Modeling of the Role of Atomic Hydrogen in Heat Transfer During Hot Filament Assisted Deposition of Diamond

Abstract

The temperature and atomic hydrogen concentration profiles in a hot filament type diamond deposition reactor were determined experimentally and theoretically to demonstrate that the reaction of atomic hydrogen on the substrate surface plays an important role in the heating of the substrate. For a given filament temperature, the substrate temperature in helium was significantly lower than that in either pure hydrogen or 1 % methane-hydrogen atmospheres. The presence of small amounts of methane in hydrogen did not have any significant effect in influencing the shape of the atomic hydrogen concentration profile. In the shape between the filament and the substrate, the concentration field is established mainly due to the diffusive mixing of the atomic hydrogen with the molecular hydrogen and other species in the gas phase. Homogeneous chemical reactions in the gas phase do not significantly affect the atomic hydrogen concentration distribution in this region.

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Document Details

Document Type
Technical Report
Publication Date
May 12, 1992
Accession Number
ADA250607

Entities

People

  • K. Tankala
  • T. Debroy

Organizations

  • Pennsylvania State University

Tags

Communities of Interest

  • Weapons Technologies

DTIC Thesaurus Topics

  • Chemical Reactions
  • Chemistry
  • Computational Fluid Dynamics
  • Engineering
  • Experimental Data
  • Flow Rate
  • Fluid Flow
  • Gas Flow
  • Heat Transfer
  • Jet Propulsion
  • Mass Transfer
  • Materials
  • Materials Science
  • Military Research
  • Physical Chemistry
  • Specific Heat
  • Thermal Conductivity

Fields of Study

  • Physics

Readers

  • Combustion science or combustion engineering.
  • Surface Engineering/Surface Coating Technology.