Anodizing
The anodizing of aluminum profiles is an electrochemical process that forms a layer of oxide on the surface of the aluminum, enhancing its protective properties. This oxide layer is significantly harder and more resistant to corrosion than natural aluminum, providing greater durability, wear resistance, and an attractive finish.
During this process, aluminum profiles are immersed in an electrolytic bath while an electric current is applied. This controlled oxidation forms a protective layer on the aluminum’s surface. The oxide layer can also be colored with dyes before sealing, allowing for a decorative and protective finish.
Stages
- Cleaning and Degreasing:
- Aluminum profiles are cleaned to remove dirty, grease, or residues that could interfere with the anodizing process.
- This step may include alkaline or acidic washes.
2. Etching:
- A surface treatment (typically with acidic solutions) is performed to remove a thin layer of aluminum and prepare the surface for anodizing.
- Anodizing:
- The profiles are immersed in a solution of sulfuric acid or chromic acid.
- An electric current is applied, causing the aluminum to act as the anode and form an oxide layer on its surface.
- The thickness of the oxide layer can vary depending on the requirements (typically between 5 and 25 microns).
- Coloring:
- In this phase, the porous oxide layer can be dyed using dyes or metals, such as nickel or cobalt, to provide a decorative finish.
- The profiles can remain in their natural color (silver) or be dyed in various shades.
- Sealing:
- The porous oxide layer is sealed by immersion in hot water or steam. This step blocks the pores, making the profiles more resistant to corrosion and wear.
- Sealing also ensures that the colors applied during the coloring process remain fixed and do not deteriorate.
- Inspection and Final Finishing:
- Anodized profiles are inspected to ensure they meet quality standards, including the thickness of the oxide layer and color uniformity.
- Final treatments may be applied according to customer specifications.
Equipment and Capabilities
The anodizing process is available at all production plants of Extrusiones Metálicas, both in Mexico and Spain, with the following locations nationwide:
Veracruz
Capacity 165,000 m²
- 3 Rectifiers | 15,000 Amp.
- 2 Color Rectifiers | 10,000 Amp.
Guanajuato
Capacity 175,000 m²
- 3 Rectifiers | 16,000 - 48,000 Amp.
- 1 Color Rectifier | 10,000 Amp.
- 1 Color Rectifier | 8,000 Amp.
Texcoco
Capacity 280,000 m²
- 4 Rectifiers | 12,000 Amp.
- 1 Color Rectifier | 10,000 Amp.
- 1 Color Rectifier | 8,000 Amp.
Importance of Anodizing:
- Protection: Increases the aluminum’s resistance to corrosion, wear, and mechanical damage.
- Aesthetics: Allows for the customization of profiles with high-quality decorative finishes and variety of colors.
- Durability: Enhances the lifespan of aluminum profiles in outdoor applications or harsh environments.
This process is commonly used in architectural, automotive, and electronic applications, where a combination of protection and aesthetics is required.