Abstract: Methods of SEM, EPM, Micro-XRDand XFSare employed to detect the composition and structure of micro-regions in a piece of sereously corroded bronze mirror which was made in the East-Han Dynasty of China. The analysis of section indicates that:(1) the segregation of the bronze alloy during casting is the internal reason of its electro-chemical corrosion; (2) the copper corrosion forms step by step; (3) element Cl corrodes the alloy from the surface to the deep part of the matrix; (4) during corroding element Cu diffuses from the internal alloy to outside. In the present work, the process of chemical reactions at each stage of bronze corrosion is investigated, and simulated experiments are performed. The theory of phase-equilibrium, the principle of electro-chemical corrosion and the chemical thermodynamics are applied. The results of the work provide some reference for the corrosion of alloyes, and for the protection of the ancient bronze relics.

Key words: Electron probe micro-analysis(EPMA), Micro-region X-ray diffraction (micro-XRD), Disproportionation reaction, Element diffusion, Vicious circle