Definition
A chemical surface treatment for aluminum and aluminum alloys that produces a thin, protective conversion coating on the metal. The coating resists corrosion and provides a good base for paint or primer. Unlike anodizing, alodizing is a simple chemical process that does not use electricity.
Plain English
A chemical dip or spray that puts a thin protective layer on aluminum parts to stop them from corroding and to help paint stick.
Context Anchor
Seen in aircraft maintenance when aluminum parts are cleaned, treated for corrosion protection, or prepared for primer and paint.
Derivation
The name comes from the trade name 'Alodine,' a brand of chromate conversion chemical used to treat aluminum. The verb 'alodizing' grew out of that brand name, much like 'xeroxing' came from Xerox. Knowing this explains why the word does not appear in older dictionaries -- it started as a product name.
Why Pilots Care
Aluminum aircraft skins and parts corrode easily, especially around exposed metal after repairs or scratches. A properly alodized surface is part of keeping the airframe airworthy and is often required before repainting a repair area.
Intuition Check
Alodizing is not the same as anodizing. Alodizing is a chemical process only; anodizing uses an electric current and produces a thicker, harder coating.
Example Sentence 1
After drilling out the damaged rivets and cleaning the bare aluminum, the technician alodized the area before applying primer.
Example Sentence 2
Alodizing the repaired skin section helps prevent corrosion in the humid coastal environment.