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different anodizing options for your aluminium profiles

Anodizing is a surface treatment for aluminum profiles. This finishing process uses electrolytic oxidation of the aluminum surface to create a protective oxide coat. The anodic coat is hydrated aluminum oxide and it is resistant to abrasion and corrosion. Most anodic coatings are transparent while some may be colored. The following types of anodizing are commonly used for aluminum profiles.

Type I Anodizing

Type I anodizing is done with chromic acid in the chemical bath. It is used for profiles that need a very thin coating and very high level of resistance to corrosion. This kind of anodizing also serves as a good primer for powder coating and liquid paint. Type I anodizing is used where machining of the profile after anodizing is not desired. It is also used for parts that have welded or rivet joints or recesses that are difficult to rinse easily. In addition to chromic acid, which is the most commonly used, there are non-chrome variants. Examples of acids used for Type I anodizing include: tartaric acid and boric-sulfuric anodizing.

Type II Anodizing

Type II anodizing makes use of sulfuric acid in the chemical bath. It is one of the most commonly used types of anodizing. Most architectural aluminum profiles and other aluminum products are anodized with Type II anodizing. Anodizing with sulfuric acid allows for color variation and almost any color in the rainbow can be added to the surface of the metal during the anodizing process. So it is commonly used for parts where decorative coloring is important. Type II anodizing may also be left as a clear and translucent coating. The thickness is usually about 0.1 to 1.0 mils. It is also the most affordable type of anodizing.

Type III  or Hard Coat Anodizing

Type III anodizing is also called hard coat anodizing or engineering hard coat. It is used when a very hard surface is required. It is commonly used in places where the aluminum profiles must have a strong scratch resistant surface. When the profiles will bear weight or they will be in an area where they are likely to be handled in a rough way, they may need the extra protection offered by this kind of anodizing.

In Type III anodizing, the acid and concentration of aluminum are usually the same as Type II anodizing. But instead of maintaining the operation at room temperature, the temperatures are slightly higher and could go up to 32 degrees Fahrenheit. The electric current is also applied for a longer time to achieve a thickness of up to 3.0 mils.

Bright Dip Anodizing

Bright dip anodizing is used to achieve a polished surface finish that looks like an electroplated surface. As the name implies, bright dip is a chemical electrolytic process that brightens the aluminum surface without leaving any deposits on its surface. The degree of brightness is usually determined by the kind of aluminum alloy and the original surface finish of the profile that is being processed.