Laser Based Particle Visualization instruments such as SprayCam provide a unique picture into the radial injection of powders in APS processes. Traditional injection optimization methods utilizing these instruments involve optimization of particle temperature and velocity while measuring the particle plume position in the plasma. The goal of these optimization techniques is to ensure maximum energy transfer to materials with a high melting point and a low thermal conductivity, such as is typical for materials applied as thermal barrier coatings. Conversely, optimizing energy transfer of composite powders with a low melting point and a high thermal conductivity, such as Al-8Si-20BN, has very little effect, thus it is difficult to optimize the injection process of this material in the traditional fashion. In addition, these materials have a tendency to bounce off the plasma rather than penetrate it due to their low inertia, resulting in low deposition efficiencies. A new method of injection optimization of these powders is proposed utilizing Laser Based Particle Visualization Techniques to view the injection from above in order to maximize powder injection into the plasma. A real-time examination of particle plume width inside the plasma will be conducted, varying an array of torch conditions while deposition efficiency is monitored.

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