5.4.3 Etching of metals

Objective:

Etching is a wet-chemical method that is used to remove the uppermost layers of substrates. In some cases it leads to formation of a new, defined surface layer that serves to provide corrosion protection (chromation, phosphatisation).

Suitability:

Etching is in principle suitable for all uncoated metals.

Procedure:

  • Prior to etching the surface must always be thoroughly cleaned and degreased.
  • Check the etching bath (substrate-specific formulations/procedures)
  • Application by brush/roller or by immersion in an etching bath; monitor the etching parameters (bath composition, temperature and duration of the treatment)
  • After etching thoroughly rinse the substrates with water; carry out the last rinsing step with demineralised water; then dry the substrates and immediately start the bonding process

Points to heed:

  • Clean the substrates beforehand
  • Check the etching bath regularly
  • Monitor the etching parameters
  • The etching bath parameters must be adapted to the substrate material