The Research On Corrosion Behavior Of Bronze Covered With Patina In The Environment Simulated Solutions

Bronze cultural relic is precious historical heritage, which is the basis of research on the development of human history, culture, art, and metal smelting and so on. Due to increasing air pollution, research on corrosion behavior and mechanism of bronze relics in different atmospheric environment have important theoretical and practical significance. The existing research on corrosion mechanism generally used no patinated bronze material. However, the surface of bronze relics in museum actually covered complex corrosion layers, the paper used patinated bronze which can more close to the real state of cultural relics in museum.To study the corrosion behavior and protection of patinated bronze in three kinds of environment simulated solution, firstly, three kinds of patina bronzes were made by electrochemical method, and then measured OCP, EIS and dynamic potential polarization of them and bare bronze in three kinds of environment simulated solutions, finally used SEM-EDS to analyze corrosion product after polarization.Open circuit potential experiment shows that the thermodynamic stability of Cu2O patinated bronze is best in all three kinds of environment simulated solution, bare bronze is worst; the OCP in SO2 environment simulated solution is the most negative, in atmospheric environment simulated solution is the most positive. Potentiodynamic scanning experiment shows that icorr of bare bronze is smallest. In the marine environment simulated solution, icorr of patinated bronze samples are all slightly larger than bare bronze; icorr of four samples in SO2 environment simulated solution are all less than in atmospheric environment simulated solution.EIS tests shows that in the atmospheric environment simulated solution, the inhibition property of bare bronze at early corrosion is best, but the Rp at the middle of the corrosion is the smallest which states that patinated bronze samples all play a protective role. In the marine environment simulated solution, only the Rp of Cu2O and mixed patinated bronze at early corrosion is larger than bare bronze, which shows that they are protective to bronze substrate, at the middle of the corrosion, Cu2O bronze have no protectiveness any longer; In the SO2 environment simulated solution, the Rp at early corrosion of three kinds of patinated bronze are less than bare bronze, which shows the rust layers have no protectiveness, the Rp of bare, Cu2O and mixed bronze at the middle of the corrosion diminish, in contrast to the situation in the atmospheric and marine environment simulated solution. Surface analysis shows that samples in the marine environment simulated solution are more serious than in atmospheric environment simulated solution; Samples in SO2 environment simulated solution are less serious than in atmospheric environment simulated solution, meanwhile the surface does not appear light green powder product, which testifies the addition of SO32- inhibits the powdery rust happened, in other words, SO32- and Cl-have reverse synergistic effect. In addition, bare, CuCl and mixed patinated bronze all appeared pitting phenomenon.