Mist it is a chemical process that creates a layer of aluminum oxide so to speak , this explains it better
What is Anodizing?
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.