German parts specialist MELYE has highlighted the benefits of the zinc flake coating on it control arm suitable for the Golf 7. 

The rear, lower control arm on the Golf 7 is open at the top. This means that dirt and water can get to the spring’s seat at all times and water can enter through cracks in the finish. As a result, the drainage holes get clogged up, preventing the water from draining away fully. In addition, if the finish is damaged by stone impacts, the material underneath can rust so badly over time that the spring penetrates the control arm. 

In a case like this, the safety of the vehicle is no longer guaranteed and continued use of the vehicle is not advisable.   

The spring-carrying control arm is highly susceptible to corrosion as it is exposed to various external influences. These include: 

• 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 can cause NCT failure meaning good protection is vital. 

The distinction is made 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. 

In addition to the standard galvanic coating procedure, there are also so-called zinc flake coatings available. 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. Zinc flake coatings also 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. 

Zinc flake coatings offer effective protection against corrosion and significantly lengthen the service life of control arms.

The MEYLE control arm with its zinc flake coating for the Golf 7 is part No. 116 050 0236/HD.