Desalting Protection of Iron Artifacts Unearthed in the Three Gorges Area of Chongqing

The morphology and composition of the corrosion products of a batch of Han Dynasty iron artifacts unearthed in the Three Gorges area of Chongqing were analyzed by scanning electron microscopy, energy dispersive spectrometer and X-ray diffractometer. The desalination process of iron artifacts in deionized water and deionized water solution with 0.5 mol/L NaOH was dynamically monitored by chloride ion selective electrode. The results showed that the corrosion products of the iron artifacts were mainly composed of α-FeOOH, Fe₃O₄, SiO₂, NaAlSi₃O₈, and some iron artifacts contained a small amount of chlorine. In deionized water and deionized water solution containing 0.5 mol/L NaOH, after soaking for about 150 h, the chloride ion content in the solution did not change significantly with the extension of time, basically lower than 2 mg/L, and the desalination cycle was much lower than other iron artifacts with high chloride content (iron artifacts unearthed from the sea).