Current Approaches, Solutions and Practices in Conservation of Cultural Heritage

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DOI :10.26650/B/AA9PS34.2024.006.015   IUP :10.26650/B/AA9PS34.2024.006.015    Full Text (PDF)

Scientific Methodology for the Study of Corrosion Mechanisms, Morphologies and Cracking in Archaeological Copper-base Objects

Omid Oudbashi, Russell Wanhill

Understanding the corrosion processes of archaeological metals, corrosion mechanisms and morphologies, including cracking, are essential for conservation scientists; and also important for conservators, curators and archaeologists. Knowledge of particular aspects of corrosion in ancient metals and alloys is required for deciding how best to preserve heritage artefacts. In addition, the corrosion products themselves are interesting. There may be only a thin noble patina or corrosion crust, combinations of thick corrosion layers with metallic remnants, or completely corroded and mineralized objects that yet retain their original shape. Also, corrosion layers may retain some historical and even technological aspects of metalworking of interest for conservation scientists, archaeometallurgists and archaeologists. In this Chapter, we discuss three aspects of the study and analysis of corrosion in archaeological copper alloys, especially tin bronzes:

  • The types of corrosion found on (and in) archaeological copper alloy artefacts recovered from aerobic soil burial environments. Examples are given of internal corrosion damage and the corrosion layers and morphologies, which can be complex. 
  •  The more usual and available analytical methods for the study and analysis of corrosion in these artefacts. Most of the information about the corrosion phenomena and damage has been obtained via invasive sampling, using a variety of techniques. This is sometimes not allowed, notably for high-status artefacts. Recourse must then be made to noninvasive methods, such as visual analyses and surface (or near-surface) chemical composition measurements of corrosion products; and also the refurbished alloy surfaces, assuming that corrosion patinas may be removed.
  • Cracking and fracture mechanisms in moderately to severely damaged (fragmented) artefacts. This is a specialist topic requiring fractographic expertise in addition to the more usual examination methods. Examples of fracture surface analyses, in combination with metallography, are included to illustrate the contributions of fracture surface studies.

Keywords: Archaeological Copper Alloys, Corrosion Mechanisms, Analytical Methods

References

  • Artioli, G. (2010). Scientific Methods and Cultural Heritage: An Introduction to the Application of Materials Science to Archaeometry and Conservation Science, Oxford University Press, Oxford. google scholar
  • Artioli, G., Angelini, I. (2011). Mineralogy and archaeometry: fatal attraction. European Journal of Mineralogy, 23(6), 849-855. google scholar
  • Berthelon, R. (2007). Archaeological metal artefacts and conservation issues: long-term corrosion studies. In Corrosion of Metallic Heritage Artefacts: Investigation, Conservation and Prediction for Long-Term Be-haviour, Dillmann, P., Beranger, G., Piccardo, P., Matthiesen, H., Eds.; European Federation of Corrosion Publication 48; Woodhead Publishing: Cambridge, UK, pp. 31-40. google scholar
  • Casaletto M.P., De Caro, T., Ingo, G. M, Riccucci, C. (2006). Production of reference “ancient” Cu-based alloys and their accelerated degradation methods. Appl. Phys. A, 83, 617-622. google scholar
  • Chase, W.T. (1994). Chinese bronzes: casting, finishing, patination and corrosion. In Ancient and Historic Me-tals: Conservation and Scientific Research (Part 2). Scott, D.A., Podany, J., Considine, B.B., Eds.; The Getty Conservation Institute, Los Angeles, CA, USA, pp. 85-118. google scholar
  • Constantinides, I., Adriaens, A., Adams, F. (2002). Surface characterization of artificial corrosion layers on copper alloy reference materials. Appl. Surf. Sci., 189 (1-2), pp. 90-101. google scholar
  • Di Fazio, M., Felici, A.C., Catalli, F., Medeghini, L., De Vito, C. (2022). Micro and Nanoscale Structures and Corrosion Patterns in Brass: The Case Study of Ancient Roman Orichalcum Coins. Minerals, 12, 827. https://doi.org/10.3390/min12070827 google scholar
  • Fell, V., Mould, Q., White, R. (2006). Guidelines on the X-radiography of Archeological Metalwork. Swindon: English Heritage. google scholar
  • Fernandes, R. (2009). Study on Roman and Merovingian copper alloyed artefacts-In soil corrosion processes and recycling practices. MSc Thesis, Vrije Universiteit Amsterdam. google scholar
  • France-Lanord, A. Ancient Metals, Structure and Characteristics: Technical Cards. Rome, ICCROM, 1980. google scholar
  • Franke, W.A., Mircea, M. (2005). Plutarch’s Report on the Blue Patina of Bronze Statues at Delphi: A Scientific Explanation. JAIC, 44, 103-116. google scholar
  • Hajjari, E., Oudbashi, O., Hemati Azandaryani, E. (2021). Technical studies on the mechanisms of corrosion and state of conservation of two hoards of Persian copper coins (folus) from the Safavid period in Iran, Journal of the Institute of Conservation, 44(2), 86-98. google scholar
  • Ingo, G.M., Angelini, E., Bultrini, G., Calliari, I., Dabala, M., De Caro, T. (2002). Study of long-term corrosion layers grown on high-tin leaded bronzes by means of the combined use of GDOES and SEM + EDS, Surf. Interf. Analy., 34, 337-342. google scholar
  • Ingo, G., Angelini, E., de Caro, T., Bultrini, G., Calliari, I. (2004). Combined use of GDOES, SEM + EDS, XRD and OM for the microchemical study of the corrosion products on archaeological bronzes. Appl. Phys., A 79, 199-203. google scholar
  • Ingo, G.M., Balbi, S., De Caro, T., Fragala, I., Angelini, E., Bultrini, G. (2006). Combined use of SEM-EDS, OM and XRD for the characterization of corrosion products grown on silver roman coins. Appl. Phys., A83, pp. 493-497. google scholar
  • Ingo, G.M., Riccucci, C., Guida, G., Albini, M., Giuliani C., Di Carlo, G. (2019). Rebuilding of the burial environ-ment from the chemical biography of archaeological copper-based artifacts. ACS Omega, 4, pp. 11103-11111. google scholar
  • Lehmann, E.H., Vontobel, P., Deschler-Erb, E., Soares, M. (2005). Non-invasive studies of objects from cultural heritage, Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 542, 1-3, pp. 68-75. google scholar
  • Liang, Z., Jiang, K., Zhang, T., Lin, S., Corrosion behavior of brass from the Western Zhou Dynasty in an arc-heological-corrosive medium. J. Alloys Comp. 865 (5), 2021,158579. google scholar
  • Luo, W., Jin, R., Qin, Y., Huang, F., Wang, C. (2010). Analysis of the Corrosion Products of the Ancient Bronzes Excavated from Qiaojiayuan Tombs. Applied Physics Research, 2, 156-169. google scholar
  • Mabille, I., Bertrand, A., Sutter, E.M.M., Fiaud, C. (2003). Mechanism of dissolution of a Cu-13Sn alloy in low aggressive conditions. Corros. Sci., 45 (5), pp. 855-866. google scholar
  • McNeil, M.B., Little, B.J., (1999). The Use of Mineralogical Data in Interpretation of Long-Term Microbiologi-cal Corrosion Processes: Sulfiding Reactions. JAIC, 38, 186-199. google scholar
  • McNeil, M.B., Little, B.J. (1992). Corrosion Mechanisms for Copper and Silver Objects in Near-Surface Envi-ronments. JAIC, 31, 355-366. google scholar
  • Meeks, N. (1993). Surface characterization of tinned bronze, high-tin bronze, tinned iron and arsenical bronze. In Metal Plating and Patination: Cultural, Technical and Historical Developments; La Niece, S., Craddock, P., Eds., Butterworth-Heinemann Ltd.: Oxford, UK, pp. 247-275. google scholar
  • Mödlinger, M., Sabatini, B. A. (2016). Re-evaluation of inverse segregation in prehistoric As-Cu objects. J. Archaeol. Sci., 74, pp. 60-74. google scholar
  • Mortazavi, M., Kavosh, H., Naghavi, S., Khanjari, R. (2022). Microstructural and analytical study of uncommon corrosion features on archaeological Cu-As alloys from Tappeh Graziani in Southeastern Iran. Microsc. Microanal, 28(2), pp. 302-316. google scholar
  • Oddy, W.A., Meeks, N.D. (1982). Unusual phenomena in the corrosion of ancient bronzes. in Science and Te-chnology in the Service of Conservation; Brommelle, N.S., Thomson, G., Eds.; International Institute for Conservation of Historic and Artistic Works; IIC Washington Congress, pp. 119-124. google scholar
  • Oudbashi, O. A. (2018). methodological approach to estimate soil corrosivity for archaeological copper alloy artefacts. Herit. Sci., 6 (2),(15 pages): DOI: 10.1186/s40494-018-0167-4 google scholar
  • Oudbashi, O. (2016). Corrosion risk assessment approach in archaeological bronze collections: From burial to long-term preservation environments. In Metal 2016: Proceedings of the Interim Meeting of the ICOM-CC Metals Working Group, September, 26-30, 2016, New Delhi, Menon, R., Chemello, C., Pandya, A., Eds., International Council of Museums - Committee for Conservation (ICOM-CC), pp: 188-194. google scholar
  • Oudbashi, O. (2015). Multianalytical study of corrosion layers in some archaeological copper alloy artefacts. Surf. Interface Anal., 47 (13), pp. 1133-1147. google scholar
  • Oudbashi, O., Bahadori, S., Aliyari, A. (2022). “Corrosion Analysis and Assessment of a Collection of Archae-ological Copper Alloy Objects from Sagzabad, Northern Iran,” Proceedings of the Interim Meeting of the ICOM-CC Metals Working Group, September, 5-9, 2022, Helsinki, 2022, 231-239. google scholar
  • Oudbashi, O., Wanhill, R.J.H. (2021). Long-term embrittlement of ancient copper and silver alloys. Heritage 2021, 4, pp. 2287-2319. DOI.ORG/10.3390/heritage4030130 google scholar
  • Oudbashi, O., Agha-Aligol, D., Mishmastnehi, M., Barnoos, V. (2019). The Elamite metalworkers: multianaly-tical study on copper objects and ingots from second millennium BC of southwestern Iran, Archaeological and Anthropological Sciences, 11, 2059-2072 google scholar
  • Oudbashi, O., Naseri, R., Heidarpour, B., Ahmadi, A. (2019). Study on the corrosion mechanisms and morpho-logy of archaeological bronze objects from a Bronze Age graveyard in Southwestern Iran. In Metal 2019, Proceedings of the Interim Meeting of the ICOM-CC Metals Working Group, Chemello, C., Brambilla, L., Joseph, E. (Eds.), International Council of Museums - Committee for Conservation (ICOM-CC) and Haute Ecole Arc Conservation-restauration (HE-Arc CR), 2019, pp. 150-157. google scholar
  • Oudbashi, O., Hasanpour, A., Jahanpoor, A., Rahjoo, Z. (2017). Microscopic and microanalytical study on Sasanian metal objects from Western Iran: A case study. STAR: Science & Technology of Archaeological Research, 3, pp. 194-205. google scholar
  • Oudbashi, O., Hasanpour, A., Davami, P. (2016). Investigation on corrosion stratigraphy and morphology in some Iron Age bronze alloys vessels by OM, XRD and SEM-EDS methods. Appl. Phys. A., 122:262. (11 pages): DOI: 10.1007/s00339-016-9793-4 google scholar
  • Oudbashi, O., Davami, P. (2014a). Investigation on Manufacturing Process in Some Elamite Copper Alloy Artefacts from Haft Tappeh, South-west Iran. Microscopy and Microanalysis, 20 (Suppl 3), pp. 2034-2035. google scholar
  • Oudbashi, O. Davami, P. (2014b). Metallography and microstructure interpretation of some archaeological tin bronze vessels from Iran. Mater. Character, 97, pp. 74-82. google scholar
  • Oudbashi, O., Emami, S.M., Ahmadi, H., Davami, P. (2013). Micro-stratigraphical investigation on corrosion layers in ancient Bronze artefacts by scanning electron microscopy energy dispersive spectrometry and optical microscopy. Herit. Sci., 1: 21. (10 pages). DOI: 10.1186/2050-7445-1-21 google scholar
  • Oudbashi, O., Emami, S.M. A. (2010). note on the corrosion morphology of some Middle Elamite copper alloy artefacts from Haft Tappeh, South-West Iran. Stud. Conserv., 55 (1), pp. 20-25. google scholar
  • Papadopoulou, O., Vassiliou, P., Grassini, S., Angelini, E., Gouda, V. (2016). Soil-induced corrosion of ancient Roman brass - A case study. Mater. Corros., 67 (2), pp. 160-169. google scholar
  • Papapelekanos, A. (2010). The critical R.H. for the appearance of “Bronze Disease” in chloride contaminated copper and copper alloy artefacts. E-Conserv. Mag., 13, pp. 43-52. google scholar
  • Park, J.S., Park, C.W., Lee, K.J. (2009). Implication of peritectic composition in historical high-tin bronze me-tallurgy. Mater. Character., 60 (11), pp. 1268-1275. google scholar
  • Piccardo, P., Mille B., Robbiola, L. (2007). Tin and copper oxides in corroded archaeological bronzes. In Corro-sion of Metallic Heritage Artefacts, Investigation, Conservation and Prediction for Long-Term Behaviour; Dillmann, P., Beranger, G., Piccardo, P., Matthiesen, H., Eds.; European Federation of Corrosion Publication 48; Woodhead Publishing: Cambridge, UK, pp. 239-262. google scholar
  • Pollard, A.M., Batt, C.M., Stern, B., Young, S.M.M. (2007). Analytical Chemistry in Archaeology, Cambridge university Press, Cambridge. google scholar
  • Quaranta, M., Sandu, I. (2010). On the Degradation Mechanism under the Influence of pedological Factors Through the Study of Archaeological Bronze Patina, “Alexandru Ioan Cuza” University of Iaşi Publishing House, Iaşi. google scholar
  • Robbiola, L., Portier, R., A. (2006). Global approach to the authentication of ancient bronzes based on the cha-racterization of the alloy-patina-environment system. J. Cult. Herit., 7 (1), pp. 1-12. google scholar
  • Robbiola, L., Blengino, J.-M., Fiaud, C. (1998). Morphology and mechanisms of formation of natural patinas on archaeological Cu-Sn alloys. Corros. Sci., 40 (12), pp. 2083-2111. google scholar
  • Robbiola, L., Fiaud, C., Harch, A. (1994). Characterisation of passive layers of bronze patinas (Cu-Sn Alloys) in relation with the tin content of the alloy. In European Federation Corrosion Publication, No 12, Marcus, P., Baroux, B., Keddam, M., Eds.; The Institute of Materials, London, UK, pp. 150-154. google scholar
  • Robbiola, L., Fiaud, C. (1993). Corrosion structures of long-term burial Cu-Sn alloys: Influence of the selective dissolution of copper. Ed. de la Revue deMetallurgie, 6, 157-162. google scholar
  • Rousaki, A., Moens, L., Vandenabeele, P. (2018). Archaeological investigations (archaeometry), Physical Scien-ces Reviews, 3, pp. 20170048. google scholar
  • Saraiva, A.S., Figueiredo, E., Âguas, H., Silva, R.J.C. (2020). Characterisation of archaeological high-tin bronze corrosion structures, Stud. Conserv. DOI: 10.1080/00393630.2020.1857523 google scholar
  • Scott, D.A. (2002). Copper and Bronze in Art: Corrosion, Colorants and Conservation; The Getty Conservation Institute, Los Angeles. google scholar
  • Scott, D.A. (2000). A review of copper chlorides and related salts in Bronze corrosion and as painting pigments. Stud Conserv., 45, 39-53. google scholar
  • Scott, D.A. (1990). Bronze disease, a review of some chemical problems and the role of relative humidity. J. Am. Inst. Conserv., 29, pp. 193-206. google scholar
  • Scott, D.A. (1985). Periodic corrosion phenomena in bronze antiquities. Stud. Conserv., 30 (2), pp. 49-57. google scholar
  • Scott, D. A., & Schwab, R. (2019). Metallography in Archaeology and Art, Cham, Switzerland: Springer Nature. google scholar
  • Selwyn, L.S. (2006). Corrosion of metal artifacts in buried environments. In ASM Handbook Volume 13C, Corrosion: Environments and Industries; ASM International, Materials Park, OH, USA, pp. 306-322. google scholar
  • Selwyn, L.S. (2004). Metals and Corrosion: A Handbook for the Conservation Professional. Canadian Conser-vation Institute, Ottawa. google scholar
  • Stuart, B.H. (2007). Analytical Techniques in Materials Conservation, Wiley. google scholar
  • Taube, M., Davenport, A.J, King, A.H., Chase, W. (1996). Selective dissolution in copper-tin alloys: Formation of corrosion-resistant patina on ancient Chinese bronze mirrors. MRS Proc., (432), pp. 283-288. google scholar
  • Thickett, D., Cheung, C.S., Liang, H., Twydle, J., Maev, R.G., Gavrilov, D. (2017). Using non-invasive non-dest-ructive techniques to monitor cultural heritage objects. Insight - Non-Destructive Testing and Condition Monitoring, 59(5), pp. 230-234. google scholar
  • Varella, E.A. (2013). Conservation Science for the Cultural Heritage: Applications of Instrumental Analysis, Springer. google scholar
  • Vink, B.W. (1986).Stability Relations of Malachite and Azurite. Mineralogical Magazine, 50, 41-47. google scholar
  • Wanhill, R.J.H., Oudbashi, O. (2023). Fractography of ancient metallic artifacts: archaeometallurgical fracture analysis and restoration and conservation aspects. In ASM Handbook Volume 12, Fractography, Second Edition; Schroeder, C.J., Parrington, R.J., Maciejewski, J.O., Lane, J., Eds; ASM International, Materials Park, Novelty, OH, USA. google scholar


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