In PAA-(Pulsed Atmospheric Arc) Technologie®, the generation of a plasma jet is based on the ignition of an electric arc between two electrodes using pulsed high voltage. To stabilize this arc, a vortex is created along the two electrodes by a gas flow, which causes the arc to rotate on the nozzle-shaped cathode. This gas, typically compressed air or nitrogen, which passes close to the arc, is ionized. This creates a plasma flame of highly reactive gaseous species that react with the uppermost atomic layers of the component surface. Depending on the type of gas selected, the majority of these reactive compounds are either
oxygen- or nitrogen-based. When compressed air is used as the process gas, the oxygen content in the plasma leads to the generation of polar end groups on the treated surfaces. This functionalization is even noticeable macroscopically through improved wetting with polar solvents such as water.
Relyon plasma has developed the Piezoelectric Direct Discharge (PDD®) technology for particularly compact plasma generation under atmospheric conditions. This technology is based on direct electrical discharge at an open piezoelectric transformer (PT). This results in a highly effective plasma without significant heat losses. While the plasma generated by the PAA technology® around the arc in the plasma jet is stationary at several hundred degrees Celsius, the temperature of the PDD plasma does not exceed 50°C. Therefore, the latter system usually does not require automation, but can be used as a handheld device for manual plasma treatment.