Formation mechanism and morphology of large branched carbon nano-structures

Devaux, Xavier; Tsareva, Svetlana Yu.; Kovalenko, A.N.; Жариков, Е. В.; McRae, E.

doi:10.1016/j.carbon.2008.12.055

Cited by 14 publications

(7 citation statements)

References 24 publications

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“…2c,d further confirm the CNC fusing. This fusing phenomenon of carbon nanomaterials can also be found in branched carbon nano-structures 31 . Additionally, it was suggested that Y-shaped carbon nanotubes were formed by fusing of adjacent tubes as a result of the incremental growth of multiple graphene layers around the carbon nanotubes 32 .…”

Section: Resultsmentioning

confidence: 74%

Y-junction carbon nanocoils: synthesis by chemical vapor deposition and formation mechanism

Ding

Wang

Geng

et al. 2015

Sci Rep

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Y-junction carbon nanocoils (Y-CNCs) were synthesized by thermal chemical vapor deposition using Ni catalyst prepared by spray-coating method. According to the emerging morphologies of Y-CNCs, several growth models were advanced to elucidate their formation mechanisms. Regarding the Y-CNCs without metal catalyst in the Y-junctions, fusing of contiguous CNCs and a tip-growth mechanism are considered to be responsible for their formation. However, as for the Y-CNCs with catalyst presence in the Y-junctions, the formation can be ascribed to nanoscale soldering/welding and bottom-growth mechanism. It is found that increasing spray-coating time for catalyst preparation generates agglomerated larger nanoparticles strongly adhering to the substrate, resulting in bottom-growth of CNCs and appearance of the metal catalyst in the Y-junctions. In the contrary case, CNCs catalyzed by isolated smaller nanoparticles develop Y-junctions with an absence of metal catalyst by virtue of weaker adhesion of catalyst with the substrate and tip-growth of CNCs.

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Section: Resultsmentioning

confidence: 74%

Y-junction carbon nanocoils: synthesis by chemical vapor deposition and formation mechanism

Ding

Wang

Geng

et al. 2015

Sci Rep

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“…Therefore, right combination of these three components makes it possible to selectively synthesize various types of carbon nanofilaments, ranging from SWCNTs and MWCNTs to CNFs. The synthesis of carbon nanofilaments by CCVD method is based on the catalytic decomposition of a gaseous or volatile compound of carbon source (methane, carbon monoxide or acetylene, C 2 H 4 , methanol/ethanol, benzene (Devaux et al, 2009), on a variety of transition metals (usually iron, cobalt, nickel and their alloys; palladium is rarely employed as a catalyst for solid carbon deposition- Atwater, et. al., 2009), either in a powdered or supported form as the catalytic entities (which also serve as nucleation sites for the initiation of nanocarbon growth), over the temperature range 400-1000 0 C. The carrier gas is argon, hydrogen, nitrogen.…”

Section: Catalytic Chemical Vapour Deposition (Ccvd) Methodsmentioning

confidence: 99%

“…Other models for growing CNFs were proposed by Oberlin et al, 1976, Koch et al, 1985, Zheng et al, 2004. Formation mechanism of large branched carbon nano-structures has been presented by Devaux et al, 2009. Examination of synthesized CNFs by TEM and SEM reveals the basic microstructure of graphitic CNFs.…”

Section: Wwwintechopencommentioning

confidence: 97%

Electrochemical and Adsorption Properties of Catalytically Formed Carbon Nanofibers

Olenic¹,

Pruneanu²,

Almăşan³

et al. 2010

Nanofibers

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“…The slip through effect makes the mechanism of drawing fibers, which is responsible to increasing the cracking resistance of ceramomatrix composites, less effective. It should also be noted that the effect of carbon fiber structures on sintering and the microstructure of the material obtained has not been studied in detail.The objectives of the present work are to develop a technology for the material Al 2 O 3 -CNT and to study the effect of the conditions of calcination and concentration of CNTs on the microstructure and properties of the material.The multilayer carbon nanotubes, ranging in diameter from 30 nm, used in the present work for implantation into ceramic material were obtained by catalytic pyrolysis of benzene at 980°C with the use of ferrocene as a precatalyst [6]. The CNTs were first treated in acids to remove particles of the catalyst and amorphous carbon impurities.…”

mentioning

confidence: 99%

“…The multilayer carbon nanotubes, ranging in diameter from 30 nm, used in the present work for implantation into ceramic material were obtained by catalytic pyrolysis of benzene at 980°C with the use of ferrocene as a precatalyst [6]. The CNTs were first treated in acids to remove particles of the catalyst and amorphous carbon impurities.…”

mentioning

confidence: 99%

Carbon nanotube reinforced corundum-based composite material

et al. 2011

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A new composite ceramic material based on corundum and reinforced with multilayer carbon nanotubes (CNTs) obtained by catalytic pyrolysis has been developed. Regimes for vacuum calcination and preliminary treatment of the initial mix have been determined; the compositions of the ceramic matrix, the concentration of the CNTs, and other technological parameters have been optimized. A uniform distribution of CNTs over the entire volume of the ceramic matrix has been achieved. As a result, a composite material with a reticular-framework structure of the CNT distribution showing a 1.5 -2-fold increase of the cracking resistance has been obtained.Carbon nanotubes (CNTs) are regarded as a promising strengthening material for creating composite materials due to the structural features of CNTs (the length/diameter ratio can reach several hundred), chemical inertness, and outstanding mechanical characteristics. The introduction of CNTs into ceramic makes it possible to improve substantially the existing properties of conventional ceramic structural materials [1 -3]. The use of CNTs to reinforce ceramics based on corundum is of greatest interest. Corundum ceramic is the most common type of oxide ceramic, which because of the availability of the raw materials (alumina) and successful combination of mechanical, electrophysical, and chemical properties is widely used for manufacturing articles to be used in construction. According to the published data, when CNT 5 are introduced into a composite material based on corundum ceramic in amounts less than 2.5 vol.% the plasticity of the ceramic samples increases and the bending strength also increases by more than 25% and the cracking resistance increases by 70% [4,5].However, there are a number of problems that limit the use of CNTs in ceramic. In the first place, it is difficult to separate the bundles and attain a uniform distribution of the CNTs over the volume, and in addition the "slip through effect" arises because of poor binding of the nanotubes with the ceramic matrix. The slip through effect makes the mechanism of drawing fibers, which is responsible to increasing the cracking resistance of ceramomatrix composites, less effective. It should also be noted that the effect of carbon fiber structures on sintering and the microstructure of the material obtained has not been studied in detail.The objectives of the present work are to develop a technology for the material Al 2 O 3 -CNT and to study the effect of the conditions of calcination and concentration of CNTs on the microstructure and properties of the material.The multilayer carbon nanotubes, ranging in diameter from 30 nm, used in the present work for implantation into ceramic material were obtained by catalytic pyrolysis of benzene at 980°C with the use of ferrocene as a precatalyst [6]. The CNTs were first treated in acids to remove particles of the catalyst and amorphous carbon impurities.MgO-alloyed Al 2 O 3 was used as the ceramic matrix. The addition of MgO, which is widely used in practice in the amounts 0.2 -1...

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Formation mechanism and morphology of large branched carbon nano-structures

Cited by 14 publications

References 24 publications

Y-junction carbon nanocoils: synthesis by chemical vapor deposition and formation mechanism

Y-junction carbon nanocoils: synthesis by chemical vapor deposition and formation mechanism

Electrochemical and Adsorption Properties of Catalytically Formed Carbon Nanofibers

Carbon nanotube reinforced corundum-based composite material

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