An electrically heated metal spray apparatus is provided with a supersonic nozzle. Molten metal is injected into a gas stream flowing through the nozzle under pressure. By varying the pressure of the injected metal, the droplet can be made in various selected sizes with each selected size having a high...http://www.google.co.uk/patents/US5459811?utm_source=gb-gplus-sharePatent US5459811 - Metal spray apparatus with a U-shaped electric inlet gas heater and a one-piece electric heater surrounding a nozzle
