Characterization of plasma sprayed deposits : influence of process parameters

Abstract

The plasma spray technique is a highly sophisticated and effective surface treatment that has been successively used to produce protective coatings to improve component's resistance to corrosion, wear or heat in many industrial applications. Due to an increasing field of applications, along with more severe demands on coating properties, a remarkable change in the research concept of the plasma spray process has been noted. Previously, coatings of proper material properties were deposited and fulfillment of particular application requirements was examined. Recently, the individual stages of the plasma spray deposition process have been studied separately in order to establish the influence of main controlling parameters on the process; e.g., plasma formation, particle in-flight velocity and temperature, splat formation, coating properties, etc. Most of efforts were dedicated to study the electric arc fluctuations inside the plasma torch and their influence on formation of the plasma jet, the splat formation and change in the splat morphology. This led to the development of new plasma spray torches, diagnostic techniques and also advanced 3-D models.