ABSTRACT
ABSTRACT: We present results on the design of environmental trials that simulate the weathering process of metal of our heritage on marine, urban and archeological environments. With this proposal, the laboratory tests have been performed to evaluate metal response on different controlled environments: contaminated urban atmosphere, seacoast conditions due to marine aerosol and immersion or total or partial burial on earth. This study has been applied on three different metals: copper, brass and iron. The samples were cut in sheets of 5 × 5 cm and 1-2 mm of thickness. The laboratory experiments have allowed analyzing the physical-mechanical behaviours and the durability of metals against the effects of outside agents. The found weathering forms depend on chemical composition and the degree of damage is associated to the complex system metal-environment. The results are similar to the main metal pathologies on urban, archeological and marine conditions: uniform corrosion, pitting and dezincification. For the diagnosis, damage extensions have been assessed by the following techniques: gravimetric control, Optical Microscopy OM, X-Ray Diffraction (XRD), and Scanning Electron Microscopy coupled to Energy Dispersive X-ray spectroscopy (SEM-EDX). The corrosion process is homogeneously extended at urban and marine environments (immersion) in the three alloys, while trials of marine environment (spray) and burial mainly show pitting. Brass samples present dezincification zones. Most hazardous conditions are urban environment, while samples buried (total or partial) shows less extensions and levels of corrosion. In sum, these short term trials are a simplification of long-term weathering process. The results are useful to reproduce the weathering forms of our heritage and as models of metal behaviour on marine, urban environment and archeological conditions.
