The anodizing process

The most common way to anodize (anodise) an aluminum part.

  • Alkaline cleaner/degreaser – weak alkaline solution – removal of grease, oil and other contaminations.
  • Alkaline etch – strong alkaline solution – removal of aluminium from micron up to one hundredth part of the surface, depending of the solution and process time.
  • Desmutting/deoxidizing – acidic solution – removal of the heavy smut on the surface from the previous process baths.
  • Anodizing (Anodising) – weak acidic solution – the porous oxide layer is formed here by applying Voltage/Current.
  • Coloring – impregnation of the layer with the desired colour (this step is eliminated if the part is clear anodized.
  • Sealing – boiling water – this step closes the porous oxide layer, so the corrosion resistance is increased and color entrapped.

Between the process steps rinsing thorughly is one of the most important things to do, an it is often due to improper rinsing that a poor surface finish occurs.