Anodized aluminum is aluminum that has been treated to develop an exceptionally durable finish. The process of anodizing is an electrolytic passivation process used to increase the thickness of the natural oxide layer on the surface of metal parts. Anodizing aluminum increases its corrosion resistance and allows for dyeing, improved lubrication, or improved adhesion. The anodic layer is insulative and does not increase the strength of the aluminum object. Anodized aluminum is used in a wide range of products, including MP3 players, smartphones, multi-tools, flashlights, cookware, cameras, sporting goods, firearms, window frames, roofs, and electrolytic capacitors.
The anodizing process involves immersing the aluminum directly into an acid electrolyte bath, typically sulfuric acid or chromic acid, which slowly dissolves the aluminum oxide. The acid action is balanced with the oxidation rate to form a coating with nanopores, 10–150 nm in diameter. The aluminum oxide is grown from the underlying aluminum substrate and has a highly ordered structure that is well suited for coloring and sealing. Unlike paint or plating, the finished anodized surface will not chip or peel.
Anodized aluminum is lightweight, weighing approximately 60 percent less than stainless steel, copper, or brass. This makes it much more cost-effective to ship and can solve a myriad of design issues. Anodized aluminum can be used in any application that already makes use of another metal material, and it is eco-friendly.
In summary, anodized aluminum is a type of aluminum that has undergone an electrochemical process to develop a durable finish that increases its corrosion resistance and allows for dyeing, improved lubrication, or improved adhesion. It is lightweight, versatile, and used in a wide range of products.
