Corrosion behaviour of lead bronze from the Western Zhou Dynasty in an archaeological-soil medium

The corrosion behaviour of Cu-Sn-Pb bronze alloys in an archaeological-soil medium was examined using electrochemical measurements, microscopy observations and X-ray photoelectron spectroscopy analyses. The corrosion mechanism was mainly composed of the spontaneous dissolution of the base alloy and the formation of surface corrosion products. Results showed that the corrosion rate decreased with increasing Cu content, and the 79.81Cu-Sn-Pb has the lowest corrosion rate among four bronzes examined in this study. The corrosion products of the alloy consisted of two layers, an outer layer of copper, lead oxides and metal chlorides and sulphates, and an inner layer filled with Sn products.