Sectors where plasma spraying is used include the aerospace industry (e.g. turbine blades and inlet surfaces), medical (implants) and insulating coatings.
In plasma spraying, the powdered spray additive in or outside the spray gun is melted by a plasma jet and sprayed onto the surface of the workpiece. The plasma is generated by an arc, which burns in argon, helium, nitrogen, hydrogen or mixtures thereof. When this happens, the gases are dissociated and ionized. They reach high outflow velocities, and transfer their heat energy during recombination to the spray particles.
The arc is non-transmitting, i.e. it burns inside the spray gun between a centrally positioned electrode (cathode) and water-cooled nozzle forming the anode. This method is used in a normal atmosphere.