Anodizing is an electrochemical process that grows a durable oxide layer on aluminum, dramatically improving corrosion resistance, hardness and appearance. It is the default finish for most machined aluminum parts.
How Anodizing Works
The aluminum part is submerged in an acid bath and connected as the anode. An electric current grows a controlled oxide layer that bonds with the surface at the molecular level.
Type II vs Type III
Type II (sulfuric) anodizing is the standard decorative finish, offering a range of colors. Type III (hardcoat) produces a much thicker, harder layer for wear resistance in demanding applications.
Color Options
Natural (clear), black, gold, red, blue, green and custom colors are all achievable. Dyes are absorbed into the porous oxide layer before sealing, producing uniform, durable color.
Benefits for Machined Parts
Anodizing improves corrosion and scratch resistance, provides electrical insulation, and enhances aesthetics. It does not peel or flake because the layer is grown from the metal itself.
Design Tips
Mask threaded holes and tight-tolerance surfaces if they must not be coated. Be aware anodizing adds a small, predictable thickness that can affect press fits.
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