Preparation and properties of coiled carbon fibers by the catalitic pyrolysis of acetylene

Motojima, Seiji; Hasegawa, Isao; Kagiya, S.; Asakura, Shukuji; Kawaguchi, Masayuki; Iwanaga, Hiroshi

doi:10.1051/jp4:1993383

Cited by 4 publications

(5 citation statements)

References 10 publications

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“…However, the number of MCCFs was found to be greater when grown in the presence of a Ni catalyst of the order of nanometers. This result is contradictory to the findings of Motojimia et al's study [8] in which they indicated that the maximum yield of MCCF was observed when the particle size of Ni was in the order of micrometers.…”

Section: Effect Of the Size Of The Ni Particlecontrasting

confidence: 98%

“…The size of the pitch of the coil decreased with increasing reaction time as shown in figures 8(a) and (b). Similar observations were reported elsewhere [8].…”

Section: Effect Of Reaction Temperaturesupporting

confidence: 93%

“…Acetylene is a common organic material, which is used as carbon source [6,7]. A mixture of acetone and acetylene has also been reported in order to obtain MCCFs [8]. However, a straight carbon fiber was formed when propane was used as a carbon source in the study of Chen and Motojima [9].…”

Section: Introductionmentioning

confidence: 99%

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Development and characterization of micro-coil carbon fibers by a microwave CVD system

Varadan

Hollinger²,

Xie

et al. 2000

Smart Mater. Struct.

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Nano-and micro-coiled carbon fibers find applications in electronic devices, electromagnetic absorbers and filters. Smart devices can be conceived using tunable films on these fibers and tunable host materials. A new method of producing helical carbon fibers with dimensions in the order of less than a micrometer has been developed using microwaves. The microwave CVD system presented here eliminates the use of the toxic impurity gas, which is required in the conventional method. Both methods involve gas phase reactions over a substrate seeded with an appropriate catalyst. Micro-coiled carbon fiber (MCCF) was grown by the catalytic pyrolysis of acetylene on a silicon carbide substrate on which nickel metal powder was dispersed as a catalyst. Various factors, for example flow rate of the gas, particle size of the catalyst, effect of reaction temperature and time, were studied in order to understand the growth of the microwave synthesis of MCCF. MCCFs were also synthesized by a conventional method in the presence of thiophene as an impurity gas so that a comparison can be made with the materials obtained by the microwave system. The morphology of the final products were investigated by scanning electron microscopy. The carbon products obtained by traditional and microwave methods were investigated with the help of x-ray diffraction. The effect of various reaction conditions on the morphological development of a MCCF were examined in detail. Furthermore, a brief study was made on the microwave absorbing property of the MCCF.

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Section: Effect Of the Size Of The Ni Particlecontrasting

confidence: 98%

“…The size of the pitch of the coil decreased with increasing reaction time as shown in figures 8(a) and (b). Similar observations were reported elsewhere [8].…”

Section: Effect Of Reaction Temperaturesupporting

confidence: 93%

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Development and characterization of micro-coil carbon fibers by a microwave CVD system

Varadan

Hollinger²,

Xie

et al. 2000

Smart Mater. Struct.

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show abstract

“…The addition of a small amount of sulfur impurity during the overall reaction has been noticed for one of the methods to enhance the carbon coils production yield and reproducibility (6). Motojima et al first reported the regularly microcoiled carbon fibers with high reproducibility by the catalytic pyrolysis of acetylene containing a small amount of sulfur impurity (7,8). Sulfur impurity was mostly incorporated in the form of hydrogen sulfide (H 2 S), carbon disulfide (CS 2 ), and thiophene (C 4 H 4 S) (9)(10)(11).…”

Section: Introductionmentioning

confidence: 99%

Growth Mode for Carbon Micro Coils having Double Helix Geometries

2013

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Formation of carbon coils were investigated according to the injection starting stage of an incorporated additive gas (SF 6 ) flow during the overall reaction. Among the different injection stage of SF 6 flow, the initial stage is most effective for the formation of the microsized carbon coils. The formation of carbon coils was also investigated step by step during the reaction. In an early step of the reaction, merely carbon nanofilaments could be observed on the sample. With increasing the reaction time, the formation of the carbon coils was initiated and their densities increased. The double helix geometry of the microsized carbon coils seemed to be developed by the precipitating carbon elements from the spinning catalyst. Based on the close investigating results of the coil head area, the detailed growth mode for the double helix geometry of the microsized carbon coils was proposed and discussed.

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“…We have obtained very regularly shaped micro-coiled carbon fibers (referred to as "carbon coils" hereafter). The carbon coils have a constant coil diameter of 1-10 m without coil gap when prepared by Ni-catalyzed pyrolysis of acetylene at 700-850 • C [3][4][5][6].…”

Section: Introductionmentioning

confidence: 99%

Vapor phase preparation and properties of NbN/C(carbon coils)/NbN–NbN micro-coils/micro-tubes

Motojima

Ueshima

2005

Journal of Alloys and Compounds

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Preparation and properties of coiled carbon fibers by the catalitic pyrolysis of acetylene

Cited by 4 publications

References 10 publications

Development and characterization of micro-coil carbon fibers by a microwave CVD system

Development and characterization of micro-coil carbon fibers by a microwave CVD system

Growth Mode for Carbon Micro Coils having Double Helix Geometries

Vapor phase preparation and properties of NbN/C(carbon coils)/NbN–NbN micro-coils/micro-tubes

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