A combined CFD modeling and experimental study of pyrolytic carbon deposition

Kehan Yu, Clifford C. Hayman, S. Manjunath, Wei Fan, Ina T. Martin, Heidi B. Martin, R. Mohan Sankaran

Research output: Contribution to journalArticlepeer-review

Abstract

Understanding the chemical reaction mechanism and deposition kinetics is of great importance to guide the production of pyrolytic carbon (PC). A practical approach to mimic the commercial chemical vapor deposition (CVD) process and eventually predict the PC deposition rate is highly desired. In this work, a simplified two-step reaction mechanism was proposed for the CVD of PC, with the first step in the gas phase and the second step on the substrate surface. The kinetic parameters were determined by trial and error using a computational fluid dynamics simulation. The velocity, temperature, and concentration profiles in a cold-wall, forced-flow reactor were modeled based on the geometry and experimentally determined boundary conditions. The computed PC deposition rates for substrate temperatures between 700 and 3000 °C were in good accordance with experimental results. Rate limiting steps were observed for both the deposition experiments and simulations. Mass-transport-limited and reaction-limited regimes were identified in wide temperature and flow rate ranges. A higher deposition rate was found in a cold-wall reactor compared with those in an insulated reactor or a hot-wall reactor. Finally, the PC microstructure was characterized using optical microscopy, scanning electron microscopy, Raman spectroscopy, and X-ray diffraction, demonstrating progressive development of graphitization with increasing deposition temperature.

Original languageEnglish (US)
Pages (from-to)173-178
Number of pages6
JournalDiamond and Related Materials
Volume70
DOIs
StatePublished - Nov 1 2016
Externally publishedYes

Keywords

  • Chemical vapor deposition
  • Computational fluid dynamics
  • Pyrolytic carbon
  • Reaction kinetics

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Chemistry(all)
  • Mechanical Engineering
  • Materials Chemistry
  • Electrical and Electronic Engineering

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