"Online Measurement of Size Distribution of In-flight Particles in the Suspension Plasma Spray Process"
A. Akbar Nozari, A. Dolatabadi, C. Moreau
Suspension Plasma Spray (SPS) is an emerging field of thermal spray in which submicron ceramic powders are put in suspension in a liquid and injected in the plasma. It produces nanostructured layers on a substrate with unique characteristics. The diameter of the in-flight particles is among the most important parameters which determines the final coating properties. Therefore, online monitoring of diameter would make it possible to achieve a better control of the SPS coating deposition. However, harsh plasma booth environment, small size of the particles with high velocity and temperature make these measurements challenging. We will discuss the potential use of different optical approaches for SPS particle size measurement based on light scattering and imaging techniques. Each approach suffers from some limitations which may lead to significant errors in the measurements. Finally, some comments will be given about advantages and disadvantages of these particle sizing techniques in SPS applications.