A BRONZE OSIRIS STATUETTE FROM THE EGYPTIAN MUSEUM IN CAIRO: MICROSTRUCTURAL CHARACTERIZATION AND CONSERVATION

Abstract

An Egyptian bronze statuette of the god Osiris has been discovered along with other ritual deities' statuettes and other metallic ritual equipment at Sais. It was temporarily inventoried with number 31/12/26/11C at the Egyptian Museum in Cairo. Its period, its specific burial place, and the certain excavation date were unknown. The statuette is an uncommon case; it was heavily corroded, covered with a thick crust of green corrosion products, has textile impression, missing its head, and has an unusual deep crack into its feet. It was examined, analyzed and conserved. Visual and stylistic examinations revealed that it is most probably dating to the Third Intermediate Period (1070-664 BC) or the Late Period (664-323 BC). Its style belongs to the Lower Egyptian style, and the direct solid lost-wax technique was used in the manufacturing process. Stereo-microscopic images revealed the Pseudomorph phenomenon on its surface.

X-ray diffraction (XRD) analysis revealed that the main compositions of the corrosion layer are oxychlorides, carbonates and sulphates covering copper and tin oxides. Structural examination and the elemental analysis by scanning electron microscopy (SEM) equipped with dispersive spectrometry (EDS) proved that the statuette was made of bronze material of Cu-Sn-Pb alloy. The high amounts of tin and lead affected on the mechanical properties of the bronze alloy and surely on its deterioration. Mechanical cleaning was applied so as to remove the superficial deposits / encrustations in a controlled and minimally obstructive way and then reaching a smooth layer which preserves the detail and shape. The surface of the Osiris statuette was protected with a corrosion inhibitor and protected against further corrosion attack with a protective coating.