Raman-scattering and transmission-electron-microscopy studies of fluorine-intercalated graphite fibers<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">C</mml:mi></mml:mrow><mml:mrow><mml:mi mathvariant="italic">x</mml:mi></mml:mrow></mml:msub></mml:mrow></mml:math>F (7.8≥<i>x</i>≥2.9)

Rao, Apparao M.; Fung, A. W. P.; Vittorio, S.L. di; Dresselhaus, M. S.; Dresselhaus, G.; Endo, Morinobu; Oshida, K.; Nakajima, Tsuyoshi

doi:10.1103/physrevb.45.6883

Cited by 29 publications

(21 citation statements)

References 18 publications

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“…5 F. We obtain tyrjical in-plane coherence lengths of 11.5 A and 6.8 A for the C9.0F and C 45 F fibers, respectively. Since the in-plane coherence lengths of the graphene planes in C X F fibers, obtained by Raman scattering measurements, are much higher, on the order of 40 A for a C 4 5 F fiber, 14 we argue that the very short coherence lengths that are observed in the TEM pictures are associated with the random structure of the fluorine intercalate. The very small inplane coherence distances that are observed indicate that the fluorine is not in registry with the carbon layers, allowing a range of local stoichiometries.…”

Section: -1mentioning

confidence: 67%

Image analysis of TEM pictures of fluorine-intercalated graphite fibers

et al. 1993

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A digitization of the TEM pictures of fluorine-intercalated graphite fibers has been used to carry out quantitative measurements of the defect structure of this material. Emphasis is given to both the computer analysis technique and to the characterization of the defects. The amount of intercalation-induced disorder increases with increasing fluorine concentration. The fast Fourier transform of the digitized TEM image exhibits two diffuse spots, corresponding to the c-axis repeat distance of the intercalation compound. The length and width of the spots are a measure of the out-of-plane and in-plane disorder present in the fibers. From the fast Fourier transform, the distribution of interlayer repeat distances and the fraction of unintercalated graphite regions throughout the material is obtained. By selecting a small range of repeat distances and carrying out an inverse fast Fourier transform, the spatial distribution of material with a given repeat distance is determined. Regions with the same repeat distance are found to form islands. This particular feature of fluorine graphite intercalation compounds, as well as the nature of the microscopic defects and the staging behavior of fluorine-intercalated graphite fibers, are discussed in connection with the dual covalent and ionic nature of the carbon-fluorine bond in fluorine-intercalated graphite.

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Section: -1mentioning

confidence: 67%

Image analysis of TEM pictures of fluorine-intercalated graphite fibers

et al. 1993

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“…It indicates that the structure is totally composed of puckered fluorocarbon layers (the carbon atoms only present sp 3 hybridization). From T FPT = 150-450°C, spectra show a downshift of the D (and probably D 0 ) band attributed both to electronic effect of fluorine and increase of disorder as already mentioned in previous works [17,[21][22][23][24]. The fact that the fluorination of carbon is completed for B(500) and B(550) materials (covalent C-F bonds resulting in the armchair conformation of carbon rings) which present the highest friction coefficient values seems to confirm that the friction properties of the compounds are improved if the graphitic structure is partially maintained.…”

Section: Intrinsic Tribologic Properties Of Graphite Fluoridesmentioning

confidence: 68%

“…It indicates that the structure is totally composed of puckered fluorocarbon layers (the carbon atoms only present sp 3 hybridization). From T FPT = 150°C to 450°C, spectra show a downshift of the D band attributed both to electronic effect of fluorine and increase of disorder [17,[21][22][23][24]. The two lines appearing at 1464 cm -1 and 1527 cm -1 are the emission lines of a vapor mercury lamp used as internal standard which allow us to determine precisely the Raman bandshifts in the collected spectra [25]) as a function of atomic F/C ratio (determined from weight uptake [14,15]) for B(T FPT ) and C(T FPT ) materials.…”

Section: Intrinsic Tribologic Properties Of Graphite Fluoridesmentioning

confidence: 99%

Tribological Properties of Room Temperature Fluorinated Graphite Heat-Treated Under Fluorine Atmosphere

Delbé¹,

Pandorf²,

Himmel³

et al. 2009

Tribol Lett

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This work is concerned with the study of the tribologic properties of room temperature fluorinated graphite heat-treated under fluorine atmosphere. The fluorinated compounds all present good intrinsic friction properties (friction coefficient in the range 0.05-0.09). The tribologic performances are optimized if the materials present remaining graphitic domains (influenced by the presence of intercalated fluorinated species) whereas the perfluorinated compounds, where the fluorocarbon layers are corrugated (armchair configuration of the saturated carbon rings) present higher friction coefficients. Raman analyses reveal that the friction process induces severe changes in the materials structure especially the partial rebuilding of graphitic domains in the case of perfluorinated compounds which explains the improvement of l during the friction tests for these last materials.

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“…As it can be noticed for the two families, a significant downshift of the D band is observed as a function of increasing F/C ratio. This phenomenon is attributed both to size reduction of graphitic domains induced by the fluorination process and to the creation of covalent C-F bonds [29,37,38]. The increase of the relative intensity of the D band compared to the G one is attributed to the size reduction of the graphitic domains [39].…”

Section: Morphology and Structure Of The Nanoparticlesmentioning

confidence: 88%

Friction Properties of Fluorinated Carbon Nanodiscs and Nanocones

Pandorf¹,

Himmel²,

Mansot³

et al. 2010

Tribol Lett

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The tribologic properties of carbon nanodiscs and nanocones and their fluorinated derivatives are investigated and correlated to their structure and chemical composition (atomic fluorine/carbon ratio). Two families of products are studied obtained by fluorination of ill ordered and highly graphitized carbon nanodiscs and nanocones. The studies clearly point out that friction properties of the nanoparticles are strongly dependent on the structure of the initial carbonaceous compounds. Better tribologic behaviour is obtained when the initial nanoparticles structure is highly ordered (graphitized particles). In that case, an optimum of fluorination rate is put in evidence.

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Raman-scattering and transmission-electron-microscopy studies of fluorine-intercalated graphite fibersCxF (7.8≥x≥2.9)

Cited by 29 publications

References 18 publications

Image analysis of TEM pictures of fluorine-intercalated graphite fibers

Image analysis of TEM pictures of fluorine-intercalated graphite fibers

Tribological Properties of Room Temperature Fluorinated Graphite Heat-Treated Under Fluorine Atmosphere

Friction Properties of Fluorinated Carbon Nanodiscs and Nanocones

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