5.4.3 Etching of metals
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).
Etching is in principle suitable for all uncoated metals.
- 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