CORROSION AND CONSERVATION OF A BIG BRONZE MIRROR IN MING DYNASTY

Scanning electron microscopy(SEM) and X-ray diffraction(XRD) were employed to analyze the composition and structure of the powdery patina of a big Ming Dynasty bronze mirror.The composition of the patina was mainly Cu3(SO4)(OH)4 ,which was the matter corroded by SO2 in polluted air.But the common patina such as CuCO3·Cu(OH)2,2CuCO3·Cu(OH)2 and Cu2(OH)3Cl were not found.These indicated that SO2 affected seriously bronze wares in the Chongqing area.Some appropriate conservation measures were suggested.