A new application of Fiber optics reflection spectroscopy (FORS): Identification of “bronze disease” induced corrosion products on ancient bronzes

Abstract Fiber Optics Reflectance Spectroscopy (FORS) has been widely used in the field of cultural heritage for material identification. Nevertheless, it had been rarely applied in the study of bronze corrosion products. This paper aims at exploring the potential of FORS on corrosion products analysis, proposing it as an innovative non-destructive technique for the condition assessment of bronze artefacts in museum collections. A gilded bronze statue “Vajrasattva Bodhisattva” dated to the Ming dynasty (A. D. 1368-1644) from National Museum of China was investigated. The in-situ FORS analysis was conducted on 36 points, revealing copper trihydroxychloride (atacamite/clinoatacamite) and chalconatronite as two major types of corrosion products. This result was double-confirmed by Raman and XRD analyses of 10 samples taken from these points. It proves that FORS is a very promising technique for non-destructive in-situ detection of chloride-bearing bronze corrosions. It may revolutionize the way of screening artefacts with bronze disease, helping conservators get the distribution “map” of different bronze corrosion quickly and comprehensively, and making appropriate treatment proposals accordingly.