Advertisement

Journal of Failure Analysis and Prevention

, Volume 5, Issue 1, pp 41–54 | Cite as

Embrittlement of ancient silver

  • R. J. H. Wanhill
Peer Reviewed Articles

Abstract

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.

Keywords

ancient silver cracks corrosion embrittlement grain boundaries 

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. 1.
    F.C. Thompson and A.K. Chatterjee: Stud. Conserv., 1954, 1, pp. 115–26.CrossRefGoogle Scholar
  2. 2.
    C.S. Smith: “The Interpretation of Microstructures of Metallic Artefacts,” Application of Science in Examination of Works of Art, W.J. Young, ed., Boston Museum of Fine Arts, Boston, 1965, pp. 20–52.Google Scholar
  3. 3.
    A.E. Werner: “Two Problems in the Conservation of Antiquities: Corroded Lead and Brittle Silver,” Application of Science in Examination of Works of Art, W.J. Young, ed., Boston Museum of Fine Arts, Boston, 1965, pp. 96–104.Google Scholar
  4. 4.
    R.M. Organ: “The Current Status of the Treatment of Corroded Metal Artefacts,” Corrosion and Metal Artefacts, NBS Special Publication 479, National Bureau of Standards/U.S. Department of Commerce, Washington, 1977, pp. 107–42.Google Scholar
  5. 5.
    M. Kallfass, J. Paul, and H. Jehn: Prakt. Metallogr.-Pr. M., 1985, 22, pp. 317–23.Google Scholar
  6. 6.
    I.G. Ravich: “Annealing of Brittle Archaeological Silver: Microstructural and Technological Study,” 10th Triennial Meeting of the International Council of Museums Committee for Conservation, Preprints of the Seminar: August 22/27, 1993, II, Washington, 1993, pp. 792–95.Google Scholar
  7. 7.
    R.J.H. Wanhill, J.P.H.M. Steijaert, R. Leenheer, and J.F.W. Koens: Archaeometry, 1998, 40, pp. 123–37.CrossRefGoogle Scholar
  8. 8.
    R.J.H. Wanhill: “Archaeological Silver Embrittlement: a Metallurgical Inquiry,” NLR-TP-2002-224, April 2002, National Aerospace Laboratory NLR, Amsterdam.Google Scholar
  9. 9.
    R.J.H. Wanhill: JOM-J. Min. Met. Mat. S., 2003, 55(10), pp. 16–19.Google Scholar
  10. 10.
    R.J.H. Wanhill: Archaeometry, 2003, 45, pp. 625–36.CrossRefGoogle Scholar
  11. 11.
    D.A. Scott: Archaeometry, 1996, 38, pp. 305–11.CrossRefGoogle Scholar
  12. 12.
    R.J.H. Wanhill, T. Hattenberg, and J.P. Northover: “Electron BackScatter Diffraction (EBSD) of Corrosion, Deformation and Precipitation in the Gundestrup Cauldron,” NLR-TP-2003-490, Oct 2003, National Aerospace Laboratory NLR, Amsterdam.Google Scholar
  13. 13.
    D.B. Williams and J.W. Edington: Acta Metall., 1976, 24, pp. 323–32.CrossRefGoogle Scholar
  14. 14.
    W. Gust: “Discontinuous Precipitation in Binary Metallic Systems,” Phase Transformations, The Institution of Metallurgists, London, 1979, pp. II-27-28.Google Scholar
  15. 15.
    R.D. Doherty: “Diffusive Phase Transformations in the Solid State,” Physical Metallurgy, R.W. Cahn and P. Haasen, ed., Elsevier Science B.V., Amsterdam, 1996, vol. II, pp. 1456–58.Google Scholar
  16. 16.
    J.P. Northover: personal communication, Department of Materials, Oxford University, 1999.Google Scholar
  17. 17.
    W. Scharfenberger, G. Schmitt, and H. Borchers: Z. Metallkd., 1972, 63, pp. 553–60.Google Scholar
  18. 18.
    W. Johnson and P.B. Mellor: Plasticity for Mechanical Engineers, D. van Nostrand Company Ltd., London, 1962, pp. 333–34.Google Scholar
  19. 19.
    W.A. Oddy and R. Holmes: “The Hockwold Treasure,” The Art of the Conservator, W.A. Oddy, ed., British Museum Press, London, 1992, pp. 137–50.Google Scholar
  20. 20.
    J. van Reekum and E. Moll: “Coating Silverware: from Daily Use to Museum Object,” Zeven IJzersterke Verhalen over Metalen (in Dutch), H.A. Ankersmit and J.A. Mosk, ed., Netherlands Institute for Cultural Heritage, Amsterdam, 2000, pp. 74–79.Google Scholar
  21. 21.
    K. Schmidt-Ott: “Plasma Reduction of Silver Surfaces” (in German), EXPOSURE 2001: Corrosion, Conservation & Study of Historic Metals in Situ, on Display & in Storage, to be published by Archetype, London, 2004.Google Scholar
  22. 22.
    R. Wood: Mater. World, 2000, 8(6), pp. 30–32.Google Scholar
  23. 23.
    F. Schweizer and P. Meyers: MASCA Journal, 1978, 1, pp. 9–10.Google Scholar
  24. 24.
    F. Schweizer and P. Meyers: “A New Approach to the Authenticity of Ancient Silver Objects: the Discontinuous Precipitation of Copper from a Silver-Copper Alloy,” Proceedings of the 18th International Symposium on Archaeometry and Archaeological Prospection, Rheinland-Verlag GmbH, Cologne, 1979, pp. 287–98.Google Scholar
  25. 25.
    R.J.H. Wanhill, J.P. Northover, and T. Hattenberg: “On the Significance of Discontinuous Precipitation of Copper in Ancient Silver,” NLR-TP-2003-628, Dec 2003, National Aerospace Laboratory NLR, Amsterdam.Google Scholar
  26. 26.
    B. Predel and H. Ruge: Z. Metallkd., 1968, 59, pp. 777–81.Google Scholar
  27. 27.
    W. Gust, B. Predel, and K. Diekstall: Z. Metallkd., 1978, 69, pp. 75–80.Google Scholar
  28. 28.
    A. Lucas: J. Egypt. Archaeol., 1928, 14, pp. 313–19.Google Scholar
  29. 29.
    N.H. Gale and Z.A. Stos-Gale: J. Egypt. Archaeol., 1981, 67, pp. 103–15.Google Scholar
  30. 30.
    G. Philip and T. Rehren: Oxford J. Archaeol., 1996, 15, pp. 129–50.CrossRefGoogle Scholar
  31. 31.
    W. Gowland: Archaeologia, 1918, 69, pp. 121–60.Google Scholar
  32. 32.
    N.H. Gale and Z.A. Stos-Gale: Sci. Am., 1981, 244(6), pp. 142–52.CrossRefGoogle Scholar
  33. 33.
    R.F. Tylecote: The Prebistory of Metallurgy in the British Isles, The Institute of Metals, London, 1986, pp. 54–61.Google Scholar
  34. 34.
    Ch.J. Raub: “The Metallurgy of Gold and Silver in Prehistoric Times,” Prehistoric Gold in Europe: Mines, Metallurgy and Manufacture, G. Morteani and J.P. Northover, ed., Kluwer Academic Publishers, Dordrecht, 1995, pp. 243–59.Google Scholar
  35. 35.
    H. McKerrell and R.B.K. Stevenson: “Some Analyses of Anglo-Saxon and Associated Oriental Silver Coinage,” Methods of Chemical and Metallurgical Investigation of Ancient Coinage, E.T. Hall and D.M. Metcalf, ed., Royal Numismatic Society, London, 1972, pp. 195–209.Google Scholar
  36. 36.
    R.J.H. Wanhill: “Ancient Silver Embrittlement: Significances of Copper, Lead and Cold-Deformation,” NLR-TP-2003-617, December 2003, National Aerospace Laboratory NLR, Amsterdam.Google Scholar
  37. 37.
    C. Lipson and N.J. Sheth: Statistical Design and Analysis of Engineering Experiments, McGraw-Hill Book Company, New York, 1973, p. 60.Google Scholar

Copyright information

© ASM International 2005

Authors and Affiliations

  • R. J. H. Wanhill
    • 1
  1. 1.National Aerospace Laboratory NLRAmsterdamThe Netherlands

Personalised recommendations