After extrusion and heat treatment, aluminum profiles are supplied as mill-finished products. Aluminum naturally forms a thin oxide film when exposed to air, which helps prevent further oxidation. Mill-finished aluminum can be used directly, but to improve appearance, durability, corrosion resistance, and functional performance, various surface finishing processes are commonly applied.

Anodizing

Anodizing is an electrochemical process that thickens the natural oxide layer on the aluminum surface. A standard anodic film is typically 10–15 μm thick, offering improved corrosion resistance and a clean metallic appearance.

Hot anodizing: Uses elevated temperatures to achieve a A type of color anodizing that produces a uniform black finish.thicker oxide layer, up to 25 μm, for enhanced durability.

Black anodizing: A type of color anodizing that produces a uniform black finish.

Color anodizing: Adds dyes or electrolytic color to create bronze, champagne, gold, and other decorative finishes.

Hard anodizing: Produces an extremely thick and wear-resistant coating, typically 30–70 μm, suitable for mechanical components requiring high hardness and abrasion resistance.

Learn More about Anodizing

• Aluminum profile Anodizing
• Hard Anodizing
• Hard Anodizing

Electrophoretic Coating (E-coating)

Electrophoretic coating is applied after anodizing, using electrical attraction to deposit a uniform protective coating over the anodized surface. The process creates a smooth, glossy, and highly corrosion-resistant film with excellent color consistency. E-coating is available in a variety of colors—commonly clear, champagne, bronze, and black—and is often used for architectural aluminum profiles requiring a premium appearance.
The electrophoretic coating layer applied to aluminum profiles is primarily composed of water-based resins, pigments, additives, and crosslinking agents. This formulation results in a smooth, uniform, and visually appealing film with excellent adhesion properties. One of the key advantages of the electrophoretic process is its ability to produce an even coating, not only on flat surfaces but also over edges, weld seams, grooves, and other irregular or intricate areas of the profile. As a result, the entire aluminum profile receives comprehensive protection and a consistent decorative finish.

Bright and Aesthetic Finish: Electrophoretic coating delivers a highly transparent, smooth surface with enhanced metallic luster and a refined decorative effect.

Excellent Corrosion Resistance: It forms a dense protective layer, effectively resisting acids, alkalis, and salts, suitable for various environments.

High Hardness and Wear Resistance: The coated surface reaches a hardness of up to 4H, providing good durability against abrasion.

Electrical Insulation: The coating acts as an insulating layer, improving the profile’s safety in relevant applications.

Fingerprint Resistance: The electrophoretic coating provides an exceptionally smooth and non-porous surface, which significantly reduces the appearance of fingerprints and smudges.

Powder Coating

Powder coating allows aluminum profiles to be finished in virtually any color found in standard color charts, with options for glossy, matte, or textured appearances. The coating layer is typically 40–120 μm thick, providing excellent coverage and surface protection.

In production, powder coating can be applied using vertical or horizontal coating lines, depending on profile size and factory setup. Different powder formulations—such as standard polyester, super-durable polyester, and high-performance powders—can be selected based on the required weather resistance for architectural or industrial applications.

Powder coating has the following characteristics:

Corrosion Resistance: Forms a strong protective layer that safeguards against moisture and chemicals.

Enhanced Durability: Increases surface hardness, making the aluminum resistant to scratches and wear.

Variety of Colors and Finishes: Offers a wide selection of colors and textures, ensuring vibrant and consistent finishes that resist fading.
Powder coating for aluminum profiles provides a diverse array of color choices, leveraging the RAL color chart, an international standard for precise color matching. This standardized system ensures a wide and consistent selection of colors, catering to various design and aesthetic requirements. Popular RAL colors include RAL 9010 (Pure White), RAL 9005 (Jet Black), RAL 7016 (Anthracite Grey), and RAL 1015 (Light Ivory), among many others.

Ease of Maintenance: Creates smooth surfaces that are easy to clean and maintain.

Environmental Friendly: Produces minimal waste and avoids harmful chemicals, making it an eco-friendly process.

PVDF Coating

PVDF (polyvinylidene fluoride) is a fluoropolymer coating system applied to extruded aluminum profiles via multi-coat spray and high-temperature bake. Using architectural-grade PVDF resin (typically 70% fluoropolymer per Kynar 500/Hylar 5000 specifications), it forms a dense, UV-stable, and corrosion-resistant finish tailored to complex profile geometries.

PVDF coating offers the highest level of weather resistance among aluminum finishing methods. It provides exceptional UV stability, color retention, and corrosion resistance, making it ideal for curtain walls, coastal buildings, and high-end architectural projects. However, PVDF coating is also more expensive due to its multi-layer baking process and premium material cost.

Exceptional weatherability (20–30+ years): PVDF maintains color and gloss under strong UV, rain, salt spray, and thermal cycling, making it ideal for façades and exposed frames; proven field performance in coastal and desert climates shows low chalking and minimal gloss loss, supporting long warranties and extending repaint cycles.

Superior corrosion protection: The dense fluoropolymer barrier blocks moisture, chlorides, and industrial pollutants, and when paired with proper conversion coating and primer it resists underfilm corrosion at edges and joints; this is especially valuable for hollow and intricate extrusions where crevices can trap contaminants over time.

Outstanding color and fade resistance: Strong C–F bonds and UV-stable pigments deliver ultra-low chalking and minimal ΔE, even for dark, saturated, or metallic/mica colors, ensuring consistent appearance across orientations and elevations; this reduces replacements due to mismatch and preserves the original design intent.

Low dirt pickup and easy cleaning: The low-surface-energy finish sheds dust, soot, and grime, so routine rinsing with water and neutral detergent typically restores appearance; in polluted urban or coastal zones, reduced soiling and easier maintenance mean fewer cleaning cycles and lower access costs.

Flexibility and durability on complex profiles: PVDF retains flexibility after cure to accommodate expansion and contraction of long, thin-wall extrusions without cracking at corners or sharp radii, and it shows good mar/abrasion resistance during fabrication and installation when properly cured, reducing rework and touch-up on site.

Heat transfer printing is a decorative process used to apply patterns such as wood grain or stone effects onto aluminum profiles. By utilizing high temperatures, this method allows for the permanent transfer of intricate designs to enhance the visual appeal of aluminum products. It is commonly used in applications including doors and windows, furniture, and building facades.

The process begins with the anodization of the aluminum profile, creating a surface that can effectively absorb dyes. A transfer film, printed with the desired pattern, is then closely adhered to the aluminum surface using vacuum or pressure. The assembly is heated to 180–220°C for several minutes, causing the dyes in the film to sublime and penetrate the aluminum’s coating. Once cooled, the film is removed, leaving a durable and vivid pattern on the aluminum.

Realistic Wood Appearance: Mimics the look and feel of natural wood.

Weather Resistant: Mimics the look and feel of natural wood.

Lower cost Maintenance: Easy to clean and does not require painting or sealing.

Long-lasting Color: Maintains its color and finish even under sunlight and rain.

Comparation of Surface Treatment

Other Surface Treatments

Additional finishing methods can be applied to enhance appearance or functional performance. Polishing, brushing, and sandblasting are typically used as pre-treatment processes to create a smoother or more textured surface before anodizing, electrophoresis, or coating. Beyond these, aluminum profiles can also receive plated finishes, such as tin plating or other metallic coatings, to achieve specific decorative effects or specialized functional requirements.

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