Natural anodizing is essential as aluminum tends to oxidize over time, even in environments that are not particularly aggressive. The process inhibits corrosion through the formation of a thin but very hard oxide layer, created through an electrolytic bath.
This layer improves the surface characteristics of the material, giving it greater resistance to corrosive agents, wear and abrasion, as well as superior hardness and dielectric insulation.
Functional and Decorative Aspect
In addition to its protective purpose, natural anodizing has decorative value: it allows coloring through pigments that penetrate the oxide layer. For this reason it is often referred to as decorative anodizing.
The main uses of the treatment are:
- Protecting parts from corrosion and increasing resistance to scratches and wear.
- Coloring aluminum through pigments that penetrate the pores of the coating.
Natural anodizing involves thicknesses between 5 µm and 25 µm (unlike hard anodizing which ranges between 30 µm and 50 µm). ISO 7599 standard identifies 5 typical thickness classes: 5, 10, 15, 20 and 25 µm.
Pre-treatments and Preparation
For a quality result, the surface must be perfectly clean through:
- Degreasing: to remove dirt, impurities and oils.
- Alkaline etching: cleaning and activation through sodium hydroxide.
- Acid etching: to dissolve oxides and other elements present in the alloys.
Post-treatments: Coloring and Sealing
- Coloring: The porous layer of decorative anodizing (low thickness and large pores) allows a wide range of colors. Conversely, hard anodizing takes on dark tones that limit color choice, making black the ideal solution to standardize different alloys.
- Sealing: Performed hot or cold, it serves to maintain and improve corrosion resistance over time.
Colors Available at Seritarghe
We perform natural and colored anodizing in the following standards:
- Orange, Light Blue, Blue, Yellow, Black, Red, Green, Lime Green.
Other colors are available upon request. The micron layer of the treatment is electronically controlled.