Scientific Reports· 2019Q1
Surface chromium on Terracotta Army bronze weapons is neither an ancient anti-rust treatment nor the reason for their good preservation
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- Q1SCImago
- 2019year
Short summary
Analysis of Terracotta Army bronze weapons reveals that surface chromium is not an ancient anti-rust treatment but rather contamination from chromium-rich lacquer applied to the artifacts, which leached into the metal after burial.
AI-generated from the title and abstract; the full text is not read.
Key points
- Surface chromium on Terracotta Army bronze weapons is not an ancient anti-rust treatment.
- Chromium detected on weapons originates from contamination by chromium-rich lacquer applied to artifacts.
- The lacquer leached chromium into the bronze after burial, not applied as a protective coating.
- Good preservation is likely due to soil pH, soil particle size, and bronze composition, not chromium treatment.
AI-generated from the title and abstract; the full text is not read.
Abstract
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.
The authors' abstract, as published at the source. Scientific Reports, 2019 · DOI ↗
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Field: Archeology (Arts and Humanities)
ArcheologyArts and Humanities