Anodizing
The most common surface treatment of nonclad aluminum alloy surfaces. The aluminum alloy sheet or casting is the positive pole in an electrolytic bath in which chromic acid or other oxidizing agent produces an aluminum oxide film on the metal surface. Aluminum oxide is naturally protective, and anodizing merely increases the thickness and density of the natural oxide film.
Also defined in 2 more sources
The electrolytic process in which a hard, airtight, oxide film is deposited on aluminum alloy for corrosion protection.
A hard, airtight, unbroken oxide film electrolytically deposited on an aluminum alloy surface to protect it from corrosion.
Aviation Maintenance Technician Handbook — Powerplant, p. G-2
Taught in AF-K Procedures, AF-K Hands-on.