Zinc flake coatings: the anti-corrosion solution?
Why are control arms so susceptible to corrosion?
The spring-carrying control arm is highly susceptible to corrosion as it is exposed to various external influences:
- Mechanical stress: An accumulation of sand and dirt at the spring seat leads to a higher degree of wear of the protective layer and thereby premature wear and tear.
- Stone impacts: The direct contact with the road surface damages the coating, allowing moisture to find its way in.
- Moisture: Water penetration under the paint layer causes infiltration and detachment, which in extreme cases can lead to spring breakage.
⚙️ These problems are regular causes of complaint by testing institutions such as TÜV and often lead to the rejection of rusted control arms.
Principles of protection against corrosion
Good protection against corrosion is vital for spare parts, which are exposed to severe environmental stress.
The distinction is made here between passive and active corrosion protection.
Passive corrosion protection is achieved through a coating, such as conventional paint. This forms a barrier between the metal and the environment. But only as long as the coating remains undamaged.
With active corrosion protection, on the other hand, chemical processes come into play which minimise corrosion. A well-known procedure is the cathodic protective effect, whereby the metal itself is protected against corrosion and no additional barrier, such as paint, for example, is used.
❗ It is important to mention that not every material is suitable for active corrosion protection!
Not all coatings are alike
In addition to the standard galvanic coating procedure, there are also so-called zinc flake coatings available today. In this process, zinc particles in the form of flakes are used, which adhere to the metal surface thanks to special bonding agents.
💡 This means that it is active protection!
The zinc flakes act as pigments or layers that not only passively protect the steel beneath by acting as a barrier, but also actively, as the zinc oxidises preferentially, thereby protecting the steel from corrosion.
Furthermore, zinc flake coatings have a high temperature resistance, which creates a resistant and robust protective layer. As a result, control arms with this coating can withstand a high level of mechanical stress.
💡 Incidentally, corrosion resistance is tested in so-called ‘salt spray chambers’.
To summarise, zinc flake coatings offer effective protection against corrosion and significantly lengthen the service life of control arms.
