A 3-mercapto-propyl-trimethoxysilane coating (PropS-SH) applied on Cu-Si-Mn bronze, patinated by “liver of sulphur” was investigated as a non-toxic alternative to Incralac®, usually applied on outdoor artistic bronzes. Electrochemical testing was performed in synthetic acid rain. Exposure to temperature/UV cycles and accelerated corrosion test simulating unsheltered exposure to rainwater was also carried out. The exposed samples were characterised by FEG-SEM coupled with EDS on FIB cross-sections and XPS on free surfaces. The black patina without protective coating was scarcely protective against bronze corrosion and easily transformed into cuprous oxide. PropS-SH coating fully preserved the black patina microstructure and phase constituents (cuprous oxide and cuprous sulphide). The PropS-SH coating also resulted more protective than Incralac® when aged under run-off conditions. Selective dissolution of copper from the silicon bronze alloy was observed on both uncoated and Incralac®-coated bronze, leading to the formation of an internal Si-rich corrosion layer.
Evaluation of the protectiveness of an organosilane coating on patinated Cu-Si-Mn bronze for contemporary art / Masi, G.*; Josse, C.; Esvan, J.; Chiavari, C.; Bernardi, E.; Martini, C.; Bignozzi, M.C.; Monticelli, C.; Zanotto, F.; Balbo, A.; Svara Fabjan, E.; Kosec, T.; Robbiola, L.. - In: PROGRESS IN ORGANIC COATINGS. - ISSN 0300-9440. - STAMPA. - 127:(2019), pp. 286-299. [10.1016/j.porgcoat.2018.11.027]
Evaluation of the protectiveness of an organosilane coating on patinated Cu-Si-Mn bronze for contemporary art
Masi, G.;Chiavari, C.;Bernardi, E.;Martini, C.;Bignozzi, M. C.;
2019
Abstract
A 3-mercapto-propyl-trimethoxysilane coating (PropS-SH) applied on Cu-Si-Mn bronze, patinated by “liver of sulphur” was investigated as a non-toxic alternative to Incralac®, usually applied on outdoor artistic bronzes. Electrochemical testing was performed in synthetic acid rain. Exposure to temperature/UV cycles and accelerated corrosion test simulating unsheltered exposure to rainwater was also carried out. The exposed samples were characterised by FEG-SEM coupled with EDS on FIB cross-sections and XPS on free surfaces. The black patina without protective coating was scarcely protective against bronze corrosion and easily transformed into cuprous oxide. PropS-SH coating fully preserved the black patina microstructure and phase constituents (cuprous oxide and cuprous sulphide). The PropS-SH coating also resulted more protective than Incralac® when aged under run-off conditions. Selective dissolution of copper from the silicon bronze alloy was observed on both uncoated and Incralac®-coated bronze, leading to the formation of an internal Si-rich corrosion layer.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.