Speaker
Description
Carbon nanostructures and specifically nanotubes (CNTs) are materials of significant importance in nanotechnology. They have a wide range of applications ranging from automotive to aeronautics, due to their exceptional mechanical properties such as strength and stiffness-to-density/weight ratio. The synthesis of CNTs includes a variety of methods amongst which the chemical vapor deposition (CVD) is the more attractive, since it can be used for their large-scale production with moderate cost. CVD is an extending technology used for growing thin films and coatings on surfaces, often complex-in-shape. In CNTs production, CVD provides the possibility of controlling the structure of the produced materials and as a consequence their properties. For this reason, it is necessary to control the complex chemistry reactions and transport mechanisms involved in a CVD process.
In this work, a combined experimental and computational investigation is conducted for the growth of CNTs on silicon wafers and carbon fibers fabrics by CVD, with supported and floating catalyst, respectively. The phenomena occurring at the macroscopic level are governed by the conservation equations of mass, momentum and energy combined with the kinetics of the gas phase and surface chemical reactions. The analysis provides information for the flow field and the dominant reaction mechanisms and it reproduces the experimental data successfully in terms of the produced CNTs mass. It also provides valuable information for CNTs properties, such as the termination length and it illustrates their dependence on the process temperature and flow conditions. The presented computational investigation combined with targeted experiments provides an integrated tool for the understanding of the phenomena occurring at the macro-scale of a CVD reactor promoting the optimal design and the upscaling of the process.
Acknowledgements
This study was funded by the Horizon 2020 Project “SMARTFAN», under G.A. 760779.
| Speaker Country | Greece |
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