Struggle against corrosion:protection by triazoles compounds of ancient and modern bronzes covered with patina

摘要

Bronzes objects belonging to archaeological or cultural heritage are numerous and often exposed at museums or in the street covered with patina at their surface.Unfortunately,these artefacts suffer nowadays a significant corrosion degradation due namely to increasing of pollution level though the patina layer itself protects partially the substrate metal or alloy.As for example,we will show the protection of archaeological bronze coins covered with patina,discovered in Morocco,by triazole derivatives:benzotriazole,bi-triazole,and amino-triazole.On one of the coins covered with green patina,the elemental composition of patina and also that of the substrate alloy were determined first.Then,the inhibiting effect of these compounds to the artificial patina scraped off from modern bronze of similar alloy composition was evaluated by a cavity microelectrode.Finally,on three coins covered with the patina of different colours,the inhibiting effectiveness was evaluated.It appeared that the amino-triazole is the most interesting substance among these three examined compounds.