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4884 |
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Tuesday, May 10, 2016, Room 3E 11:50 AM Process Diagnostics, Sensors & Controls |
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Online size measurement of micron-sized in-flight glass particles in APS and SPS processes |
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Ali Akbarnozari* / Concordia University, Canada Shahin Amiri/ Concordia University, Quebec Fadhel Ben-Ettouil/ Concordia University, Quebec Ali Dolatabadi/ Concordia University, Quebec Christian Moreau/ Concordia University, Quebec |
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Plasma spray is a coating method widely used to enhance thermal and mechanical protection of components used in harsh environments, such as turbine blades in jet engines and transmission systems in automobiles. Atmospheric Plasma Spray (APS) is a well-developed coating method using micron size (10 100 µm) powders, while Suspension Plasma Spray (SPS) is an emerging technique using nano- or micron size (0.5 5 µm) powders. The SPS coating characteristics highly depend on the size of the particles immediately before impinging on the substrate surface. The size of these in-flight particles is different from those in the feedstock powders due to particle coalescence in-flight. Online size measurement of the in-flight particles would make it possible to efficiently optimize and eventually control in production coating characteristics. In this paper, the online size measurement is carried out by a laser diffraction method in which the particle size is calculated by measuring the intensity of scattering light, based on the Mie theory. The main objective of this study is to characterize micron-sized in-flight glass particles in the APS and SPS processes by the online method. The glass particles with an average size of 4 µm are injected into the plasma using gas and liquid carriers in the APS and the SPS processes, respectively. The effect of spray parameters, such as the powder mass flow rate, the powder concentration in suspension, and the standoff distance are investigated for both types of injection. This size characterization yields a better understanding of the particles trajectories and the evaporation and agglomeration phenomena in the SPS process. |