean Journal of Materials Research
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    • v.13 no.7
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    • pp.415-419
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    • 2003
  • Carbon nanotubes were formed on silicon substrate using microwave plasma-enhanced chemical vapor deposition method. The possibility of carbon nanotubes formation was related to the thickness of nickel catalyst. The growth behavior of carbon nanotubes under the identical thickness of nickel catalyst was strongly dependent on the magnitude of the applied bias voltage. High negative bias voltage (-400 V) gave the vertically well-aligned carbon nanotubes. The vertically well-aligned carbon nanotubes have the multi-walled structure with nickel catalyst at the end position of the nanotubes.

Growth of Vertically Aligned Carbon Nanotubes on Co-Ni Alloy Metal (Co-Ni 합금위에서 수직방향으로 정렬된 탄소나노튜브의 성장)

  • Ryu, Jae-Eun;Lee, Cheol-Jin;Lee, Tae-Jae;Son, Gyeong-Hui;Sin, Dong-Hyeok
    • The Transactions of the Korean Institute of Electrical Engineers C
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    • v.49 no.8
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    • pp.451-454
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    • 2000
  • We have grown vertically aligned carbon nanotubes in a large area of Co-Ni codeposited Si substrates by the thermal CVD usign $C_2H_2$ gas. Since the discovery of carbon nanotubes, growth of carbon nanotubes has been achieved by several methods such as laser vaporization, arc discharge, and pyrolysis. In particular, growth of vertically aligned nanotubes is important to flat panel display applications. Recently, vertically aligned carbon nanotubes have been grown on glass by PECVD. Aligned carbon nanotubes can be also grown on mesoporous silica and Fe patterned porous silicon using CVD. In this paper, we demonstrate that carbon nanotubes can be vertically aligned on catalyzed Si substrate when the domain density of catalytic particles reaches a certain value. We suggest that steric hindrance between nanotubes at an initial stage of the growth forces nanotubes to align vertically and each nonotubes are grown in bundle.

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Growth of vertically aligned carbon nanotubes on silicon substrates by the thermal CVD (열화학기상증착법에 의해 실리콘 기판위에 수직방향으로 정렬된 탄소나노튜브의 성장)

  • 이철진;김대운;이태재;박정훈;손권희;류승철;최영철;박영수;최원석
    • Proceedings of the IEEK Conference
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    • pp.275-278
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    • 1999
  • We have grown vertically aligned carbon nanotubes in a large area of Co-Ni codeposited Si substrates by the thermal CVD using $C_2$H$_2$gas. Since the discovery of carbon nanotubes, Synthesis of carbon nanotubes for mass production has been achieved by several methods such as laser vaporization, arc discharge, and pyrolysis. In particular, growth of vertically aligned nanotubes is of technological importance for applications to FED. Recently, vertically aligned carbon nanotubes have been grown on glass by PECVD. Aligned carbon nanotubes can be also grown on mesoporous silica and Fe patterned porous silicon using CVD. Despite such breakthroughs in the growth, the growth mechanism of the alignment are still far from being clearly understood. Furthermore, FED has not been clearly demonstrated yet at a practical level. Here, we demonstrate that carbon nanotubes can be vertically aligned on catalyzed Si substrate when the domain density reaches a certain value. We suggest that steric hindrance between nanotubes at an initial stage of the growth forces nanotubes to align vertically and then nanotubes are further grown by the cap growth mechanism.

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