1. Chemistryand Kinetics of Heterogeneous Reaction Mechanismfor Chemical Vapor Infiltration of Pyrolytic Carbon from Propane.
- Author
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Tang, Z. P., Li, A. J., Zhang, Z. W., Ma, X., Wang, W., Fang, J. M., and Bai, R. C.
- Subjects
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REACTION mechanisms (Chemistry) , *CHEMICAL vapor deposition , *SEEPAGE , *PYROLYTIC graphite , *PROPANE , *SURFACE chemistry - Abstract
A heterogeneous reaction mechanismbased on elementary reactionsteps is proposed for the prediction of pyrolytic carbon depositionin chemical vapor infiltration, involving 72 surface species and 277surface elementary reactions. A “prototype” gas-phasereaction is chosen to match with the corresponding surface reaction,and correction methods for kinetic data are also proposed for threekinds of surface reactions (i.e., surface/gas reactions, unimolecularsurface reactions, surface/surface reactions) in the present work.Simulation results of deposition kinetics and gas-phase compositionsof propane pyrolysis are validated by previously published experimentalresults of Marquaire’s group, with a surface to volume ratiofrom 5 to 175 cm–1and temperature from 1173 to1323 K. The reaction pathways of the heterogeneous surface reactionsand homogeneous gas-phase reactions are studied on the basis of thereaction flow rate analysis. An acceptable agreement indicates thatthe present heterogeneous reaction mechanism is reasonable, and acetylene,ethylene, and benzene are recognized as the main precursors of thepyrolytic carbon deposition at the present processing conditions. [ABSTRACT FROM AUTHOR]
- Published
- 2014
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