Corrosion Behavior of Simulated Bronze Relics in Acetic Acid Atmosphere

Three kinds of bronze covered with patina were prepared by electrochemical method to simulate bronze relics for corrosion test. The surface morphology and corrosion products of three kinds of patinated bronze and bare bronze after testing in acetic acid atmosphere were studied by scanning electron microscopy (SEM), X-ray diffraction (XRD) and Raman spectroscopy. The experimental results indicate that the bare bronze surface was covered by corrosion products after corrosion in acetic acid atmosphere, the corrosion products of bare brone increased with the extension of corrosion time, and mainly included Cu₂O, copper hydroxide acetate and copper acetate. The cubic crystals of Cu₂O on the surface of bronze with Cu₂O patina were destroyed and converted into acicular corrosion products. The corrosion products of the brone with Cu₂O patina were copper hydroxide acetate and copper acetate. The CuCl patina on the surface of bronze did not react with acetic acid directly, but acted with water and oxygen in the air and generated copper chloride hydroxide. The mixed patina had three rust layers, providing protective effect on the bronze substrate to some extent. The corrosion of rust layers happened at the same time, and their corrosion products were copper chloride hydroxide, copper hydroxide acetate and copper acetate.