Corrosion Characteristics and Conservation Measures of the Tang Dynasty Bronze Mirror with Auspicious Beast Motifs

The corrosion characteristics of a Tang Dynasty bronze mirror with auspicious beast motifs were systematically investigated using X-ray flaw detectors, scanning electron microscopy energy dispersive spectroscopy (SEM-EDS), optical microscopey, and Raman spectrometers to analyze its substrate composition and corrosion products. The results show that during long-term burial, a multilayer corrosion structure gradually formed from the surface inward. The surface corrosion products mainly consisted of Cu₂(OH)₂CO₃, Cu₂(OH)₃Cl, and trace amounts of PbSO₄. The substrate metal exhibited distinct phase-selective corrosion, where lead and (α+δ) eutectoid were preferentially corroded compared to the α phase. This corrosion characteristic showed a significant correlation with its burial environment. Based on the analysis of corrosion characteristics, conservation and restoration recommendations were proposed for the bronze mirror.