Same site, different corrosion phenomena caused by chloride: The effect of the archaeological context on bronzes from Sujialong Cemetery, China

Abstract The corrosion of archaeological bronzes is a complex process, and different corrosion phenomena can occur even within the same site, while previous studies paid little attention. Different corrosion phenomena can be observed on bronzes unearthed from Sujialong Cemetery, Hubei, China; in particular, some bronzes exhibit severe bronze disease, which is an uncommon phenomenon in Hubei bronzes. Multiple analysis methods were used to identify the corrosion products on the bronzes and to clarify the corrosion mechanisms. The results showed that the different corrosion phenomena were associated with the tomb microenvironment in different areas of the cemetery, which was confirmed by a spatial analysis of the whole cemetery; the outbreak of bronze disease was closely related to the presence of high chloride ion concentrations in the tomb environment and poor preservation conditions after excavation. The different corrosion phenomena are related to the archaeological contexts of the bronzes (especially microenvironments), which have been investigated only superficially in the past.