Mapping of corrosion products of highly altered archeological iron using voltammetry of microparticles

Stability of Iron in Clays Under Different Leaching Conditions

“…This method was applied for quick and simple characterization of different HFO phases in clay minerals, alloys, and archeological objects (Cepriá et al, 2003;Doménech et al, 2013;Grygar et al, 2002). As discussed above, kaolinite (KH) and bentonite (BCR) were chosen for comparison of their Fe characteristics via a voltammetric method.…”

Electrochemical analysis of metallic heritage artefacts: voltammetry of microparticles (VMP)

“…An example of such applications is presented in Fig. 9.11, where a photographic image of an archaeological shield boss from the Iberian-Roman site (fourth century bc) of Torre la Sal, Spain, is superimposed with the voltammograms taken in different points of the piece using the 'one-touch' sampling [128]. Voltammograms in contact with 0.10 m HCl exhibit the characteristic features of different iron corrosion products, namely, magnetite, hematite and ochre/ goethite, thus providing a map of the distribution of the corrosion products on the shield boss.…”

Development of analytical methods for the characterization of tempera paintings at micro- and nano-scale and their deterioration and biodeterioration processes.

“…The results obtained from these electrochemical techniques can be rationalized on considering that the EG and EO reconstructed paint films are constituted by a more or less homogeneous distribution of pigment particles more or less entirely embedded by a layer of more hydrophobic binding medium and a hydrophilic layer where resulting secondary metal forms exist, as described for pictorial specimens containing lead pigments The electrochemical analysis of the EG@Fe and EO@Fe inoculated with fungi and bacteria was performed using 0.10 M HCl as the electrolyte because this was previously used in the study of the control specimens and reference materials. As previously indicated, this electrolyte has provided well-defined signals in the study of iron pigments and corrosion products (Doménech-Carbó et al, 2001, 2007a, 2013a.…”

“…The electrochemical analysis of earth-based specimens was performed using 0.10 M HCl as the electrolyte because this was previously found as providing well-defined signals for iron pigments and corrosion products (Doménech-Carbó et al, 2001, 2007a, 2013a. Finally, the shoulder IV can be associated to the presence of Mn(IV), which accompanies iron species in earths (Doménech-Carbó et al, 2001, 2007a, 2013a).…”

“…Finally, the shoulder IV can be associated to the presence of Mn(IV), which accompanies iron species in earths (Doménech-Carbó et al, 2001, 2007a, 2013a). vs. Ag/AgCl in the negative direction, the pigment displays two cathodic peaks at -0.25 (C 1 ) and -0.65 V (C 2 ) which are followed, in the subsequent anodic scan, by a series of stripping peaks at around +0.15-0.25 V (A 2 ) and 0.00-0.05 V (A 1 ).…”