Aluminum anodizing is the electrochemical process that produces a stable film of aluminum oxide on the surface of the aluminum part at room temperature. The oxidation that occurs during the anodizing process creates an extremely hard and abrasion-resistant surface, increasing durability and corrosion resistance.

The aluminum oxide layer is formed and produces porous anodic coating that can be impregnated with various substances such as dyes. See our Anodizing Colors for more information on coating.

A typical anodize bath consists of sulfuric acid electrolyte, which when added to water, dissociates or separates. The aluminum metal is dissolved during the anodizing process and the reactions of aluminum ions combining with oxygen form aluminum oxide on the surface of the part. The anodic coating forms porous hexagonal cells, which creates a barrier layer on the surface of the aluminum.

Parameters that affect the sulfuric anodizing process include:

  • Time in tank
  • Current Density of process load
  • Voltage of direct current
  • Temperature of sulfuric bath
  • Acid concentration of sulfuric acid (free sulfuric acid content)
  • Dissolved aluminum amount (aluminum content)
  • Air agitation of anodize tank
  • Anode-to-Cathode ratio during anodizing process
  • Additives to the anodizing solution

Why Anodize: Anodizing vs. Powder Coating

  • Anodize will not peel, chip, rub or flake off
  • Provides better protective layer
  • Less susceptible to wear and tear, abuse and weather conditions
  • More cost-efficient
  • Sunlight-resistant from fading or stains (organic coatings tend to fail when exposed to ultra-violet light)
  • Lightweight, adding almost no additional weight to aluminum

Visit Floturn’s Anodizing Quality page for additional benefits of the anodizing process.

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