Research on effects of bird excrement on metal materials copper and bronze

0501209 - ÚTAM 2019 RIV CZ eng J - Journal Article
Balogh, K. - Slížková, Zuzana - Kreislová, Kateřina
Research on effects of bird excrement on metal materials copper and bronze.
e-Monumentica. Roč. 5, č. 1 (2017), s. 5-17
R&D Projects: GA MŠMT(CZ) LO1219
Keywords : corrosion * bird excrement * uric acid * copper * bronze
OECD category: Coating and films

The presented study was aimed at understanding the effects of bird excrement on copper and bronze. The experiment used accelerated aging tests and focused on the impact of specific chemical components of droppings (uric acid, sodium nitrate, potassium dehydrate phosphate, potassium chloride and potassium sulphate). The effects of environmental conditions (relative humidity of 100 %, SO2 pollution) and exposure duration were also studied. Pure copper sheets, copper sheets with a stable patina, as well as bronze sheets were contaminated by corrosive drops and then, after exposition, investigated. The 3D digital microscopy showed the changes in surface colour and texture. Visual evaluation showed that the drops displayed visible changes within four weeks and that there are minimal differences between RH and RH + SO2 exposure. SEM and SEM-EDS showed the change in surface texture and also identified the presence of fungi and dust particles. Overall, bird droppings do promote the corrosion process of metals. A patina can act as a protective layer against corrosion for some time before it begins to deteriorate. A longer study is required to see more developed results.
Permanent Link: http://hdl.handle.net/11104/0293202