ABSTRACT
A variety of thermal spray processes are available to deposit thick coatings for a broad range of applications [1-3]. The processes are essentially similar in that a material is heated up by a gaseous medium and simultaneously accelerated and projected onto the substrate. The family of thermal spray processes includes, among other processes, flame spraying, plasma spraying, vacuum plasma spraying (also called low pressure plasma spraying), high velocity oxygen fuel, arc metallization, and detonation gun spraying. The prime distinctions between these spraying processes are the temperature of the process and the velocity of the thermal source used in the process. These process variables control the nature of the materials that can be sprayed. The techniques also differ with regard to their process economics; that is, factors such as the cost of the equipment, the cost of
measuring the adhesion strength' of thermally sprayed coatings. A strong intent is to always relate such measurements to the ultimate application(s) of the coatings.
