Metals

Setup and selection of cleaning methodologies

In the case of metallic artefacts, corrosion rate can be measured by means of in situ electrochemical techniques. It is therefore possible to evaluate, for example, the effect that cleaning has on degradation rate. It is important to check that all the undesired or harmful substances are removed, preserving at the same time the protective patina of corrosion products. It is therefore crucial to select the procedure that assure the minor activation of the surface and that guarantees the highest protection offered by patinas over time. At the moment two collaborations are active in this topic: with the restorers of Aconerre for the restoration of bronze statues of the GAM (http://www.gam-milano.com); and with the restoration laboratory of the Fonderia Artistica Battaglia (http://www.fonderiabattaglia.com) for the setup of cleaning methodologies of the Cimitero Monumentale of Milan

Referente: Sara Goidanich

Measurement and monitoring of degradation rate by means of non-destructive and in situ methodologies

Measurement and monitoring by means of non-invasive or micro-destructive technologies is an important research topic for the MaMeCH laboratory. In particular, galvanic sensor have been set up for the continuous monitoring of gilded bronzes. In addition, electrochemical techniques (LPR and EIS) are used for the measurement of corrosion rate of metallic surfaces. The research work includes an experimental part related to the setup and validation of different measurement methodologies and the study of real case studies.

Referente: Sara Goidanich

  • S. Goidanich, D. Gulotta, L. Brambilla, R. Beltrami, P. Fermo and L. Toniolo, Setup of Galvanic Sensors for the Monitoring of Gilded Bronzes, Sensors, 14 (2014) 7066-7083, ISSN 1424-8220; doi:10.3390/s140407066 http://www.mdpi.com/1424-8220/14/4/7066.
Protective coatings and corrosion inhibitors

Benzotriazole (BTA) despite its toxicity is still the most frequently used corrosion inhibitor by restorers. Also in terms of protective coatings, an optimal product has not yet been identified because it is hard to combine on a single product different requirements such as: good protection, aesthetic compatibility and reversibility. The research work focuses on the testing and selection of innovative and more traditional coatings and corrosion inhibitors. The aim is to find green protective treatments. The best performing solutions will be applied on real case studies.

Contact person: Sara Goidanich

  • S. Agnoletti, L. Brambilla, A. Brini, A. Cagnini, M. Camaiti, C. Celi, L. Cetarini, R. De Lapi, M. Galeotti, S. Goidanich, S. Porcinai, B. Salvadori, L. Toniolo, Formulati e metodologie per la pulitura e la protezione di superfici metalliche, Arkos – Scienza e restauro, 28 (2011) 34-37, ISSN 1974-7950 Arkos
  • S. Goidanich, L. Toniolo, I. Odnevall Wallinder, Effects of wax-based anti-graffiti on copper patina composition and dissolution during 4 years of outdoor urban exposure, Journal of Cultural Heritage, 11 (2010), 288-296, ISSN: 1296-2074, doi:10.1016/j.culher.2010.02.001 http://www.sciencedirect.com/science/article/pii/S129620741000018X
Monitoring and conservation of Ghiberti’s Porta del Paradiso

TThe project was initially related to the selection of the optimal solution for the exposition to the public of the Porta del Paradiso. Thank you to the use of galvanic sensors, which simulate the actual artefact in terms of composition and stratigraphy, it was possible to evaluate that a showcase with low and controlled relative humidity could assure the same level of protection of a showcase saturated with nitrogen. Galvanic sensors have been also used to monitor the corrosion rate of the Porta del Paradiso inside its showcase for three years. (Project concluded in 2014)

Contact person: Sara Goidanich

  • S. Goidanich et al., Corrosion Evaluation of Ghiberti’s “Porta Del Paradiso” in Three Display Environments, in Proceedings of Metal 2010, International Conference on Metal Conservation, Interim meeting of the international council of museums committee for conservation metal working group, October 11-15, Charleston, South Carolina, USA, 151-159, 2010, ISBN 978-0-9830399-0-7
  • Andrea Cagnini, Simone Porcinai, Roberto Boddi, Laura Brambilla, Sara Goidanich, Alessandra Bonazza, Monitoraggio all’interno della vetrina, in Il Paradiso ritrovato – Il restauro della Porta del Ghiberti, p. 341-345, a cura di Annamaria Giusti, ed. Mandragora s.r.l., 2015, ISBN 978-88-7461-247-5
  • https://sites.google.com/site/bronzidoratiprin2009/
Atmospheric corrosion of copper alloys

The project, coordinated by the KTH of Stockholm (Prof. I. Odnevall Wallinder) and funded by the European Copper Institute, is aimed at the study of the degradation processes of copper based alloys exposed outdoor and involves the exposition of samples in several European sites. Particular attention is paid to the impact of environmental conditions on corrosion, runoff, development and characterization of patinas. (Project concluded in 2015)

Contact person: Sara Goidanich

  • Y. S. Hedberg, J. F. Hedberg, G. Herting, S. Goidanich, and I. Odnevall Wallinder, Critical review: Copper runoff from outdoor copper surfaces at atmospheric conditions, Environ. Sci. Technol., 48 (2014), 1372−1381, doi 10.1021/es404410s http://pubs.acs.org/doi/abs/10.1021/es404410s
  • Odnevall Wallinder, X. Zhang, S. Goidanich, N. Le Bozec, G. Herting, and C. Leygraf, Corrosion and runoff rates of Cu and three Cu-alloys in marine environments with increasing chloride deposition rate, Science of the Total Environment, 472, (2014), ISSN: 0048-9697, 681–694, DOI: http://dx.doi.org/10.1016/j.scitotenv.2013.11.080
  • S. Goidanich, J. Brunk, G. Herting, M.A. Arenas, I. Odnevall Wallinder, Atmospheric corrosion of brass in outdoor applications. Patina evolution, metal release and aesthetic appearance at urban exposure conditions, Science of the Total Environment, 412-413, (2011), 46-57, ISSN: 0048-9697, DOI: 10.1016/j.scitotenv.2011.09.083 http://www.sciencedirect.com/science/article/pii/S0048969713013636