Suspension plasma spraying for coatings and powders nanoarchitecture. - La projection par plasma de suspensions pour la nanoarchitecture des revêtements et des poudres.

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Thermal spraying is a multi billion dollars activity in North-America. Most of the issues with thermal spraying are to provide to existing materials a localized benefit in terms of higher hardness, superior heat, corrosion resistance, wear or sliding performance.*******All the coatings have to be engineered to survive to a very hostile or demanding environment and need always to be improved to save weight, costs and to decrease the maintenance costs. As the substrate materials quality are progressing with the research invested by the aerospace and automotive industry, so must also the coatings being further developed. Nanostructured coatings brought a whole new application potential in those fields and are showing promising results in the field of energy and sensors.****The principal investigator has developed the suspension plasma technology 20 years ago and this technology is finding its way in the industry. The benefits of this technology are numerous: it allows the safe handling and injection of nanomaterials in a DC or a RF Plasma, it allows a unique flexibility in composition which is recognised by its wide use among the scientific community in governmental research laboratories or universities around the world. Moreover there are two Canadian companies which are manufacturing and selling the suspension plasma technology applied to DC and Induction plasma. However in the industry there are resistances related to the adoption of this technology. Mostly, the process efficiency in terms of kg of materials / kWh is questioned as for a large scale application, the power consumption becomes one of the biggest cost. The quality and reproductibility of the process is also questioned as the standard probes are subjected to a strong erosion due to the material loaded with hard ceramics which are playing the role of a saw for the probes. As a result, in order to improve the overall process it is proposed to resolve some of those issues and propose interesting innovations for the thermal plasma community. The general objective of the proposed research is to enhance the efficiency of the thermal plasma suspension plasma processing of materials****The specific research objectives are to:****-A- Improve the injection of the suspension****-B- Improve the SPS plasma material energy transfer and available energy density****-C- Improve the residence time of the materials in the plasma****-D- Develop the combinatorial synthesis of nanopowders.*******The proposed methodology will include changes in the geometry, spatial distribution and use of multiple injectors (A), heat and mass transfer concepts in plasma conditions will also be needed for (B) and plasma chemistry will be used for (B) and (C) and plasma engineering will be used for (C) and (D).***