Applications:
Used primarily on aluminium components in aerospace, electronics, defence, automotive and general manufacturing. It serves as a corrosion-resistant conversion coating and/or as a primer base for paint or powder coat.
Advantages:
Very thin coating so minimal dimensional change.
Provides good corrosion protection while maintaining electrical conductivity when needed.
Improves adhesion for subsequent finishes (paint, powder).
Appearance:
Varies depending on the specific product: typical colours range from clear/light yellow through iridescent gold/tan on aluminium.
Applicable Materials:
Primarily aluminium and aluminium alloys. Some conversion coatings may work on zinc, cadmium, magnesium, but aluminium is the major substrate.
Important Notes:
Because the coating is so thin, cleaning and pretreatment are extremely important: poor cleaning leads to patches, incomplete conversion films.
While the coating adds corrosion protection, it is not typically suited for high-wear surfaces; if heavy abrasion or wear is expected, additional treatments may be required.
Some formulations contain hexavalent chromium; environmental/health regulations may limit those and alternatives (e.g., trivalent conversion coatings) exist.
Because the film is thin (~0.25-1 µm for many aluminium conversion coatings) it doesn’t significantly alter tolerances.
Thermal limits apply: in one study, Class III Alodine’s conductivity was compromised above ~140 °F (~60 °C) exposure.
