Passivations are processes with which metal surfaces are made more corrosion resistant through non-metallic protective platings.


Passivation: process and advantages

The parts (e.g. Zn or Zn-Ni – coated steel components) are plated with a protective layer containing Cr (III) during a current-free process. This protective layer is an inorganic passivation layer with a thickness in the nanometers. The precipitation takes place from a Cr (VI)-free solution. The various passivation methods - namely transparent passivation, thick-film passivation, and blue passivation – vary in terms of corrosion protection, optics and colouring. Passivations are most often used on coated steel.Passivation is frequently improved by adding an appropriate seal (top coat). These top coats ensures not only higher corrosion protection but also a more even look of the surface.

Different types of passivations for Zn-Ni coated steel components:

- Transparent passivation: Zn-Ni transcor
- Blue passivation (layer thickness approx. 20-50 nm)
- Thick-film passivation (layer thickness approx. 200-500 nm; better corrosion protection through increased layer thickness) 
For aluminium we also offer processes tailored to the processing of light metals. Contact us.

  1. Increased corrosion protection
  2. Improved adherence properties for downstream coating processes (e.g. finishing) even without thermal storage

Passivations based on CR(III)-containing compounds can replace the cancer-causing chrome coatings containing Cr (VI), which - as a result of legal stipulations (EU used car ordinance, RoHS directive) - may not be used in the automotive industry and many other sectors since 1 July 2007.

  • Automotive and supplier industry
  • Building machinery
  • Consumer (household appliances, designer and luxury items)
  • Electrical appliances
  • Electronics
  • Mechanical engineering
  • Optics
  • Solar technology
  • Packaging industry

Dominik Weil

Phone: +49-2772-5008-590


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