Different Types of Anodizing Aluminum Process

Different Types of Anodizing Aluminum Process

    To know how to anodize aluminum, there is a need to know the types of aluminum used in the anodizing process. There are three commonly used types of anodizing process and each type of process results in a different set of functional and aesthetic properties.

How to anodize aluminum ?

Type I – Chromic Acid Anodize

Type I anodizing process uses chromic acid to create a thin coating on the surface of metal parts 

(up to 0.0001 inches).

Though Type I is the thinnest anodizing coating, it still results in parts with increased corrosion resistance. However, it also results in the least color absorption when dyed.

Type II – Sulfuric Acid Anodize

Type II anodizing process uses sulfuric acid instead of chromic acid. This results in a slightly thicker surface layer on the aluminum part.

Type II Sulfuric acid anodize has a thickness of 0.0002 to 0.001 inches and is better suited for dyeing parts.

Type III – Hardcoat Anodize

    This is often called “hard anodizing”, which also uses a sulfuric acid approach. However, it results in a thicker (> 0.001 inches) anodized layer when compared to Type II.

Hardcoat anodized parts have the best abrasion resistance and color dyeing potential. However, it may not be ideal for parts with extremely tight tolerances.