Tátrai Vilmos szerk.: A Szépművészeti Múzeum közleményei 95. (Budapest, 2001)
VOZIL, IRÉN: Technical analysis, restoration and evaluation of material testing of the bronze statuette of Imhotep
The purpose of the testing was to determine whether the various elements of the statue were different or identical. We also hoped to obtain some information for the relative chronology of the statue. The difference in hardness of the various parts of the bronze statue group was already evident during the restoration process. This difference was very conspicuous when samples were being collected for the testing. The material of the chair and the base is much more rigid and harder than that of the body. The elemental analytical tests confirmed the results of visual inspection and the observation during the sampling process. The difference in the mechanical properties of the two main parts is the consequence of the dissimilar alloys. The 10-13% lead content in samples Nos. 1-3 is regarded as medium or high limit according to the categorisation by Riederer. 16 The 6-23% tin content definitely belongs to a high tin content category. Based on this composition, the material of the sitting figure can be regarded as tin-lead bronze. The material testing of the chair and the base revealed that no lead can be detected in quantities exceeding the limit of detection. In their alloy, the content of tin varies in the range of 13-27 %. Thus the material can be regarded as a tin bronze containing a high quantity of tin. 17 The material of the base includes lead only as a contaminant, while the lead content of the body can be regarded as the result of an intentional addition. In the past decades several publications clarified changes in the composition of bronze products with regards to regions and chronology. 18 The most extensive list of compositions of dated products was published by A. Lucas. 19 Dated bronze compositions are shown in Fig. 4 of the study by Tóth et al. 20 A significant change can be observed in the composition of samples dated from Dynasties XX to XXV. 21 Investigations have shown that earlier alloys contain only a small quantity of lead, or no lead at all (the lead content of up to 5% could be regarded as the result of contamination), but the lead content of bronze products originating from later times is significantly higher. 16 Riederer, J., Archäologie und Chemie., Ausstellung des Rathgen-Forschungslahors, SMPK Berlin 1988, p.108. 17 Lucas, op.cit. (n. 12), p. 214, 217-8, 244, 251, 486-88. From a comparison of the bronze products used in various periods it can be seen that the tin-copper (tin bronze) alloys sporadically occurred already in Dynasty IV. Sometimes the tin content is extraordinarily high; Cu: Sn = 78% : 22%, however, the generally used concentrations are: Cu=90-95%, Sn=5-10%. IX Ogden, J., Metals, in: Nicholson, T. P.- Show, I., (ed.), Ancient Egyptian Materials and Technology, Cambridge (2000), 155. 19 See: Lucas, op.cit. p.485, No. 1. See also: Dunham, D., Boston Bull. XXIX.(1 931 ), p. 109; Pelleg, J., Baram, J., Oren, E. D., Analysis of Bronze Arrowheads of the Saite Period from the Nile Delta Region, Metallography 16 (1983), p 91-98. 20 Tóth et al., op. cit. 21 See in addition to that, alloys with extremely high lead content are mentioned in the following article in association with the Third Intermediate Period (Dynasty XXI-XXIV), but the examples mentioned are lead-bronze alloys with varying lead content (5-15-19 and 25 %): Taylor, J., Craddock, P. and Shearman, F., Egyptian hollow-cast bronze statues of the early first millennium BC, Apollo Magazine 12 (1998 ), pp. 9-14.
