Abstract:
The overall aim of this research project was to design and construct an inhouse,
thermal chemical vapour deposition (CVD) reactor system,
operating at atmospheric pressure. Radio frequency (RF) induction
heating was used as the energy source, with a vertical-flow design, using
thermally stable materials. The steps in the design and construction of this
CVD system are described in detail. The growth conditions at different
substrate temperatures, gas flow ratios and substrate-gas inlet gaps were
assessed as part of the project. The growth rate of ZrC layers increases
with increasing substrate temperature. The microstructure properties of
the ZrC layers such as lattice parameters and orientation of crystal planes
were all found to be dependent on deposition temperature. The increase in
free carbon in the as-deposited coatings as the temperature increased was
found to be a stumbling block for obtaining stoichiometric ZrC coatings.
The surface morphology of the as-deposited ZrC layers also depends on the
deposition parameters.
