In recent years, interest in using copper and its alloys has grown amongst architects and planners due to their favourable environmental performance. With the growing use of metals in outdoor design, some interest about how metals interact with the environment is of increasing interest. With regard to this, the European copper industry invested in research to understand how the appearance of copper based materials changes in response to different conditions.
The natural development of patina is one of copper’s unique characteristics: exposed to the outside atmosphere it protects itself by developing a patina layer over time which makes it weather resistant with a lifespan over many generations. Changes are very gradual and not entirely predictable – just like the weather, which, in turn, is solely responsible for copper’s continual changes. The prevailing concentrations of air pollution and the environmental conditions essentially determine the composition and protective properties of the patina. The interaction of the patina with the local atmospheric conditions will determine the surface appearance and how it changes over time.
Further information: Surface appearance of copper-based materials at unsheltered marine conditions - G. Herting and I. Odnevall Wallinder, Div. Surface and Corrosion Science, KTH Royal Institute of Technology, Stockholm, Sweden