Abstract: A nozzle assembly for a plasma gun is disclosed, containing an annular coolant passage for extended nozzle life, providing for convenient and low cost replacement of the nozzle member and for improved gun operation. To form the assembly a jacket is disposed about the nozzle member in a predetermined coaxial position. An inner surface of the jacket cooperates with the cylindrical exteriority of the nozzle to define an annular coolant passage. The jacket and the nozzle are in relative slidable relationship such that the nozzle member is removable and replaceable forwardly with respect to the jacket, forwardly being in respect to the direction of the plasma flame. A flange at the forward end of the nozzle member retains the nozzle member from sliding rearward from the predetermined position with respect to the jacket. The jacket has coolant ports for the coolant connecting with the annular passage. A seal such as an O-ring is interposed between the rear portion of the nozzle and the jacket.

Abstract: A plasma flame spray gun suitable for being constructed physically smaller than comparable power prior art plasma flame spray guns. The gun includes a nozzle having a tapering portion on the inlet side thereof. A cathode with a flat tip is positioned to at least partially extend into the tapering portion of the nozzle. A gas distribution ring is located around the cathode for creating a vortex around the cathode tip. This causes the arc formed between the tip and the nozzle to have a root which spins around the perimeter of the nozzle tip resulting in less wear and, therefore, extended part life.

Abstract: A plasma spray gun system with improved nozzle life. The gun includes a nozzle with a thin annular coolant passage and having a dimension optimized for nozzle life. The system also includes a deionizer to remove ions from the cooling fluid and a dissolved gas remover which also improves nozzle life. In addition, the coolant is treated to remove ions which extends nozzle life even more. Further cooling fluid treatment for even further nozzle life includes dissolved gas removal and heat removal.

Abstract: A plasma spray gun nozzle with a thin annular coolant passage having extended life. The thin annular passage is located adjacent a thin nozzle wall which confines the arc formed in the nozzle. The dimensions of the thin annular passage and the wall thickness are selected to assure maximum nozzle life.

Abstract: Method and apparatus for plasma flame-spraying coating material onto a substrate by means of passing a plasma-forming gas through a nozzle electrode, passing an arc-forming current between said nozzle electrode and a rear electrode to form a plasma effluent, introducing spray coating material into the plasma effluent, passing the plasma effluent axially through a wall shroud extending from the exit of said nozzle electrode and forming a hot gas shroud for the plasma effluent at least within the wall shroud.

Abstract: Method and apparatus for plasma flame-spraying coating material onto a substrate by means of passing a plasma-forming gas through a nozzle electrode, passing an arc-forming current between said nozzle electrode and a rear electrode to form a plasma effluent, introducing coating material into the plasma effluent, passing the plasma effluent axially through a wall shroud extending from the exit of said nozzle electrode and forming a flame shroud for the plasma effluent at least within the wall shroud.

Abstract: Method and apparatus for plasma flame-spraying coating material onto a substrate by means of passing a plasma-forming gas through a nozzle electrode, passing an arc-forming current between said nozzle electrode and a rear electrode to form a plasma effluent, introducing spray coating material into the plasma effluent, passing the plasma effluent axially through a wall shroud extending from the exit of said nozzle electrode and forming a hot gas shroud for the plasma effluent at least within the wall shroud. .Iadd.