Chemical vapor deposition of carbon on graphite by methane pyrolysis

Bammidipati, Sreekanth; Stewart, Gregory D.; Elliott, J. Richard; Gökoğlu, Süleyman A.; Purdy, M.J.

doi:10.1002/aic.690421112

Cited by 26 publications

(14 citation statements)

References 19 publications

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“…Recent simulation studies [49,50] with parameter identification based on CVD [28] and CVI [30,23] experiments tend to confirm the idea that B1, B2, and C groups (see table 1) also act in the case of deposition from methane. The main difference is now that CH 4 should be considered both as a starting point for the mechanism and as a B0 group species; the formal scheme presented for propane does not have to change, only the H 2 production stoichiometries have to be revised, as well as the rate constant #1, which is considerably lower.…”

Section: Introductionmentioning

confidence: 92%

“…Many experimental studies have shown in the past the importance of processing parameters on the pyC deposition rates and nanotexture, in various physico-chemical conditions and reactor configurations, either in CVD (plain substrate, low S V ), or in CVI (porous substrate, high S V ) [19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36]. Most of them have tried to identify some "ultimate precursor" of pyC, either light, aliphatic species, or heavy aromatic compounds such as PAHs (Polycyclic Aromatic Hydrocarbons) and polyynes.…”

Section: Introductionmentioning

confidence: 99%

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CVD and CVI of pyrocarbon from various precursors

Vignoles

Langlais

Descamps

et al. 2004

Surface and Coatings Technology

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International audienceThe control of pyrocarbon (pyC) chemical vapor infiltration (CVI) is a key issue in the processing of high-performance C/C composites with applications in aerospace parts and braking technology. For years, the precise investigation of deposition kinetics and pyC nanometerscale anisotropy has been rehearsed in chemical vapor deposition (CVD) and several variants of CVI with various pore sizes, and using mostly propane, propylene, and methane as source precursors. A literature survey and the analysis of recent experimental data have helped to understand better the role of gas-phase intermediate species in the various nanotextural transitions; a coherent modeling frame, which is suitable for propane, propylene, and methane—the latter having a neatly lower reactivity—has been set up and tested against experimental results from independent teams. The relation between nanotexture and processing conditions is then explained

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Section: Introductionmentioning

confidence: 92%

Section: Introductionmentioning

confidence: 99%

CVD and CVI of pyrocarbon from various precursors

Vignoles

Langlais

Descamps

et al. 2004

Surface and Coatings Technology

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“…(17), which is permissible because a pseudo-steady state C profile is achieved in a short amount of time (i.e., compared to the time scale over which ⑀ changes). Note that ␣ 2 is dimensionless and that ␤ has units of inverse time.…”

Section: Formulationmentioning

confidence: 99%

Optimization of chemical vapor infiltration with simultaneous powder formation

2000

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A key difficulty in isothermal, isobaric chemical vapor infiltration is the long processing times that are typically required. With this in mind, it was important to minimize infiltration times. This optimization problem was addressed here, using a relatively simple model for dilute gases. The results provided useful asymptotic expressions for the minimum time and corresponding conditions. These approximations were quantitatively accurate for most cases of interest, where relatively uniform infiltration was required. They also provided useful quantitative insight in cases where less uniformity was required. The effects of homogeneous nucleation were also investigated. This does not effect the governing equations for infiltration of a porous body; however, powder formation can restrict the range of permissible infiltration conditions. This was analyzed for the case of carbon infiltration from methane.

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“…The CVD of carbon implies that the precursor hydrocarbon, which is often methane [2][3][4], propane [5][6][7], or sometimes unsaturated hydrocarbons such as propylene [8,9] and ethylene [10][11][12], is heated to the deposition temperature, resulting in complex gas-phase reactions (homogeneous pyrolysis reactions) that are competing or interacting with complex surface reactions (heterogeneous deposition reactions). Gas-phase reactions of light hydrocarbons are synthesis reactions in which a wide variety of molecules and radicals, from the smallest species of hydrogen radical to larger species of polycyclic aromatic hydrocarbon (PAH), are formed.…”

Section: Introductionmentioning

confidence: 99%