Anodic oxidation is a surface finishing treatment which consists in the formation of a thin layer of alluminum oxide on the surface of the material.
The oxide layer, obtained through an irreversible electrochemical process, allows to improve the mechanical surface characteristics of the material and avoid its corrosion.
The oxide layer that is formed has a gray color, the chromatic effects are obtained with the addition pigments.
Since the layer of oxide is porous, these pigments can easily adhere to aluminum, assuring very effective esthetic results, impossible to achieve with other treatments.
The number of shade variations increases with the combination of pre-treatments such as polishing or chemical satin finishing which give bright or matt effects to the piece. Moreover, the anodizing treatment increase corrosion resistance, surface hardness and improve lubrication properties.
Depending on the thickness of the treated layer, there are two types of anodization:
Thin anodic oxidation: it provides an oxide layer with a thickness from 5 μm to 25 μm and is usually a surface protection and aesthetic finishing treatment.
Thick anodic oxidation: provides a thicker layer of oxide, between 13 and 150 μ Hard anodizing is able to give better mechanical properties to the material, such as wear resistance, corrosion resistance and the ability to retain PTFE lubricants and other polymers.
The thickness of the oxide layer depends on various factors such as treatment time, intensity of the current that, when properly balanced,
allow different customized results.
Parameters such as roughness through roughness testers, thickness by magnetic micrometer, hardness with micro durometer and quality of fixing with drop test can be entered as ad hoc test certificates based on the specific needs of the treated parts.