Measurement of Particle Parameters in Thermal Spray Systems

Abstract

Particle parameters are important in the optimization of plasma and flame spray processes that involve fine powders. Such processes include plasma and flame spraying, spheroidizing, and chemical processes in which the material is introduced in the form of fine powders or the final product is in the form of a fine powder, e.g. plasma synthesis of ceramics. To fully characterize the particle flow field, it is necessary to measure the particle size, velocity, and number density. In many cases, it is necessary to measure simultaneously several parameters that are strongly coupled such as particle size and temperature, or size and velocity. In this paper we will describe a laser based measurement technique for simultaneously obtaining the in-flight size, velocity, and temperature of small particles entrained in a flow field.

Plasma Spray Deposition: A Need for Direct Process Control

“…Direct measurements of partide temperatures have been made using spectroscopy and laser techniques. Laser doppler, laser fluorescence and optical high sIJeed anel/or streak photography have been employed for measuring particulate velocities118, 19,20]. These techniques are non-intrusive and could be used continuously during processing.…”