Zinc flake systems from Dörken MKS:
wafer-thin high performance protection
Zinc flake serves a highly-specialised niche market. Its efficient function means that it fulfils the specific requirements of this niche so perfectly that it is used in numerous areas in which corrosion protection plays a key role. Whether it is the automotive sector, construction machines or wind energy: the leading industries have relied on zinc flake technology for over 30 years. This process plays to its strengths in the processing of small bulk parts such as screws, clips and spring band clips – with extremely low coat thickness and high durability. It is also increasingly used on large parts with extensive surface areas, such as rear subframes or struts.
Minimal coat thickness
This superbly thin characteristic in particular plays a key role in the success of zinc flake: the overall coat thickness is an average of just 8–12 µm – thinner than a human hair. This makes the zinc flake almost invisible in comparison to standard corrosion protection systems such as powder coating or hot dip galvanisation. Nonetheless, it easily achieves a protective effect of several thousand hours against base metal corrosion in neutral salt spray testing as per DIN EN ISO 9227. Numerous approvals confirm this effect.
The function of the zinc flake coating can be explained as a “lacquer” consisting of numerous small flakes. The coating is typically a combination of zinc and aluminium lamella (as per DIN EN ISO 10683 or DIN EN 13858), bound together via an inorganic matrix. Zinc flakes offer cathodic protection, because the sacrificial effect of the zinc means that the component is actively protected against environmental influences.
A zinc flake coating comprises a basecoat and a topcoat. Together, these are referred to as the “system”. The combination of different base and topcoats enables a system to be set to individual requirements, for example a specific coefficient of friction or specific chemical resistance.
High fitting accuracy
The benefits of zinc flake extend far beyond mere corrosion protection. Its thin properties make it ideally suited for components that require high fitting accuracy – such as bolts or screws with metric threads.
No stress corrosion cracking
As no hydrogen is involved in the application process, there is no risk of application-related hydrogen-induced stress corrosion cracking. This means it is also particularly well-suited for high-tensile steels of the classes 10.9 and 12.9 or from 1,000 MPa.