What type of corrosion involves localized areas of corrosion that can penetrate the material?

Pitting corrosion refers to a type of corrosion characterized by the formation of small, localized pits or cavities on the surface of a material, typically metal. This type of corrosion is particularly dangerous because these pits can penetrate deep into the material, leading to significant structural weakening even when the overall surface might appear intact.

Pitting typically occurs in environments that promote localized attacks, such as in the presence of chlorides, and often happens in stainless steel and aluminum alloys. The nature of pitting makes it difficult to detect until considerable damage has occurred, as the affected areas are small and may be concealed by the surrounding material.

In contrast, other forms of corrosion, like surface corrosion or uniform corrosion, generally affect a broader area of the material and lead to more uniform wear rather than specific localized damage. Fret corrosion involves small mechanical movements between two parts that can lead to material degradation at the interface, but it does not typically describe the localized pitting characteristic. Therefore, pitting corrosion is the correct answer as it distinctly involves deep penetration of the material in localized areas.