Interior view of car


Components in the interior of vehicles are not exposed to corrosive stresses to such an extent. It is important in this area to ensure the functionality of parts that are in use on a daily basis.

Exemplary components

 Belt buckleSpiral / Torsion springsClipsCompression springs

The belt buckle serves to receive and secure the safety belt system. As a safety-relevant component, they need to display good sliding properties to ensure no malfunctions when in use.

Spiral and torsion springs are so-called retention springs that are fitted to all fold-down rear seats. They ensure that the seat can be easily tipped back into the initial position after folding. Possible squeaking needs to be avoided to prevent quality issues from arising.

Clips are used in numerous areas to secure cable routing. They are frequently produced from high-tensile spring steel and are subject to a wide range of requirements such as sliding properties, to enable easy movement of cables. In contrast, other surfaces with a high static friction have a high pull-out strength that keeps the components together.

To counteract the weight force when using vehicle flaps, pretensioned helical compression springs are used in automotive construction. Due to their length-to-diameter ratio, these are not resistant to buckling. Signs of wear, including corrosion and spring fractures, must be effectively prevented.



  • Corrosion protection (96 h as per DIN EN ISO 9227)
  • Colouring (black)
  • Sliding properties (0.06 – 0.3 µtot)
  • Coefficients of friction
  • Compatibility with microencapsulation


Depending on the components to be coated, DÖRKEN offers a wide range of micro layer corrosion protection systems. Where there are low requirements of corrosion protection a topcoat coating with specific functional characteristics such as glide or friction properties is often suitable. For other components special systems consisting of a zinc flake base coat and a topcoat can be applied, depending on the parts concerned. The very thin coats are annealed at comparatively low temperatures. No hydrogen is generated in the coating process, with the result that no application-related, hydrogen-induced stress corrosion cracking occurs. A further advantage of the zinc flake systems is dry lubrication. The dry lubricating film generated by the application displays excellent friction and wear characteristics and ensures good grip properties.