Plasma cleaning & plasma surface modification
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What is plasma?
Plasma is a reactive gas that consists of energy rich electrons, ions and neutral particles.
Definition: plasma (Greek for malleable) After the aggregate states for matter, Solid, fluid and gas comes plasma often known as 4th aggregate state.
Low pressure plasma
Cold plasma is generated under low pressure ‹100 Pa (1mbar) in a vacuum chamber.
By the application of an electromagnetic field the gas or gas mixture present in the chamber is ionized and so brought into the highly reactive form known as plasma.
The surfaces of the parts in the plasma chamber dependent on the choice of gas or gas mixture (air, Nitrogen, Oxygen etc.)
and type of energy coupling [DC, kHz, MHz (Radio frequency) or GHz (Microwave)] are deliberately modified.
In low pressure plasma surfaces can be:
The following video only has German tone at the moment, but the 3 D animations show clearly the effect of plasma at work.
- Fine cleaned
- Function of plasma
- The first example shows that the effects are independent of form.
- The first 3D animation shows the micro sand blasting effect know as Sputtering.
- The second the removal of contamination by chemical reaction with the reactive gas in the plasma.
- The third shows the destruction of carbon chains due to UV light.
- The forth, Polymerizing and coating of a surface.
The finest cleaning of metal parts is an important process for low pressure plasma.
The contamination is removed by a chemical reaction with the ionized gas, transferred into the gas phase and then pumped out of the chamber.
The surface is the cleaned residue free ready for the next process.
Plasma cleaning of metal.
Plasma activation alters the functional groups on the surface of the material being treated improving adhesion of the paint or adhesive system.
The reactive species in the plasma structure the surface by removing part of the surface.
The creates a pore like microstructure offering an improved adhesion due to the increased are for adhesion.
In plasma coating a polymer coating is laid down on the surface of the work piece. The introduced process gas determines the layer characteristics.
The deposited layers can be either hydrophobic, hydrophilic, a decorative or protective (anti scratch or anti fog) layer.
Functional layers to further enhance adhesion (plasma primer) between the treated parts and a paint or adhesive coat.