Corrosion evolution of UNS C90300 bronze in simulated acid rain of Hong Kong

Corrosion evolutions of UNS C90300 bronzes with and without artificial patina were investigated in the simulated acid rain of Hong Kong. The corrosion products mainly composed of cuprite were formed on the surface exhibiting slight protection for the bronze substrate. The ratios of Sn and Zn in the corrosion products are lower than in the alloy. The artificial patina effectively enhances the corrosion resistance of bronze substrate, even after 30 days of immersion. For both bare and patinated bronzes the Sn- and Zn-based species are absent in the outer layers of corrosion products, and Cu₂O species in the outer layer can partially transform into Cu (II) ionic state due to the abundant supply of dissolved oxygen.