Type I, Chromic Acid Anodizing (CAA)

First commercial type of anodizing

Compatible with many aluminium alloys

Widely used in aerospace and defense

Minimise metal fatigue

Resist corrosion: 336 hours of 5% salt spray resistance as per ASTM B117



  • Thin anodic coating: .00002”-.0001” (20 to 100 micro inches)
  • Surface finish will be gray
  • Because it is thin, it will not be possible to be colored.


  • Good for tight tolerance parts: will not change dimensions
  • Good for Bonding
  • Non-Conductive
  • Good for welded parts and assemblies


  • Aerospace Components
  • as a final finish
  • as a base for paint
  • as a companion finish to hard anodizing (multi-processes)