Diagnostics and control in the thermal spray process

The plasma-spray process features complex plasma-particle interactions that can result in process variations that limit process repeatability and coat ing performance. This paper reports our work on the development of real-tim e diagnostics and control for the plasma spray process. The strategy is to directly monitor and control those degrees of freedom of the process that a re observable, controllable and affect resulting coating properties. This i ncludes monitoring of particle velocity and temperature as well as the shap e and trajectory of the spray pattern. Diagnostics that have been developed specifically for this purpose are described along with the demonstration o f a closed loop process controller based on these measurements, (C) 2001 El sevier Science B.V. All rights reserved.