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Structural characterization of corrosion products on archaeological iron: an integrated analytical approach to establish corrosion forms
Author(s) -
Neff Delphine,
Reguer Solenn,
BellotGurlet Ludovic,
Dillmann Philippe,
Bertholon Régis
Publication year - 2004
Publication title -
journal of raman spectroscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.748
H-Index - 110
eISSN - 1097-4555
pISSN - 0377-0486
DOI - 10.1002/jrs.1130
Subject(s) - corrosion , characterization (materials science) , magnetite , electron microprobe , raman spectroscopy , materials science , goethite , microanalysis , scanning electron microscope , lepidocrocite , energy dispersive x ray spectroscopy , metallurgy , chemistry , nanotechnology , optics , composite material , physics , organic chemistry , adsorption
Abstract The description and identification of corrosion products formed on archaeological iron artefacts need various approaches at different observation scales. For this study, samples from five sites were prepared using two techniques. The first consists in cutting cross‐sections perpendicular to corrosion layers. This allows local observations and analysis of the corrosion layer stratigraphy at different levels. The second consists in performing manual grinding or abrading of the corrosion layers starting from the current surface of the excavated artefact to the metal core. It allows the description of the successive layers and is well adapted for the analysis on a larger scale. In addition to these two observation scales, the identification of the iron oxides formed needs the coupling of several complementary techniques. Elementary compositions were determined by scanning electron microscopy–energy‐dispersive x‐ray (SEM–EDX) analysis and electron probe microanalysis (EPMA). Structural identification was performed by x‐ray micro‐diffraction under synchrotron radiation (µXRD) and micro‐Raman spectroscopy. These analyses were performed on the same samples with both x‐ray diffraction and Raman spectroscopy in order to ensure a reliable characterization. In some cases there are some ambiguities or overlapping between signatures of different phases by µXRD (such as maghaemite–magnetite) or Raman spectroscopy (such as goethite–magnetite) which can be overcome by the association of the two methods. The final aim is to set up an analytical methodology that will be optimal for the study of ancient iron corrosion products. It is the first step in the study of long‐term mechanisms of iron in soil. Copyright © 2004 John Wiley & Sons, Ltd.