Alodine Overview
Alodine is a chemical conversion coating used primarily on aluminum and its alloys. A reaction between the coating solution and the part surface forms a thin protective film that improves corrosion resistance and paint adhesion while maintaining electrical conductivity. Its minimal dimensional impact makes it useful for precision parts in aerospace, automotive, and electronics applications.
MIL-DTL-5541 distinguishes Type I coatings, which contain hexavalent chromium, from Type II coatings, which do not. RapidDirect uses Type II as its default Alodine finish.
- Corrosion resistance:
The chemical film helps protect aluminum parts from corrosion.
- Paint adhesion:
The coating improves adhesion of paints and primers.
- Electrical conductivity:
The thin coating maintains the electrical conductivity of the aluminum part.
- Minimal dimensional change:
The thin film has little effect on part dimensions.
- Cost-effective:
Alodine is a cost-effective coating process.
Alodine Specifications
| Property | Specification |
|---|---|
| Applicable Materials | Aluminum and its alloys |
| Color Options | Clear, yellow |
| Thickness | 0.25–1.0 µm (0.00001–0.00004 inches) |
| Applications | Aerospace, automotive, and electronics |
Alodine Finished Parts



Alodine FAQs
Find answers about Alodine finishes and project requirements.