Corrosion of Metal Artifacts in Buried Environments

The corrosion processes of metals during burial are affected by environmental pollutants, other archaeological material, geography, microorganisms in the soil, vegetation, land use, soil chemistry, soil physical properties, and the presence or absence of water and air. This article discusses the key environmental variables that affect the corrosion of buried metal artifacts. These include water (including dissolved salts and gases), sulfate-reducing bacteria, pH (acidity), and potential (oxidizing or reducing capacity). The article contains tables that list some corrosion products identified on archaeological tin and pewter, lead, iron alloys, silver alloys, and copper alloys. It also discusses the corrosion problems after excavation and the techniques followed by archaeological department for conserving metal artifacts.