2019/04/04 by Marcos Martinón‐Torres, Xiuzhen Li, Yin Xia +11 · 1 citation
Arts and Humanities · Materials Science · Environmental Science · #Cultural Heritage Materials Analysis #Corrosion Behavior and Inhibition #Heavy metals in environment #Lacquer #Bronze #Chromium #Chromate conversion coating #Rust (programming language) #Archaeology #Metallurgy #Trachyte #Bronze Age #Materials science #Geology #Coating #Geography #Geochemistry #Computer science #Volcanic rock #Composite material
paper · pdf · doi:10.1038/s41598-019-40613-7
openalex publication_date 2019/04/04 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/31
For forty years, there has been a widely held belief that over 2,000 years ago the Chinese Qin developed an advanced chromate conversion coating technology (CCC) to prevent metal corrosion. This belief was based on the detection of chromium traces on the surface of bronze weapons buried with the Chinese Terracotta Army, and the same weapons' very good preservation. We analysed weapons, lacquer and soils from the site, and conducted experimental replications of CCC and accelerated ageing. Our results show that surface chromium presence is correlated with artefact typology and uncorrelated with bronze preservation. Furthermore we show that the lacquer used to cover warriors and certain parts of weapons is rich in chromium, and we demonstrate that chromium on the metals is contamination from nearby lacquer after burial. The chromium anti-rust treatment theory should therefore be abandoned. The good metal preservation probably results from the moderately alkaline pH and very small particle size of the burial soil, in addition to bronze composition.