US Patent 7595097 Expanding thermal plasma deposition system

A system to coat a substrate includes a deposition chamber maintained at sub-atmospheric pressure, one or more arrays containing two or more expanding thermal plasma sources associated with the deposition chamber, and at least one injector containing orifices for each array. The substrate is positioned in the deposition chamber and each expanding thermal plasma source produces a plasma jet with a central axis, while the injector injects vaporized reagents into the plasma to form a coating that is deposited on the substrate. The injector orifices are located within a specified distance from the expanding thermal plasma source to obtain generally a coating with generally uniform coating properties.