Anodized aluminum sheet

What is anodized aluminum sheet?

Anodized aluminum sheet is an aluminum sheet placed in the corresponding electrolyte (such as sulfuric acid, chromic acid, oxalic acid, etc.) as an anode, and electrolysis is performed under specific conditions and the action of external current. A dense oxide film is formed on the surface of the aluminum sheet, and the colorless and porous nature of the anodized film is used to dye and protect the aluminum matrix.

A thin layer of aluminum oxide is formed on the oxidized surface of the aluminum sheet, with a thickness of 5 to 20 microns, and a hard anodized film can reach 60 to 200 microns.

Ultimately, it results in aluminum being harder than diamond. It is typically used in harsh environments or applications that require exposure to the elements. The process creates a hard coating that replaces the original substance. Plus, it won’t flake like regular rust, so aluminum oxide sheets can be used in many applications.

5052 aluminum sheet has good anodizing performance, and the color difference after anodizing is small.

What is the process of anodizing aluminum sheet?

Anodizing is accomplished by immersing the aluminum into an acid electrolyte bath and passing an electric current through the medium. A cathode is mounted to the inside of the anodizing tank; the aluminum acts as an anode, so that oxygen ions are released from the electrolyte to combine with the aluminum atoms at the surface of the part being anodized. Anodizing is, therefore, a matter of highly controlled oxidation—the enhancement of a naturally occurring phenomenon.

Anodizing process mainly includes:

Cleaning → pretreatment → electrolyte → current and time → anodizing → sealing → cleaning and drying

Cleaning: Before anodizing, metal parts need to be cleaned to remove surface grease and impurities. The cleaning process is usually carried out with alkaline or acidic solutions.

Pretreatment: Metal parts first undergo some pretreatment, such as deburring, grinding or polishing. This can improve the surface finish after anodizing to some extent.

Electrolyte: The metal part is placed in an electrolyte containing an oxidizing agent and other additives. The composition of the electrolyte depends on the metal used and the desired surface treatment.

Current and Time: Make the metal part anodic by adding a direct current to the electrolyte. The current and treatment time are adjusted according to the desired treatment effect.

Anodizing: In the electrolyte, an oxide film is formed on the surface of the metal parts. This process is called anodizing. During this process, the thickness and color of the oxide film depend on the electrolyte and current/time parameters used.

Sealing: By soaking in hot water or other sealants, the micropores of the oxide film are sealed, thereby enhancing its corrosion resistance and hardness.

Cleaning and drying: Processed parts need to be cleaned and dried to remove excess electrolyte and sealant.

Performance parameters of anodized aluminum sheets

Oxide film thickness	Chemical oxidation: the oxide film is thin, with a thickness of about 0.5 to 4 microns. Electrochemical oxidation: the oxide film thickness is about 5 to 20 microns. Hard anodizing: the oxide film thickness can reach 60 to 200 microns.
Oxide film hardness	Extremely hard: HV=1200-1500 Alloy aluminum: HV=400-800
Heat resistance	Compared with before oxidation, the high temperature resistance performance is greatly improved
Oxide film melting point	Up to 2320K
Conductivity	Excellent insulation, breakdown voltage 2000V
Corrosion resistance	Excellent, corrosion resistance for thousands of hours in ω=0.03NaCl salt spray
Adhesion	The combination with the body is very strong
Is it poisonous	Environmentally friendly and non-toxic, it can replace stainless steel and traditional spraying and electroplating processes
Heat resistance	It can withstand temperatures around 1500°C, while ordinary aluminum plates can only withstand 660°C.
Application	Abrasive materials and cutting tools, aluminum parts that require high heat resistance and insulation performance, such as pistons, cylinders, bearings, impellers of hydroelectric equipment, etc.

Why use anodised Aluminium?

Anodized aluminum sheet metal is a type of aluminum sheet that has undergone an anodization process. Anodization is an electrochemical process that thickens the natural oxide layer on the surface of aluminum, making it more durable, corrosion-resistant, and able to hold color and dyes. Here are some key features and uses of anodized aluminum sheet metal:

Enhanced Corrosion Resistance: Anodized aluminum has a thicker and more stable oxide layer on its surface, which provides excellent resistance to corrosion and oxidation. This makes it suitable for outdoor and marine applications.

Increased Durability: The anodization process hardens the surface of the aluminum, making it more scratch-resistant and durable. This makes it suitable for applications where the material may encounter wear and tear.

Color Options: Anodized aluminum can be dyed in various colors during the anodization process. This allows for a wide range of color choices for decorative and aesthetic purposes.

Electrical Insulation: Anodized aluminum has good electrical insulation properties, which can be advantageous in certain applications where electrical conductivity needs to be minimized.

Decorative and Architectural Use: Anodized aluminum is commonly used in architectural elements, such as building facades, curtain walls, and decorative trim, due to its durability and aesthetic appeal.

Consumer Products: It is also used in the production of consumer products like cookware, appliances, and electronic enclosures, where its durability and resistance to staining are important.

Lightweight: Aluminum itself is a lightweight material, and anodized aluminum maintains this property, making it suitable for applications where weight is a concern.

Easy Maintenance: Anodized aluminum is relatively easy to clean and maintain, requiring simple cleaning procedures to retain its appearance.

Non-Toxic and Environmentally Friendly: Anodizing is a non-toxic process, and anodized aluminum is considered environmentally friendly because it is durable and long-lasting, reducing the need for frequent replacements.

Features of anodizing aluminum sheet

• 1) Light weight, 1/3 weight of stainless steel
• 2) Anti-scratch, the surface hardness reaches Sapphire Grade
• 3) Non-poisonous and environmental protection
• 4) Anti-static, anti-fingerprint, easy to clean
• 5) The surface anodized layer will never fade or fall off

Uses of anodized aluminum sheets

1. Exposed metal frames on buildings
2. Premium anodized aluminum cookware
3. Outer space satellites
4. Frame materials for outdoor furniture and decorative items
5. Protective cases for modern computer systems
6. Protective cases for modern household appliances
7. Anodized aluminum sheet nameplate or roadsign

Disadvantages of anodized aluminum sheet

Price

The price is expensive. Due to the complex process and high technical requirements, the price of anodized aluminum sheet is much higher than that of mill finish aluminum sheet.

Color difference problem

The color difference problem of anodized aluminum sheets is not caused by production technology because the oxidation bath liquid is prepared from a variety of chemical elements. Every time a batch of aluminum materials is oxidized, the chemical composition in the bath liquid changes, so the bath liquid is oxidized and colored with variable values. Aluminum materials always have color differences.