pitting

Pitting refers to the formation of small cavities or pits on a surface due to removal of material or mineral deposition by physical, chemical, or biological processes. The term is used across disciplines to denote localized pits rather than uniform etching or wear.

In corrosion science, pitting corrosion is a localized form of corrosion that leads to small, often deep pits. It is commonly observed in stainless steels and aluminum alloys. Initiation typically occurs at structural defects, inclusions, or sites where a protective passive film has broken down, with chloride ions and acidic conditions promoting pit formation. Once initiated, pits can concentrate aggressive species and propagate rapidly within a protective environment, making detection difficult until significant penetration occurs. Factors influencing pit initiation and growth include alloy composition, microstructure, temperature, environment, and applied stress. Prevention and mitigation strategies include use of resistant alloys, protective coatings, inhibitors, proper cleaning, and cathodic protection.

In dentistry, pits are shallow enamel depressions on the occlusal surfaces of teeth, often occurring together with fissures. These pits can harbor plaque and be susceptible to dental caries if not cleaned; prevention includes sealants, topical fluoride, and routine oral hygiene.

In other contexts, pitting may describe any localized cavity or indentation formed by erosion, abrasion, or mechanical impact.