Powder coating
Another method of coating materials that can be used to protect various types of metals is powder coating.
Powder coating is a popular way of coating various types of surfaces. During painting a special powder paint is used, which is evenly distributed on the surface of the material to be coated. There are two types of powder coating: electrostatic or electrokinetic spraying. The coating obtained in this way is not only very smooth and durable. It is also distinguished by its excellent technological parameters. The powder coating technique is mainly used for coating metals.
The tools used in this method are spray guns.
Electrostatic powder coating
Devices are used that produce the effect of charging paint particles. The painted surface “attracts” its particles when an electrostatic field is created. During painting, the paint particles are charged negatively. This is possible because a constant voltage and a constant current runs through the system. The particles of the painted surface are positively charged, so an electrostatic field is created when spraying. The paint particles are thus attracted to the surface and adhere evenly to it.
Electrokinetic powder coating
It is a method commonly called tribo and it runs differently. The paint particles are electrostatically charged by compressed air. Their charging process is based on kinetic energy and the charge is carried before the paint particles. In this case, friction is responsible for a positive charge of the paint particles. The particles rub against each other, against the inner walls of the application line or against the inner walls of the applicator. Powder paint particles collide with the painted surface and adhere to it.
The most important advantages of powder coating:
- no emission of solvents and thinners to the environment,
- almost 100% use of the painting material (possibility of recovering the unplanted powder particles),
- significant energy savings due to the possibility of using closed ventilation systems,
- coatings thanks to their thickness (60-80 μm) well mask the surface of the part,
- corrosion protection of coated materials.
