Electro-chemical processing converts aluminum's metal surface into an architectural grade, durable, corrosion-resistant, anodic oxide finish. Aluminum is best suited to anodizing, but other nonferrous metals, such as titanium and magnesium, also can be anodized.
The anodic oxide structure starts from the aluminum substrate and is made up entirely of aluminum oxide. This aluminum oxide isn't brushed onto the surface like paint, but it is fully integrated with the underlying aluminum substrate. This integration makes it so it cannot chip or peel. It has a highly ordered, porous structure that allows for secondary processes such as coloring and sealing.
The process begins by immersing the aluminum into an acid electrolyte bath and passing an electric current through the bath. A cathode is mounted to the inside of the tank; the aluminum acts as an anode, and oxygen ions are released from the electrolyte to combine with the aluminum atoms at the surface of the part being anodized. In other words, anodizing is a matter of highly controlled oxidation— a naturally occurring phenomenon.
Uses for Anodized Aluminum:
- Protects satellites from the harsh environment of space.
- Used in one of the world's tallest buildings --- the Sears Tower in Chicago, Illinois.
- Provides attractive, minimum-maintenance, highly durable exteriors, roofs, curtain walls, ceilings, floors, escalators, lobbies and staircases in skyscrapers and commercial buildings throughout the world.
- Revolutionized the construction of computer hardware, exhibit displays for trade shows, scientific instruments, and a constantly expanding array of home appliances, consumer products, and building materials.
- Considered environmentally safe, producing few, if any, harmful effects on land, air, or water.