1. Pitting Corrosion: Pitting corrosion is a localized dissolution that occurs at the point where the passivation film breaks. It is one of the most important corrosion modes for aluminum because it can penetrate deep, localize, and is difficult to detect early. Chloride contamination is a typical triggering factor.

2. Electrochemical Corrosion: Aluminum may preferentially corrode when electrically coupled to a more valuable metal in humid conditions. This is both a design and a chemical issue: dissimilar metal contact, trapped moisture, and poor isolation all increase the risk.

3. Crevice Corrosion: Crevice corrosion occurs in shielded, enclosed areas where the local chemical composition differs from the open surface. It is closely related to pitting corrosion because both are caused by passivation film breakdown and localized electrochemical imbalances.

4. Filament Corrosion: Filament corrosion manifests as random, unbranched white tunnels of corrosion products, usually under coatings or on unprotected metal. It typically causes more damage to appearance than strength, although thin sheets can be perforated.

5. Intergranular Corrosion: Some aluminum alloys are susceptible to intergranular attack when alloying or heat treatment produces unfavorable grain boundary precipitation. A typical example is high-magnesium forged alloys, where almost continuous Al₈Mg₅ precipitation at grain boundaries increases susceptibility to spalling or stress corrosion cracking.

In addition to the above types, aluminum alloy corrosion also manifests as the following phenomena:

Uniform corrosion: Overall surface thinning, commonly seen in acidic environments (e.g., annual corrosion rate exceeding 50 μm at pH < 4).

Crevice corrosion: Caused by oxygen concentration differences at fastener joints, such as in the riveted parts of aircraft skin.

Filamentous corrosion: Spreads in a spider web pattern under organic coatings, and is prone to occur when humidity is >65%.

Time：13/11/2026 16:41:06

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