With plasma activation, non-reactive or non-wettable surfaces can be modified to obtain better adhesion properties. Many materials can be coated or decorated only after some form of surface activation has been performed. Surface activation by plasma treatment is exceedingly fast, effective, economical, and environmentally friendly.
Surface Activation by Plasma – How It Works
Depending on the material to be treated and the nature of the plasma gas, several mechanisms contribute to the activation effect:
- Plasma activation with argon has a large mechanical effect (“micro-sandblasting”), continuously removing single atoms out of the surface. The remaining radical sites are highly reactive and promote the adhesion of paint or glue.
- With oxygen added to the plasma activation process, polymers receive new surface functionalities which completely reverse the polarity of materials such as polypropylene. After plasma activation, aqueous solutions with high surface tension spread on the activated surface, showing very small contact angles.
- On base metals, surface oxide layers form within minutes. Plasma activation with hydrogen-containing plasma gas reduces superficial oxide layers on electronic parts, which will free the clean, reactive metal surface for bonding and soldering.
Plasma activation has many advantages over traditional wet-chemical activation procedures:
- Grid cut tests show the superiority of plasma surface technology over other forms of surface activation.
- The breakdown of treated materials is minimal, with the purpose of leftover activated parts can be activated a second time.
- The environmental impact of plasma activation is extremely low, since no chemicals are used in the process, and no toxic fumes are formed.
Plasma Activation - Users and Uses
Wherever one layer has to adhere to another layer, plasma activation simplifies production procedures and improves the results. Examples are:
- Aluminum coating – metal surfaces pretreated by plasma activation show a greatly enhanced wettability.
- Precision mechanics, watch, and clock makers – plasma activation makes functional coatings wear-resistant.
- Industrial painting of plastic parts – plasma activation is the most effective way to prepare non-wettable materials for decorating.