Seven copper objects, representing little models of knives, spatulas and axes, found during the excavations of the Archeological Italian Mission of the Egyptian Museum of Torino, in Egypt at Gebelein, in 1910, in the ruins of a temple of the goodness Hathor, were analyzed by means of X-ray diffraction and of plasma-source mass spectrometry. During their recovery, the remotion of the corrosion products lead to the discovery, on five samples, of the inscription of the pharaoh Thutmosis III (1504-1450 b.C.), performed with two engraving techniques. The correlation between the trace elements in the base metal, the corrosion products and the presence of the inscription allows to emit some hypotheses on the hystory, mineral origin and technology of these ancient metallic artifacts. The choice of plasma-source mass spectrometry for the elemental analysis has been made taking into account the problem of primary importance which arises in the analysis of archaelogical samples: the need for non destructive techniques, or very sensitive destructive ones, in order to preserve the specimens. In this case the amount of sample utilized ranged from 1 to 6 mg. The multielement analysis reveals that all the samples are mainly constituted by copper, with minor amounts of As, Fe, Ni and Sn, and traces of other elements as Ag, Au, Cd, Co, Cr, Hg, Pb, Sb, Zn. The higher concentration of an alloying element, arsenic, is found for the sample 2, and is of the order of magnitude of 10000 ppm. Tin also reaches similar concentrations in samples 1 and 2, respectively 7819 and 8562 ppm. For the elements indicated as traces the concentrations range approximately from 500 ppm to 5 ppm. Sample 2 shows the greatest differences of composition with respect to the other six specimens, because of its greatest amounts of arsenic, most of all, iron, tin, and also cobalt and zinc. The other sample without inscription, 1, contains the same elements indicated above, in amounts lower than in sample 2 but higher with respect to the other five samples with the inscription. The major discrepancy between the composition of sample 6 and 7, of certain attribution, is the amount of tin and zinc, greater in sample 6, and nickel greater in sample 7. The most purified copper is the constituent of sample 4, which shows the lowest concentrations of the elements, the highest is tin, 1832 ppm. The greatest similarities can be observed between the compositions of sample 3, 5 and 7. The corrosion products of the seven samples removed during restoration, seem to be very similar in composition; while differences were observed between two groups of objects in the amounts of several trace elements. On the diffractograms high signals of copper basic chloride, CuCl2·3Cu(OH)2, together with the ones of Cu2O have been detected; this kind of patinas is not unusual for ancient copper objects. The comparison between the composition of the corrosion products and the bulk alloys shows interesting features, common to the seven alloys: a noteworthy enrichment of zinc, lead and manganese is observed, elements as Cr, Fe and Ni, decrease noticeably in several samples, while Cd, Au, Sb and Ag and disappear in the patina. Recent studies have shown that several elements, like arsenic, nickel, lead and silver, are reliable indicators of provenance for copper ores. The accurate determination of trace elements performed in this study on the bulk alloys will be used as a basis for indicating their source of origin, taking into account that the mines utilized in that period were located in Sinai and in the Eastern Desert.

Study of corrosion phenomena on ancient egyptian metallic artifacts / Angelini, EMMA PAOLA MARIA VIRGINIA; P., Bianco; E., Damicone; L., Vigna. - In: LA METALLURGIA ITALIANA. - ISSN 0026-0843. - STAMPA. - 84:2(1992), pp. 130-135.

Study of corrosion phenomena on ancient egyptian metallic artifacts

ANGELINI, EMMA PAOLA MARIA VIRGINIA;
1992

Abstract

Seven copper objects, representing little models of knives, spatulas and axes, found during the excavations of the Archeological Italian Mission of the Egyptian Museum of Torino, in Egypt at Gebelein, in 1910, in the ruins of a temple of the goodness Hathor, were analyzed by means of X-ray diffraction and of plasma-source mass spectrometry. During their recovery, the remotion of the corrosion products lead to the discovery, on five samples, of the inscription of the pharaoh Thutmosis III (1504-1450 b.C.), performed with two engraving techniques. The correlation between the trace elements in the base metal, the corrosion products and the presence of the inscription allows to emit some hypotheses on the hystory, mineral origin and technology of these ancient metallic artifacts. The choice of plasma-source mass spectrometry for the elemental analysis has been made taking into account the problem of primary importance which arises in the analysis of archaelogical samples: the need for non destructive techniques, or very sensitive destructive ones, in order to preserve the specimens. In this case the amount of sample utilized ranged from 1 to 6 mg. The multielement analysis reveals that all the samples are mainly constituted by copper, with minor amounts of As, Fe, Ni and Sn, and traces of other elements as Ag, Au, Cd, Co, Cr, Hg, Pb, Sb, Zn. The higher concentration of an alloying element, arsenic, is found for the sample 2, and is of the order of magnitude of 10000 ppm. Tin also reaches similar concentrations in samples 1 and 2, respectively 7819 and 8562 ppm. For the elements indicated as traces the concentrations range approximately from 500 ppm to 5 ppm. Sample 2 shows the greatest differences of composition with respect to the other six specimens, because of its greatest amounts of arsenic, most of all, iron, tin, and also cobalt and zinc. The other sample without inscription, 1, contains the same elements indicated above, in amounts lower than in sample 2 but higher with respect to the other five samples with the inscription. The major discrepancy between the composition of sample 6 and 7, of certain attribution, is the amount of tin and zinc, greater in sample 6, and nickel greater in sample 7. The most purified copper is the constituent of sample 4, which shows the lowest concentrations of the elements, the highest is tin, 1832 ppm. The greatest similarities can be observed between the compositions of sample 3, 5 and 7. The corrosion products of the seven samples removed during restoration, seem to be very similar in composition; while differences were observed between two groups of objects in the amounts of several trace elements. On the diffractograms high signals of copper basic chloride, CuCl2·3Cu(OH)2, together with the ones of Cu2O have been detected; this kind of patinas is not unusual for ancient copper objects. The comparison between the composition of the corrosion products and the bulk alloys shows interesting features, common to the seven alloys: a noteworthy enrichment of zinc, lead and manganese is observed, elements as Cr, Fe and Ni, decrease noticeably in several samples, while Cd, Au, Sb and Ag and disappear in the patina. Recent studies have shown that several elements, like arsenic, nickel, lead and silver, are reliable indicators of provenance for copper ores. The accurate determination of trace elements performed in this study on the bulk alloys will be used as a basis for indicating their source of origin, taking into account that the mines utilized in that period were located in Sinai and in the Eastern Desert.
1992
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11583/1653928
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