Anodizing of aluminium
Posted by P&A International
on Tuesday, 04 November 2014
in General Talk
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Anodising is a process for producing decorative and protective films on articles made of aluminium and its alloys. The article is made the anode of an electrolytic cell with aqueous sulphuric acid as electrolyte where the following overall oxidation reaction occurs.
2Al ÂÂ +3H2O→Al2O3 +6H+ +6e-
A dense even layer of oxide about 0.08 µm thick is formed rapidly, followed much more slowly with a more porous layer up to 25µm thick.
Before anodising the surface of the article must be thoroughly cleaned, normally using a detergent based process, and etched with a solution of sodium hydroxide.
After anodising the surface may...
Tags: ANODISING OF ALUMINIUM