Copper and copper alloys, such as bronze, undergo spontaneous oxidation in humid air with a process called natural patination. In the environment containing aggressive ions, like chlorides, sulphides and nitrates, secondary corrosion takes place. Patination can be achieved also by artificial application of different chemicals achieving different textures and colours. The main aim of the present paper is to present two different statues in marine and urban environment and their corrosion products that have formed during atmosphere exposure. Raman analysis included detailed analysis of different parts of statues revealing different minerals that have formed during exposure. In marine environment atacamite was found, as well as non-crystalline cuprite and cuprous sulphide next to PM and other pollutants. In urban atmosphere brochantite and antlerite were found, cuprous oxide and a remaining of brown artist’s patination. By Raman analysis it was also shown that BTA and MBI inhibitor formed a chemical bond with bronze and oxidized bronze surface, whereas TMI did not form a chemical bond. These observations were confirmed by electrochemical tests which showed that formation of chemical bonds at the surface of bronze offers a better protection than physical bond, as observed from the change in corrosion current densities.
COBISS.SI-ID: 2407783
Description: A multi-component fluoropolymer based coating for the protection of bronze patina was developed. In order to provide various functionalities of the coating (such as the hydrophobicity of the coating surface, obtaining interactions within the coating itself as well as a bronze substrate and inhibiting the corrosion processes), a fluoroacrylate coating with appropriate adhesion promoter was suggested, with and without a silane modified benzotriazole inhibitor. The protective efficiency and durability of the applied coatings were investigated electrochemically using potentiodynamic tests and electrochemical impedance spectroscopy in a simulated acid rain solution. All of the developed coatings showed a significant decrease in the corrosion current density. The self-assembled single layer coating (FA-MS) also showed 100 % inhibition efficiency. After ageing the coating remained transparent and did not change by UV exposure and/or thermal cycling. The patina and coating investigations using FIB-SEM and EDX showed that the latter coating (FA-MS) successfully covered the surface of the patinated bronze. The mechanism of the bonding was proposed and supported with the spectroscopic observation of a thin and even coating.
COBISS.SI-ID: 2430055
The objective of this work was to test the suitability of capillary electrophoresis for determination of rain water chemical composition. The fully functional, open-hardware, low-cost instrument was assembled and tested. An original protocol for determination of the chemical content of rain water was established and validated in the pilot test. Capillary electrophoresis proofed its highest suitability for the detection and quantification of ions in different samples, indicating substantial differences between clean and dirty snow waters. The hydrostatic sample injection method has been found very efficient and straightforward in manual and laboratory routines. An important deliverable of the was a set of multimedia materials for the promotion of CE technique and especially low-cost CE instrumentation.
COBISS.SI-ID: 1541432772