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

热喷涂在北美是一项价值数十亿美元的活动。热喷涂的大多数问题是在更高的硬度、更好的耐热性、耐腐蚀性、耐磨性或滑动性能方面为现有材料提供局部好处。所有涂层都必须经过设计，以在非常恶劣或苛刻的环境中生存，并需要始终进行改进，以节省重量、成本和降低维护成本。随着航空航天和汽车工业的投入，基材质量不断提高，涂层的进一步发展也势在必行。纳米结构涂层在这些领域带来了全新的应用潜力，并在能源和传感器领域显示出良好的结果。*首席研究人员早在20年前就开发了悬浮等离子体技术，该技术正在该行业找到自己的方向。这项技术的好处有很多：它允许在直流或射频等离子体中安全地处理和注入纳米材料，它允许独特的组成灵活性，这一点得到了世界各地政府研究实验室或大学的科学界的广泛使用的认可。此外，还有两家加拿大公司正在制造和销售应用于直流和感应等离子体的悬浮等离子体技术。然而，在该行业中，采用这项技术存在阻力。大多数情况下，以千克材料/千瓦时为单位的工艺效率受到质疑，因为对于大规模应用，电力消耗成为最大的成本之一。该工艺的质量和重复性也受到了质疑，因为标准探头由于装载了硬质陶瓷的材料而受到强烈侵蚀，硬质陶瓷起到了探头的锯子作用。因此，为了改进整个过程，建议解决其中的一些问题，并为热等离子体社区提出有趣的创新。拟议研究的总体目标是提高热等离子体悬浮等离子体处理材料的效率*具体研究目标是：*-改进悬浮液的注入*-B-改善SPS等离子体材料的能量传递和可用能量密度*-C-改善材料在等离子体中的停留时间*-D-发展纳米粉末的组合合成。*建议的方法将包括改变多个喷射器的几何形状、空间分布和使用，(B)还需要等离子体条件下的传热和传质概念，(B)和(C)将使用等离子体化学，(C)和(D)将使用等离子体工程。*

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).***