The Plasma Spray process is a high frequency arc that is ignited between an anode (nozzle) and cathode (electrode). The process gases flowing between them are ionized to become a plume of hot plasma gas (12,000°F to 30,000°F). When the coating material is passed through the gas plume, it is melted and propelled towards the substrate forming the coating.
Since the flow of each of the gases and the applied current can be accurately regulated, repeatable and predictable coating results can be obtained.
The distance of the plasma gun from the substrate keeps the part at a controlled spray temperature that is usually in the range of (100°F to 500°F).
FEATURES OF THE PLASMA PROCESS
- Large choice of coating materials, including metals alloys, ceramics, cermets, carbides and others.
- Produces surfaces for a wide variety of applications, including resistance to many different types or wear and corrosion mechanisms, desirable thermal or electrical characteristics, and surface restoration and dimensional control.
- Excellent control of coating thickness and surface characteristics, such as porosity and hardness.
- Low heat affected zone or component distortion.
- High deposition rate.
- High bond strength of the coating to the substrate.
- Coating of complex geometries.
- Masking protection of areas that are not to be coated.
- Process can be fully automated utilizing robotic equipment.
- Coating of some internal bores possible.