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Materials that protect
against erosion, wear, oxidation, and other harmful
degradation are of great interest for various industries, including
coatings for automotive engine parts and for cutting tools for machining.
Such materials must display high hardness, wear resistance, chemical
stability and oxidation resistance above 1000 C, and have a high thermal
conductivity and low friction coefficient with the contact material.
With these characteristics, the use of such materials as coatings would
reduce and possibly eliminate the necessity of costly and hazardous
coolants. Nanostructured composite coatings offer the possibility of
obtaining these materials characteristics.
A triple torch thermal
plasma system is used in a thermal plasma chemical
vapor deposition (TPCVD) process to synthesize the Si-C-N films. This
process offers the possible use of versatile multiphase reactants, a
controllable film structure, and high growth rates.
The Si-C-N nanostructured
coatings are characterized for their structure,
morphology, and mechanical properties. Techniques include Fourier
transform infrared spectroscopy (FTIR), micro x-ray diffraction (XRD),
optical and scanning electron microscopy (SEM), and indentation.
Finally, the thermodynamics
and kinetics of the deposition process are
examined to understand the mechanisms leading to a superhard
nanostructured composites in the ternary Si-C-N system. This
investigation assists in giving an indication of how to improve the
mechanical properties of the coatings.
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