Advanced diagnostics and controls of thermal spray coating processes

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Thermal spray is one of the most used coating technologies with applications in several industrial sectors such as aerospace, automotive, biomedical, energy, etc. The technology is versatile as metals, ceramics, polymers and their composites can be sprayed to produce high-performance coatings/films. The deposition processes involve spraying on a substrate molten or semi-molten particles (droplets) that flatten, solidify and accumulate forming a coating presenting a very typical lamellar structure. The study of the relationships (process maps) between the spray parameters and in-flight particle characteristics and between in-flight particle characteristics and actual coating properties brings the data necessary to better control the spray processes and design efficiently high performance coatings.**The proposed program targets the development of diagnostic and modeling tools that will permit us to tailor coating properties based on a more fundamental understanding of the complex transformation/transfer processes occurring during spraying. An important focus will be given to the emerging technology of suspension thermal spray (STS). This process enables spraying nano- or submicron powders by suspending them in a liquid carrier (commonly ethanol or water). This allows the deposition of coatings with unique microstructures that are one to two orders of magnitude finer than those normally generated in conventional thermal spray processes. These nano-scale structures bring new and improved properties of the deposited coatings that are sought in demanding applications. The emerging STS process has the potential of replacing much more expensive PVD/CVD processes as it does not require expensive vacuum systems and allows deposition on large components. To achieve this vision although, it is necessary to better understand and control coating structure and properties.**The research outcomes of this DG will contribute to develop a comprehensive understanding of thermal spray processes and, more particularly, of the emerging STS process. This new knowledge will stimulate the growth of thermal spray markets in Canada by training HQP and by developing and deploying advanced coating and sensing technologies in key industrial sectors for Canada; that is to say; aerospace, energy and natural resources. The trained HQP will gain experience and technical expertise in advanced manufacturing, an industrial sector of fundamental importance to the Canadian economy. The developed diagnostic techniques and models are crucial as they will be extensively used for developing innovative STS applications in the more applied research themes we want to address in our newly establish Canada Research Chair in Thermal Spray and Surface Engineering. Indeed, we will use extensively these tools to optimize and control coating characteristics in emerging STS applications such as thermal barrier coatings, fuel cells, sensors, functional coatings, active membranes, etc.