Chemical Conversion Coating on Aluminum
A treatment in which the outer aluminum coat becomes a passive coat that protects the material from corrosion. This treatment also serves as a preparatory layer before painting as it does not change the original measurements of the material.
This treatment is also known by its generic name “Alodine” which is the commercial name of the substance used for these Types of treatments.
Chemical Conversion Coating Types
Conductive Conversion Treatment – A common process in the electronics industry where there is demand for electrically conductive aluminum. This Type of treatment creates a sheer or yellow finish.
Non Conductive Conversion Treatment – A yellow alodine treatment, used primarily for corrosion protection and as a basis for preparing aluminum for painting.
Standard MIL- DTL- 5541
Classification according to Type
| Type | Description of Treatment |
|---|---|
| Type I | Compositions containing hexavalent chromium- (chromatic passivation not ROHS compatible) |
| Type II | Non-hexavalent chromium passivation in accordance to ROHS |
Classification according to Class
| Class | Description of Treatment |
|---|---|
| Class 1A | Yellow passivation, for maximum protection against corrosion, painted or unpainted and serves as a preparatory layer before painting. |
| Class 3 | Conductive Passivation, used as protection against corrosion where low electrical resistance is required |
