Embrittlement of Ancient Silver

摘要

Ancient silver may become brittle and damaged owing to long-term corrosion and changes in the microstructure. Recognition and determination of corrosion-induced and microstructurally-induced embrittlement, and also their synergy, are important for restoration and conservation of ancient and historic silver. The types of embrittlement are described and illustrated, using examples of ancient and historic silver artefacts, including the famous Gundestrup Cauldron, a masterpiece of European Iron Age silverwork. In particular, the use of automated Electron BackScatter Diffraction (EBSD) enables improved analysis and assessment of corrosion-induced embrittlement. The knowledge obtained from detailed investigations is helpful not only in determining the best ways to restore and conserve embrittled silver objects, but also in defining the possible extent of the embrittlement problem. This is illustrated by a straightforward statistical analysis.