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This paper presents the results of in situ non-destructive X-ray fluorescence determination of the chemical analysis of a collection of ten bronze statues that are on display at the Egyptian museum of Cairo. The statues are from the late period of the ancient Egyptian history. In addition, destructive technique X-ray diffraction analysis was applied on 11 damaged archaeological objects to determine the corrosion products and the alloy compositions. Specimens of the latter objects were subjected to metallographic examinations to determine the microstructure of the alloy. Surprisingly, the results indicated that all ten statues and 10 of the 11 damaged objects were made of leadbronze alloy; the percentage of the lead varied from 3.43 to 18.04, the tin varied from 2.53 to 10.67. The chemical composition of the patina on eight damaged objects is essentially composed of (Cu 2 O) cuprite for all objects in addition to other compounds such as (SnO 2 ) cassiterite in two objects, (PbCO 3 ) cerussite in three other objects and (Cu 2 (OH) 3 Cl) atacamite or (Cu(OH) 3 Cl) paratacamite in two other objects. The formation of chlorides and carbonate resulted from the interaction between surrounding environment and the alloy. The results of the metallographic examinations indicated a nonhomogenous structure and the increase of the lead content increases the globular lead particles. In spite of this condition, the galvanic corrosion tendency when the alloy is exposed to moist air or soil is not possible as lead compounds are electrically insulating. Another advantage for using leaded bronze in making statues is being heavy and thus leads to stability. a b c d Figure 4. Photomicrographs (a, b) and ED spectra (c, d) of specimen 11.

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Corrosion is a natural and inevitable problem that is still a challenge in materials design, with regard to achieving greater operational efficiency. In this study, the electrochemical and stress corrosion cracking (SCC) behavior of Cu10Ni alloy in a 3.5% NaCl solution in the presence of different concentrations of sulfide ions were studied. The presence of sulfide ions has been shown to increase the susceptibility of the material to SCC at different strain rates. The addition of glycine (gly) to the test electrolyte increased the time to failure by changing the mode of failure from brittle transgranular cracking to ductile failure. Therefore, gly can be considered as a potential environmentally friendly corrosion inhibitor. The electrochemical measurements showed that gly acts as a mixed corrosion inhibitor. The synergistic effect of potassium iodide (KI) and gly is also investigated. Electrochemical frequency modulation (EFM) and potentiodynamic polarization data are in good agreement with the SCC results.

The stress corrosion cracking (SCC) behavior of α-Al bronze alloy (Cu 7 Al) was investigated in 3.5% NaCl solution in the absence and in the presence of different concentrations of Na 2 S under open circuit potentials using the constant slow strain rate technique. Also, the addition of different concentrations of cysteine (cys), and alanine (ala) to the test solution, as corrosion inhibitors, was studied. Increasing the sulfide ions concentration in polluted salt water resulted in a reduction in the maximum stress (σ max) and an increase in the susceptibility of α-Al bronze towards SCC. The addition of ala and cys to the test electrolyte increased the time to failure by changing the mode of failure from brittle transgranular cracking to ductile failure. Electrochemical tests were performed to assist the interpretation of the SCC data. Electrochemical impedance spectroscopy (EIS) was used to investigate the mechanism of corrosion inhibition. The results support film rupture and anodic dissolution at slip steps as the operating mechanism of the SCC process. Therefore, cys and ala can be considered as potential environmentally-friendly corrosion inhibitors for the SCC of α-Al bronze in 3.5% NaCl solution containing sulfide ions.