Research Trends

Raman microspectroscopy, X-ray photoelectron spectroscopy (XPS) and X-ray energy dispersive spectroscopy (EDS) were used to identify the matrix elements near the surface and components of the verdigris of an ancient Chinese copper coin Sui wuzhu which was excavated in Shanxi province of China. The main components of surface corrosion products included CuCO₃·Cu(OH)₂ with small amounts of Cu₂O, CuPbSO₄(OH)₂, PbCO₃ and PbO. The matrix elements included copper, lead and carbon with small amounts of iron, oxygen and sulfur. The amount of copper is higher than that of lead, although the total amount of the two is less than forty percent. The results are of great importance not only to the identification of Chinese ancient copper coins, but also to the ancient Chinese casting technology and chemical refining. Moreover, the study offers significant fundamental information to the research on the influence of heavy metal on the health of ancient coin users.