ToF-SIMS study of official seals from Han Dynasty

Chinese bronze is a copper alloy containing copper, zinc, tin, lead, and other elements. ToF-SIMS has been used in the study of cultural heritage to establish authenticity, dating, origin, and the degradation process. In this study, static and dynamic SIMS was used to gain information regarding the surface composition and the depth distribution of important elements for a bronze lion and an official seal claimed as the Han Dynasty artifact (206 BC-220 AD). The results revealed that anticorrosion properties of surface layers exhibited were due to the higher percentage of nickel, but the major elements in the bulk of the artifact were copper and zinc. Surface enrichment of Au accords with the ancient Liujin method of developing a gold coating on metal object. These unique results demonstrated that ToF-SIMS is a potential tool to reveal processing methods for the ancient official seal.