NOZZLE FOR THERMAL SPRAY OF LOW OXIDE CONTENT COATINGS

摘要

The present invention provides a spray gun (10) with associated nozzle attachments for high deposition efficiency for thermal spray of high quality , dense, low oxide content coatings. The spray guns (10) are used to produce coatings using a thermal spray process, a high velocity oxy-fuel process, a high velocity air-fuel process, cold spraying, and plasma spraying in which the process is characterised by having an over-expanded flow with a Mach number from about 1.0 to about 4.0 which have passageway (28) section which diverges to the gun outlet. In one embodiment the nozzle attachment is anoth er diverging section (24) with a greater angle of divergence than the diverging nozzle section. In another embodiment the nozzle attachment includes the aforementioned diverging nozzle attachment section followed by a converging nozzle section (42) having an outlet section through which the thermal spray is emitted.