Anodizing forms a dense oxide film on the surface of aluminum sheet, offering both wear resistance, corrosion resistance, and coloring properties. It is widely used in various fields. Its suitability is closely related to the alloy composition and purity of the aluminum sheet. This article will explain the suitable series and selection methods.

I. Core Requirements for Anodizing Aluminum Sheet

Purity Requirements: The higher the purity, the more uniform and transparent the oxide film. Excessive impurities (iron, silicon) can easily cause spots and color variations.

Alloying Element Compatibility: Magnesium and manganese can enhance the performance of the oxide film, while excessive copper and zinc content can affect stability.

Processability and Compatibility: Excellent stamping and bending properties are required to avoid deformation after oxidation.

II. Mainstream Aluminum Sheet Series Suitable for Anodizing

Aluminum sheets suitable for anodizing are primarily 1 Series (pure aluminum), 3 Series (aluminum-manganese alloy), and 5 Series (aluminum-magnesium alloy). Some 6 Series (aluminum-magnesium-silicon alloy) grades can be adapted through process adjustments. (I) Series 1 Aluminum Sheet: The "Basic Choice" for Anodizing

With an aluminum content of ≥99.00% (e.g., 1050, 1060, and 1100), advantages include:

The oxide film is uniform, dense, smooth, and transparent, suitable for natural or light-colored applications;

The simple composition and stable oxidation process make it suitable for mass production;

The low cost and high cost-performance ratio make it suitable for light-loaded exterior parts such as decorative panels and signs.

Limitations: Low mechanical strength prevents it from being used for load-bearing components.

(II) Series 3 Aluminum Sheet: The "Practical Choice" that balances performance and oxidation performance

With manganese as the main alloying element (e.g., 3003 and 3A21), containing 1.0%-1.5%, advantages include:

Strength is 30%-50% higher than Series 1, while the oxide film remains uniform, making it suitable for medium-to-low-load applications;

Corrosion resistance is superior to Series 1, making it suitable for humid environments such as kitchen equipment and indoor ceilings;

Good plasticity allows for processing complex shapes. Limitations: Dark colors can easily become unevenly dyed, and long-term outdoor use requires sealing to prevent discoloration.

(III) 5 Series Aluminum Sheet: The "Performance Choice" for High-Strength Applications

Using magnesium as the primary alloying element (such as 5052, 5083, and 5754), with a magnesium content of 2.0%-5.0%, these sheet types offer the following advantages:

High strength (5052 has a tensile strength of 230 MPa) and strong oxide film adhesion, making them suitable for applications where structural and exterior components are integrated (such as automotive interiors and outdoor display racks);

Excellent weather resistance, making them suitable for harsh environments such as outdoor curtain walls and traffic signs;

Multi-color dyeing is possible with optimized processing.

Limitations: High cost; high-magnesium grades (such as 5083) require stringent oxidation processing. (IV) 6 Series Aluminum Sheet: A "Supplementary Option" for Specific Applications

With magnesium and silicon as the primary alloying elements, suitability varies by model:

6063 aluminum sheet: Low magnesium and silicon content (magnesium 0.45%-0.9%, silicon 0.2%-0.6%), uniform oxide film with high hardness (HV300 and above), suitable for door and window profiles, and decorative railings;

6061 aluminum sheet: High magnesium, silicon, and copper content, prone to color shift during oxidation, suitable only for applications requiring high strength but low appearance (such as mechanical components).

Overall suitability is far inferior to 1, 3, and 5 Series aluminum sheets, making it a less preferred option.

III. Four Key Dimensions for Anodizing Aluminum Sheet Selection

Appearance requirements: For high transparency and light/natural colors, choose 1 Series; for low transparency, choose 3 or 5 Series aluminum sheets; for darker dyeing, prioritize 5 Series aluminum sheets.​

Strength Requirements: Choose Series 1 for light-load exterior parts; Series 3 for medium-to-low-strength structural parts; and Series 5 (5052, 5754) or 6063 for high-strength structural parts.

Use Environment: Choose Series 1, 3, or 5 for dry indoor environments; Series 3 or 5 for humid environments; and Series 5 or 6063 (with sealing required) for outdoor environments.

Cost Budget: Choose Series 1 for low budgets; Series 3 for medium budgets; Series 5 for high budgets and high-strength requirements; and 6063 for door and window profiles.

IV. Summary

Due to differences in composition, different series of aluminum sheet have distinct tiers in oxidation performance, performance, and cost: Series 1 prioritizes appearance, Series 3 balances performance and cost, Series 5 offers high-strength performance, and Series 6 only uses 6061 as a supplement. When selecting a product, avoid prioritizing strength over oxidation or cost over performance. A comprehensive decision should be made based on appearance, strength, environmental factors, and budget. Oxidation can be further enhanced by optimizing process parameters.