Plasma spraying

Coating process by means of plasma not based on plasma polymerisation. Since plasma spraying can be done at atmospheric pressure, it is fit for inline use and thus suitable also for treating very large areas. The plasma is generated in a gas jet by corona discharge. The coating material is injected in the form of a fine powder into the gas jet where it melts immediately because of the high plasma temperature. With the plasma jet, the melted powder is shot onto the substrate where it hardens instantly. Argon, helium, nitrogen or hydrogen are used as plasma gases. To completely avoid any oxidation of the coating material by air oxygen, plasma spraying can also be done in a vacuum chamber (⇒ Vacuum plasma spraying).