The corrosion characteristics and electrochemical conservation treatment for an archaeological lead ossuary from Jordan

DOI: https://doi.org/10.37558/gec.v22i1.1093
Keywords: Lead, ossuary, corrosion, analysis, conservation, potentiostatic reduction

Abstract

This study investigates the composition and corrosion of a lead ossuary excavated from the archaeological cemetery located on the site of the Queen Alia International Airport, Jordan. It also presents its conservation treatment using the potentiostatic reduction method. X-ray fluorescence (XRF) and scanning electron microscopy/ energy dispersive X–ray spectroscopy (SEM/EDX) analyses showed that the ossuary was made from a relatively pure lead metal. Examination of the corrosion products using X–ray diffraction (XRD) and SEM/EDX analyses indicated the presence oxides, carbonates and chlorides of lead as the main corrosion products on the ossuary. The metallographic examination showed a cast α-Pb dendritic microstructure. A linear sweep voltammetry (LSV) scan for a small fragment from the ossuary in a sodium sulfate solution allowed identifying the working conditions to reduce the corrosion products to lead metal. Chronoamperometry (CA) techniques helped to monitor the reduction process and determine its completion. The potentiostatic methods showed an excellent effectiveness in determining treatment parameters and monitoring the reduction process of the corrosion products on the ossuary and to prevent over-treatment. The reduced ossuary was finally coated with Paraloid B72 to prevent corrosion reoccurrence in the poor environmental conditions of the storage area.

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Author Biography

Ahmad N. Abu Baker, Yarmouk University, Conservation and Management of Cultural Resources

Profesor Asociado del Departamento de Conservación y Manejo de Recursos Culturales de la Facultad de Arqueología y Antropología de la Universidad de Yarmouk, Irbid-Jordan Tiene títulos en química aplicada (BSc), conservación y gestión de recursos culturales (MA) y conservación de materiales culturales (PhD). Sus intereses de investigación incluyen: corrosión e inhibición de la corrosión de metales y aleaciones arqueológicos, técnicas electroquímicas en la conservación de metales, técnicas analíticas innovadoras aplicadas a la ciencia de la conservación y arqueometalurgia

References

ABDUL-SAMAD, F., THOMAS, J.H., WILLIAMS, P.A., BIDEAUX, R.A. AND SYMES, R.F. (1982). Mode of formation of some rare copper (II) and lead (II) minerals from aqueous solution, with particular reference to deposits at Tiger, Arizona. Transition Metal Chemistry, 7(1): 32-37, https://doi.org/10.1016/j.powtec.2018.07.082.

ABU-BAKER, A., AL SEKHANEH, W., SHIYAB, A., DELLITH, J., SCHEFFEL, A., ALEBRAHIM, M.A. AND POPP, J. (2014). Analytical investigation of five Roman Pb-based scale weights (Qasr Ar-Rabbah, Jordan): a case study. Mediterranean Archaeology and Archaeometry, 14(1):181-190.

ABU-BAKER, A.N. AND MACLEOD, I.D., (2021). An electrochemical simulation and treatment study for the carbonate and chloride based corrosion of heritage silver–copper alloys. Studies in Conservation, 66(4):190-210, https://doi.org/10.1080/00393630.2020.1796020.

BARRIO, J., CHAMÓN, J., PARDO, A.I. AND ARROYO, M. (2009). Electrochemical techniques applied to the conservation of archaeological metals from Spain: a historical review. Journal of Solid State Electrochemistry, 13(11):1767-1776, https://doi.org/10.1007/s10008-009-0876-4.

CALEY, E.R. (1955). Coatings and incrustations on lead objects from the Agora and the method used for their removal. Studies in Conservation, 2(2): 49-54, https://doi.org/10.1179/sic.1955.007.

CARRADICE, I.A. AND CAMPBELL, S.A., (1994). The conservation of lead communion tokens by potentiostatic reduction. Studies in conservation, 39(2):100-106, https://www.jstor.org/stable/1506559.

COSTA, V., (2003). Electrochemistry as a conservation tool: an overview. In Conservation science 2002: papers from the conference held in Edinburgh, Scotland 22-24 May 2002, 88-95.

COSTA, V. AND URBAN, F., (2005). Lead and its alloys: metallurgy, deterioration and conservation. Studies in Conservation, 50 (sup1): 48-62, https://doi.org/10.1179/sic.2005.50.Supplement-1.48.

CRADDOCK, P.T., (1995). Early metal mining and production. Edinburgh: Edinburgh University Press.

CRONYN, J.M., (1990). The Elements of Archaeological Conservation. Routledge.

DEGRIGNY, C. AND GALL, R.L., (1999). Conservation of ancient lead artifacts corroded in organic acid environments: electrolytic stabilization/consolidation. Studies in conservation, 44(3):157-169, https://doi.org/10.1179/sic.1999.44.3.157.

EDWARDS, R., GILLARD, R.D., WILLIAMS, P.A. AND POLLARD, A.M., (1992). Studies of secondary mineral formation in the PbO-H2O-HC1 system. Mineralogical Magazine, 56(382): 53-65, https://doi.org/10.1180/minmag.1992.056.382.07.

FONTAINE, C., GUILMINOT, E., JEANNERET, R. AND ROSSETTI, L., (2016). Determination of parameters for local electrolytic treatment of corroded lead and lead-tin alloys. Journal of Cultural Heritage, 20: 607-614, https://doi.org/10.1016/j.culher.2016.02.002.

GOWLAND, W., (1901). XXI.—The Early Metallurgy of Silver and Lead: Part I., Lead. Archaeologia, 57(2): 359-422, https://doi.org/10.1017/S0261340900014211.

IBRAHIM, M.M. AND GORDON, R.L., (1987). A cemetery at Queen Alia International Airport. Institute of Archaeology and Anthropology series.

MATTIAS, P., MAURA, G. AND RINALDI, G., (1984). The degradation of lead antiquities from Italy. Studies in Conservation, 29(2): 87-92, https://www.jstor.org/stable/1506079.

NOSEK, E.M., (1985). The investigation and conservation of a lead paten from the eleventh century. Studies in conservation, 30(1):19-22, https://doi.org/10.1179/sic.1985.30.1.19.

PALOMAR, T. AND CANO, E., (2018). Comparative assessment of mechanical, chemical and electrochemical procedures for conservation of historical lead. Journal of Cultural Heritage, 30: 34-44, https://doi.org/10.1016/j.culher.2017.10.010.

PALOMAR, T., RAMÍREZ, B., VÉLIX, J.M. AND CANO, E., (2018). Evaluation of cleaning procedures for the conservation of tarnished lead. In Conserving Cultural Heritage, 45-47.

PRABHAKAR, A., SALONITIS, K. AND JOLLY, M., (2019). Characterisation of lead sheet manufactured using traditional sand-casting technique. In Shape Casting, Springer, Cham. 283-292.

ROCCA, E., MIRAMBET, F. AND STEINMETZ, J., (2004). Study of ancient lead materials: A gallo-roman sarcophagus—contribution of the electrolytic treatment to its restoration. Journal of materials science, 39(8): 2767-2774, https://doi.org/10.1023/B:JMSC.0000021452.54819.fd.

SCHOTTE, B. AND ADRIAENS, A., (2006). Treatments of corroded lead artefacts: an overview. Studies in conservation, 51(4): 297-304.

SCHOTTE, B., ADRIAENS, A., DHOOGHE, F., DEPLA, D., DIERICK, M., DOWSETT, M., LEHMANN, E. AND VONTOBEL, P., (2006). Chemical and morphological changes of historical lead objects as a result of the use of electrolytic reduction as a stabilization treatment. Analytical chemistry, 78(24): 8319-8323, https://doi.org/10.1021/ac061381n.

SCOTT, D.A., (1992). Metallography and microstructure in ancient and historic metals. Getty publications.

SCOTT, D.A., 1996. A note on the metallographic preparation of ancient lead. Studies in conservation, 41(1): 60-62, https://doi.org/10.2307/1506553.

SELWYN, L., (2004). Metals and corrosion: a handbook for the conservation professional. Canadian Conservation Institute.

SELWYN, L., AND MCKINNON, W. R., (2017). Practical electrochemistry for conservators and conservation scientists: Part II: characterizing and treating corroded metals. Journal of the Canadian Association for Conservation, 42: 16-42.

ŠVADLENA, J., PROŠEK, T., STRACHOTOVÁ, K.C. AND KOUŘIL, M., (2020). Chemical removal of lead corrosion products. Materials, 13(24): 5672, https://doi.org/10.3390/ma13245672.

TURGOOSE, S., (1985). The corrosion of lead and tin: before and after excavation. In Lead and tin: studies in conservation and technology,15-26.

VANDER VOORT, G. F. (Ed.), (2004). Metallography and microstructures of lead and its alloys, Metallography and Microstructures, 9:789–800, https://doi.org/10.31399/asm.hb.v09.a0003773.

WATSON, J., (1985). Conservation of lead and lead alloys using EDTA solutions. Lead and Tin: Studies in Conservation and Technology, United Kingdom Institute for Conservation, 44-45.

Published
2022-12-20
How to Cite
Abu Baker, A. N. (2022). The corrosion characteristics and electrochemical conservation treatment for an archaeological lead ossuary from Jordan . Ge-Conservacion, 22(1), 154-161. https://doi.org/10.37558/gec.v22i1.1093
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Vol. 22 No. 1 (2022): Ge-conservación Nº22
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