Materials E-Guide
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The atmospheric plasma spray process is used for wear and corrosion protection, thermal insulation, repair, restoration and further surface functions. As it is the most flexible of all thermal spray processes, coatings can be applied at high deposition rates onto different metallic substrates by using the widest variety of powder feedstock materials composed of metals, alloys, carbides, ceramics and others. As such, atmospheric plasma spray is often used to apply coatings for thermal protection, wear resistance, corrosion control, dimensional control and restoration and much, much more.
Key benefits of this process
- Most flexible of all the thermal spray processes, with sufficient energy to melt any material — even materials with high melting points such as ceramics.
- Excellent control of coating thickness and surface characteristics such as porosity and hardness
- Widely used for high-volume production
Typical applications
- Gas turbine components
- Textile and printing machinery
- Automotive cylinder liners
- Medical implants
Process description
A strong electric arc is generated between a positively charged pole (anode) and a negatively charged pole (cathode). This ionizes the flowing process gasses into the plasma state. The powder feedstock material is injected into the plasma jet, melting the powder particles and propelling them onto the workpiece surface.
In addition to conventional atmospheric plasma spray guns, Oerlikon Metco has pioneered cascading arc plasma spray guns. Cascading arc spray guns constrain the arc between the anode and cathode, resulting in a more controlled spray plume. In turn, this results in more homogeneous heating of the plasma particles, and significantly increases the possible spray throughput (measured as deposit efficiency times spray rate). The resulting coatings are more reliable and can be applied faster.
Process basics
- Heat source: arc
- Feedstock: powder (ceramics, metals, alloys, blends, carbides and others)
- Plasma temperature: approx. 16 000 °C (28 800 °F)
- Particle velocity: up to 450 m/s (1 500 ft/s)
- Approximate application rate: 4 to 8 kg/h (9 to 18 lb/h)
