Aluminium Anodising

The process is called anodising because the aluminium part to be treated forms the anode electrode of an electrolytic cell.

Anodising increases resistance to corrosion and wear, and provides better adhesion for paint primers and glues than bare metal does.

Anodic films can also be used for several cosmetic effects, either with thick porous coatings that can absorb dyes or with thin transparent coatings that add interference effects to reflected light.

Anodising changes the microscopic texture of the surface and the crystal structure of the metal near the surface.

Thick coatings are normally porous, so a sealing process is often needed to achieve corrosion resistance.

Anodised aluminium surfaces, for example, are harder than aluminium but have low to moderate wear resistance that can be improved with increasing thickness or by applying suitable sealing substances.

Anodic films are generally much stronger and more adherent than most types of paint and metal plating, but also more brittle.

This makes them less likely to crack and peel from ageing and wear, but more susceptible to cracking from thermal stress.