A mechanism study of type i corrosion on the surface of ancient tin rich bronzes

Abstract This study compares the surface patina of ancient tin rich bronze with pure hydrothermally synthesized SnO 2 nanoparticles using various analytical techniques, including metallographic microscopy, scanning electron microscopy, transmission electron microscopy, energy dispersive spectroscopy, X-ray diffraction, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and high-angle annular dark-field scanning transmission electron microscopy. The primary crystalline component of the patina consists of approximately 5 nm SnO 2 nanoparticles, which closely resemble pure SnO 2 , indicating their comparability. Cu was also detected in the patina; however, it did not form crystalline structures. The X-ray diffraction results showed a shift in the patina’s peak, suggesting the infiltration of Cu into the SnO 2 lattice, which compromises its crystallinity. In comparison to synthetic SnO 2 , the X-ray photoelectron spectroscopy spectra of the patina revealed novel peaks corresponding to both Cu and O, indicating the presence of Cu−O−Sn bonding—a characteristic feature of type-I patina. This suggests that the primary structure of type-I patina consists of crystalline SnO 2 nanoparticles, with a limited amount of Cu integrated into its lattice configuration. The concentration of Cu within the SnO 2 crystal units is restricted, leading primarily to the formation of amorphous Cu 2 O in conjunction with Sn. The presence of Sn enhances the structural stability of Cu 2 O, facilitating its incorporation while inhibiting the crystallization of Cu 2 O. However, when the Sn concentration is insufficient, an inadequate Cu–O−Sn amorphous phase may form, allowing for the potential crystallization of Cu 2 O.