Search results for "Voltammetry of immobilized particles"
showing 5 items of 5 documents
Multiple-scan voltammetry and OCP: Archaeometric tools for dating archaeological bronzes
2021
[EN] The application of a multiple-scan strategy to nanosamples taken from 18 cross-sections of Bronze Age arms and armour, as well as two Roman coins using two solid-state electrochemical techniques, the voltammetry of immobilized microparticles (VIMP) and open circuit potential measurements (OCP) is described. The voltammetric responses in contact with aqueous acetate buffer can be attributed to the reduction of cuprite with variable degree of compaction and crystallinity revealing significant differences in the gradient of such properties with depth. Such differences are also revealed by "dry" OCP measurements connecting points in the cross section near and separated from the corrosion l…
Characterizing archaeological bronze corrosion products intersecting electrochemical impedance measurements with voltammetry of immobilized particles
2017
Application of electrochemical impedance measurements to microparticulate deposits of copper corrosion products attached to graphite electrodes in contact with 0.10 M aqueous HClO4 electrolyte is described. The impedance measurements were sensitive to the applied potential and the amount of solid sample and were modeled taking into account the contribution of the uncovered base electrode. Several pairs of circuit elements provide monotonic variations which are able to characterize different corrosion compounds regardless the amount of microparticulate solid on the electrode. Application to a set of archaeological samples from the archaeological Roman site of Gadara (Jordan, 4th century AD) …
Electrochemical analysis of the first Polish coins using voltammetry of immobilized particles
2017
[EN] A series of 20 denarii from Boleslaus the Brave (992-1025) and Mieszko II Lambert (1025-1034), corresponding to the beginning of the Polish state were studied using the voltammetry of immobilized particles (VIMP) methodology. VIMP experiments, applied to nanosamples of the corrosion layers of the coins in contact with aqueous acetate buffer, provided well-defined responses mainly corresponding to the corrosion products of copper and lead. Such voltammetric responses, combined with X-ray fluorescence (XRF) spectroscopy experiments performed on the same set of coins, and complemented by focusing ion beam-field emission scanning electron microscope (FIB-FESEM) on silver coins from the 19t…
On-line database of voltammetric data of immobilized particles for identifying pigments and minerals in archaeometry, conservation and restoration (E…
2016
[EN] A web-based database of voltammograms is presented for characterizing artists' pigments and corrosion products of ceramic, stone and metal objects by means of the voltammetry of immobilized particles methodology. Description of the website and the database is provided. Voltammograms are, in most cases, accompanied by scanning electron microphotographs, X-ray spectra, infrared spectra acquired in attenuated total reflectance Fourier transform infrared spectroscopy mode (ATR-FTIR) and diffuse reflectance spectra in the UV-Vis-region. For illustrating the usefulness of the database two case studies involving identification of pigments and a case study describing deterioration of an archae…
Electrochemical Characterization of Corrosion Products in Leaded Bronze Sculptures Considering Ohmic Drop Effects on Tafel Analysis
2015
[EN] The characterization of corrosion products in leaded bronze based on the voltammetry of immobilized particles methodology is described. Voltammetric data, supported by Fourier transform infra-red spectroscopy, field emission scanning electron microscopy-energy dispersive X-ray microanalysis (FESEM-EDX) and scanning electrochemical microscopy (SECM) allow the identification of copper and lead corrosion materials. The mutual influence of such products is modeled upon considering uncompensated ohmic drops in the Tafel analysis of the rising portion of the respective voltammetric signals for their electrochemical reduction.