High Velocity Pulsed Plasma Thermal Spray

The quality and durability of coatings produced by virtually all thermal spray techniques could be improved by, among other things, increasing the velocity with which coatings particles impact the coated surface and by better control of the chemical and thermal environment seen by the particles during flight. A new and innovative approach to thermal spraying is proposed that can increase coating particle velocities at least a factor of two to the 2000-2500 m/sec range. These higher coating particle velocities and improved control of the particle chemical and thermal environment during flight are expected to lead to dramatic improvements in coating quality. The process deliberately uses a repetitively pulsed, high temperature plasma jet. Such jets can be used in a variety of ways to melt and accelerate coating materials. In Phase I we propose to develop a computational model and an engineering design of a prototype pulsed plasma jet spray device. Successful development of this sprayer is expected to open up new markets for thermal spray applications and to improve the performance and durability of hypervelocity gun launch components and high temperature rocket components, and industrial applications where traditional spray is limited. Superior quality thermal sprayed ceramic and refractory metal coatings that are denser, harder, more uniform, lower porosity, and higher adhesion and cohesion. Potential commercial applications include advanced coatings for gas turbines, internal combustion engines, rocket components, load-bearing surfaces for heavy equipment, and ceramic substrates for electronics.