Chromate conversion coating is an economical finish for aluminum corrosion resistance or to retain electrical conductivity alone, as a pre-treatment for paint or adhesive, or as a post-treatment coating on other plating finishes.
Type I - Compositions containing hexavalent chromium
Type II - Compositions containing no hexavalent chromium
Class 1A - Corrosion prevention unpainted, or improve adhesion of painted finishes
Class 3 - Protection against corrosion where low electrical resistance is required
|ASTM B449-93 (re-approved 2015)||
KEY: Class, Appearance, Coating mass per unit area g/m2, corrosion protection
1 – yellow to brown, 0.4 to 2, Maximum corrosion resistance typically as final finish
2 – colorless to yellow, 0.1 to 0.4, medium corrosion resistance, base for paint and adhering to rubber
3 – colorless, less than 0.1, decorative, light corrosion resistance, low electrical resistance
4 – light green to green, 0.2 to 5, medium corrosion resistance, base for paint and adhering to rubber
|ASTM-B921-08 (reapproved 2013)||
1 – Maximum corrosion protection typically as a final finish
2 – Medium corrosion resistance, base for paint and adhering to rubber
3 – Light corrosion resistance, low electrical resistance
4 – Medium corrosion resistance, base for paint and adhering to rubber
- Corrosion testing according to ASTM B117 can be provided by request.
- RoHS compliant and non-RoHS compliant chemical conversion coatings available.
- Detailed metal masking solutions are available to ensure that finishes are applied precisely.