| Popis: |
Artistic bronzes are usually very heterogeneous exposed to different corrosive pollutants, especially in urban areas, and thus corrode easily forming various corrosion products [1, 2]. Depending on the corrosive environment, time of exposure, alloy composition, casting technology or prepatination various corrosion layers (patinas) form on bronze sculptures. Knowledge on patina constituent phases and the mechanisms of their formation plays an essential role in understanding the deterioration of bronzes. We have previously investigated corrosion products on bronze in various simulated types of corrosive environments by means of a series of complementary analytical and electro-analytical techniques [3- 5]. In the present study cyclic voltammetry of micro / nanoparticles (CVMP) attached to a carbon paste electrode (CPE) has been applied. The cyclic voltammetry technique with carbon-paste electrode can be ideal technique to characterize the patina layer alone and, as the total amount of the material necessary for this measurement is negligible, this method has great potential in analysis of cultural heritage artifacts [5-7]. Several bronze sculptures, each from different period, exposed to outdoor atmosphere in Zagreb city center were examined. The oldest examined sculptures were “Zdenac života”by Ivan Meštrović (1905.) and “Sveti Juraj ubija zmaja” by Anton Dominik Fernkorn (1908.). Following were WWII sculptures “Strijeljanje talaca” by Fran Kršinić (1951.) and Vladimir Nazor by Stjepan Gračan (1972.) The most recent sculptures were “Fra Grga Martić” by Mladen Mikulin (1994.), then sculpture of poet Marko Marulić by Vlade Radas exposed to urban environment in 1999, and “Igra srebra materina” by Lujo Lozica exposed in 2015. Comparison to the ATR-FTIR results revealed that the methods are complementary and that their simultaneous application could make this method attractive for wide application in conservation/restoration science due to experimental simplicity and sampling in micro to nanoscale. |
