A SCIENTIFIC STUDY OF THE PATINA, CORROSION MORPHOLOGY, AND CONSERVATION OF EGYPTIAN BRASS OBJECT
Document Type: Original article
Lecturer Conservation dept., Faculty of Fine Arts, Minia Univ., Minia, Egypt
This paper presents the way we used non-destructive methods-optical microscopy (OM), scanning electron microscopy (SEM) coupled with energy dispersive X-ray analysis (EDX), xray diffraction (XRD) and Fourier-transform Raman (FT-Raman) microscopy. The Raman spectra of copper were reported using an Nd-YAG laser operating at an excitation wavelength of 1064, 785and532 nm. These analyses were used to understand the corrosive morphological characteristics of the patina, to investigate the corrosion products, analyze the elementary composition of the copper object and to identify the corrosive factors with effects on the alteration processes. This object exhibited at the museum of the faculty of applied arts, Helwan university-Egypt. The results indicated that the object was made of brass alloy, with copper as the main element, beside zinc. Three layers of alteration products with various composition and morphology covered the substrate of the brass alloy. SEM-EDX, XRD analyses and Raman spectroscopy (RS) revealed the elements Cl, S, O, C, from primary and secondary chemical compounds and from soil micro-structure. This study provides useful information for the conservation of copper object.
Copper corrosion; minerals; Patina; Raman spectroscopy (RS); Brass treatment
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