Abstract:Two "black lacquer" copper mirrors of the Han Dynasty excavated from Xunyangcheng site in Jiangxi Province were studied by metallographic microscope and scanning electron microscope. The results show that the two "black lacquer" copper mirrors are both CuSn alloy + Pb, and the tin rich layer on the surface is closely connected with the substrate, and they can be divided into transition layer and non-metal layer. Compared with the bronze mirror of Han Dynasty unearthed in different areas and the bronze samples treated with humic acid, the characteristics are consistent: from the substrate to the non-metallic layer, the copper content gradually decreases, the tin content gradually increases, and the change curve is close to coincidence; The types and contents of impurity elements increase; The corrosion process is α phase preferentially corrosion; Good corrosion resistance is mainly related to tin oxide; It is found in more acidic red soil or brown soil distribution areas. The comprehensive study shows that the "black lacquer" is formed by the natural corrosion of high tin bronze in the buried environment, which has nothing to do with artificial treatment. The analysis and detection of these two copper mirrors enrich the database of "black lacquer" copper mirrors, provide more scientific basis for the natural formation of "black lacquer", and have important significance for the study of ancient metal technology and copper mirror casting technology in different regions of the Han Dynasty.