Fast Dating of Yongzheng Copper Coins in Tsing Empire by SEM-EDS

摘要

Twenty Yongzheng copper coins were fast dating by X-ray energy dispersive spectrometer with scanning electron microscope (SEM-EDS) according to official ingredient. The 20 coins were classified in two groups according to the results. Group 1 represents the coins minted before AD 1 728 and group 2 represents the coins minted after AD 1 728. At concentration range (0. 00%-5. 13%) , the distribution of lead is not homogeneous in the coins, and the largest diameter of lead inclusion is less than 15 μm.The official fineness degrade is supported.