Seven pieces of corroded silver foil.
- Found/Acquired: Egypt
- Length: 13 centimetres (largest piece)
- Width: 5.5 centimetres (largest piece)
- Thickness: 0.03 centimetres
2 June 2004
Reason for treatment
Remove blue corrosion if possible, strengthen cracks and tears.
The copper-alloy foil pieces are in very fragile condition. They have a dark reddish/brown surfaces which might be the indication of chemical stripping. Blue corrosion deposits are present on the surface. Analysis was undertaken by the Conservation research and was identified as sodium copper acetate.(Acetate from the storage environment, sodium might be either from the burial or from the past conservation treatments.). There are also waxy, light greenish corrosion layer on the surface of the metal which is identified as the malachite.There are cracks and tears especially in the middle part and around the edges of the fragments. (DC)
A cleaning test was undertaken to remove the blue corrosion product. Swabbing with distilled water sucessfully removes a sample area of the corrosion layer.(DC)Lightly mechanically cleaned with air-abrasive using sodium bicarbonate powder.Cleaned manually using scalpel under magnification.Cleaned using distilled water applied on cotton wool swabs.Unsightly blue powdery corrosion deposits sucessfully removed by a combination of these methods. Repaired using HMG adhesive (cellulose nitrate).Tears individually backed using HMG adhesive (cellulose nitrate) reinforced using discrete strips of nylon gossamer tissue.Consolidated using 5% Paraloid B72, ethyl methacrylate copolymer, in acetone, applied using brush.Support mount made using *PLAZT* with a detachable cover sheet of Melinex (FS)
25 January 2004
Reason for analysis
Identification Of Corrosion Products And Base Metal From Metal Foil Aes 1912.0217.191
Blue and light green corrosion products on metal foil AES 1912.2-17.191 were analysed using Fourier transform infrared spectrometry (FTIR). The blue corrosion product was found to be sodium copper acetate carbonate and the light green was identified as malachite. The metal was analysed by X-ray fluorescence (XRF) and was found to be copper (Cu).
Analysis reference number
Ancient Egypt & Sudan
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Object reference number: YCA39493
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