α-CuSn bronzes in sulphate medium: Influence of the tin content on corrosion processes

Corrosion of synthetic CuSn bronzes was electrochemically investigated on rotating disc electrode (RDE) in a buffered medium (pH = 6.8, deaerated 10-2 mol L−1 Na2SO4 solution). Copper species diffusion coefficients through the patina for various tin-content bonzes were analyzed and provided information about its organization. A joined mass-transport and electronic transfer process controls the corrosion. A faster and more efficient passivation was observed with highest bronze tin-content. Also, copper species diffusion through the layer is independent of the tin content and few 10−10 cm2 s−1. Such an order of magnitude indicates that corrosion products layer behaves like a gel.