Effetto di pulitura e biopassivazione su acciaio Corten

The increased sensitivity towards environmental issues has led to a growing research interest in sustainable approaches to heritage conservation. In the last ten years, a biopassivation treatment for corroded metal surfaces has been developed in Switzerland by exploiting the natural ability of some microorganisms to form metal oxalates [1-3]. In this work, different weathering steels belonging to the same family (Corten A), characterized by different exposure histories, were first cleaned and then biopassivated with Beauveria bassiana fungal strain. The main aim was to produce a protective patina in a shorter time than natural exposure. The cleaning was intended to remove loose and/or powdery corrosion products and had a positive effect on the corrosion resistance, which improved slightly. Regarding the biopassivation procedure, despite the strong surface heterogeneity after the treatment, some very promising results emerged from the comparison of the electrochemical measurements before and after the treatment.