Márcia Vilarigues is Assistant Professor at the Conservation Department of FCT, NOVA University of Lisbon. She works in the field of Conservation and Restoration of Cultural Heritage in the area of Technical Art History and Materials Degradation. Her research motivation focusses on the preservation of our material cultural history and on enriching the knowledge of our shared past through the history of historical objects. Since 2011, Márcia Vilarigues is the Director of the Research Unit VICARTE – Vidro e Cerâmica para as Artes (Glass and Ceramic for the Arts).
Potash glass corrosion and the effect of the addition of iron, copper and manganese
Dep Conservation and Restoration and Research Unit VICARTE, FCT NOVA, Campus de Caparica, 2829-516 Caparica, Portugal
In this work the corrosion processes of potash-glass surfaces in contact with aqueous solutions were studied using ion beam spectroscopic techniques, optical microscopy (OM) and Fourier transform infra-red (FTIR) spectroscopy. In order to follow the corrosion progress these surface studies were combined with the evaluation of the changes taking place in the aqueous solution. In particular, the hydrogen profiles obtained from the attacked surface region of glass were compared with the variation of pH values of the aqueous solutions, in order to extract information about the ion exchange processes. It is shown that pH values may also be a good parameter for studying corrosion kinetics in high humidity conditions.
The corrosion products of potash-glass with manganese, iron and copper ions were studied. A silica-rich-layer and calcium carbonate were identified on the surface. It was also detected that more than one silica-rich-layer has developed during the longer immersion periods. The elemental profiles for Si, K, Ca, Cu, Mn and Fe were obtained by means of Rutherford Backscattering Spectrometry in the attacked surface region of the glass, while hydrogen profiles were obtained by Elastic Recoil Detection. It is shown that a layer forms that is richer in the transition elements and that copper containing glasses displayed faster initial glass corrosion.