The purpose of this paper is to investigate the microstructures, slag inclusions, morphology and composition of ancient Chinese iron coins exhumed from Emei Mountain and Baoji after 818‐966 years of being imbedded underground.
Metallography, scanning electron microscopy, energy dispersive spectrometry, X‐ray photoelectron spectrometry and Fourier transform infrared spectroscopy were employed.
The results showed that archaeological coins exhibited characteristics of a typical hypoeutectic white cast iron, with slag inclusions of FeS strips and phosphate. Porous or hexagonal platey corrosion products were discovered on the archaeological iron coin, which were mainly identified as Fe2O3, FeOOH, Fex(OH)1−xCO3 and Fex(OH)1−xSO4. The possible corrosion mechanisms for the iron coins were discussed based on the corrosion products.
This study revealed the characterization of corrosion products on archaeological iron coins and may provide guidance for the preservation of archaeological iron.
