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%.

A perforated tube is only the perforated metal skeleton, normally with open ends, without mesh or a seal.

A filter cylinder is a finished filter element, usually with a perforated tube as the inner support, outer woven mesh / sintered mesh, end caps, and a sealing gasket for direct installation.

While there is some overlap between perforated pipes and filter cylinders, they have different primary focuses.

Perforated pipes emphasize their tubular structure, fluid flow, support, protection, and perforation design. Filter cylinders, by contrast, focus on filtration precision, end caps, connection interfaces, sealing, and their specific function within a filtration system. A perforated pipe can serve as the core body of a filter cylinder, or it can function independently as a ventilation pipe, support pipe, protective sleeve, or silencer pipe.

No, aluminum does not rust. Rust is a corrosion product associated with iron and iron-rich alloys (such as steel). When exposed to oxygen, it forms a thin, tightly adhering film of aluminum oxide, which slows further corrosion rather than peeling off and exposing new metal. This oxide film is a key reason why aluminum is widely considered a naturally corrosion-resistant metal. It protects the aluminum inside from further corrosion, hence the common saying "aluminum doesn't rust."

The rust formed when iron rusts is loose and porous, and it will continue to corrode inwards; the oxide film of aluminum is dense, and its properties are different.

However, under conditions such as strong acid, strong alkali, seawater/chloride ion environment, mercury salt, etc., the oxide film of aluminum will be destroyed, and aluminum will also be corroded, resulting in phenomena such as whitening, powdering, and pitting, sometimes called "white rust" or aluminum corrosion.

Aluminum does not rust like iron, but it can oxidize and corrode under certain conditions.