November 29, 2009

Anodizing Definition

Anodizing define as electrolytic passivation, the process that affect on the metal to increase the thickness of the natural oxide layer on the surface of metal parts. The process to make this happen called as anodizing, this name merge from the source of process that use of anode electrode and electrical circuit.
Anodized metal will have a benefit to increase the corrosion resistance and wear resistance, and provides of better adhesion for paint primers and glues that bare metal. Other benefit of this treatments that the anodic films can be used as cosmetic effect, either with thick porous coating that can absorb dyes or with thin transparent coatings that add interference effect to reflected light. Anodizing also can be used to prevent of galling of threaded components and to make dielectric film for electrolytic capacitors. Anodic films are most commonly applied to protect aluminum alloys, although processes also exist for titanium, zinc, magnesium, niobium and tantalum. This process is not a useful treatment for iron or carbon steel because these metals exfoliate when oxidized,i.e. the iron oxide flakes off.

Thick coating are normally porous, this condition need for further treatment that is called as sealing process, this sealing process will make the oxide film change to more strong film. As an example of process application is on aluminum metal. Anodized aluminum surfaces are harder that aluminum but have low to moderate wear resistance that can be improved with increasing thickness or by applying suitable sealing substances.

No comments: