The plasma spray process uses plasma (hot ionized gas) to melt the
powder and propel it onto the substrate through the expanding plasma gas.
Nitrogen or argon serves as the primary plasma forming gas. A secondary
gas of either hydrogen or helium increases the heat content and velocity of
the plasma. The plasma-arc created between a coaxially aligned tungsten
cathode and an orifice (nozzle) in a copper anode operates on direct
current from a rectifier-type power supply. A central control unit regulates
electric power, plasma gas flow and cooling water, and sequences these
parameters to initiate the process with precision and reliability. The type
of nozzle, arc current, ratio of the primary and secondary gases, and the
gas flow rate control the heat content, temperature, and velocity of the
plasma stream. Plasma systems provide controllable temperatures that
exceed the melting range of any known substance.

Coating Features:

• Plasma spray coatings offer the greatest variety of coatings due to the high temperature range of plasma spray guns.