Hu Pei, Jia Minghao, Xu Hao, Zhang Xiaogu, Hu Dongbo, Hu Gang
School of Archaeology and Museology, Peking University, Beijing 100871, China.
The Palace Museum, Beijing 100009, China.
Materials (Basel). 2023 Mar 8;16(6):2180. doi: 10.3390/ma16062180.
Ancient iron artifacts need to be protected with a rust layer, often stabilized by tannic acid corrosion inhibition. In humid environments, water vapor could slowly penetrate and trigger galvanic corrosion of metal artefacts. Sealing treatments are generally applied to the artefact surface to isolate water and enhance its corrosion resistance. Superhydrophobic modifications could effectively block the penetration of moisture into the interior of the artefact and provide a nice water barrier. Stearic acid with tannic acid inhibition treatment creates a superhydrophobic protective layer on the surface of rusted iron artifacts and enhances corrosion resistance effectively. Various scientific analyses and testing methods are used in this paper to evaluate the corrosion resistance of rusted surfaces after superhydrophobic modification and investigate the reaction mechanisms. The results indicate that the contact angle of the rusted surface after corrosion inhibition by tannic acid and modified by stearic acid is increased to 152.2°, which means the superhydrophobic protective layer has been successfully constructed. The C/Fe ratio of the rusted surface is increased from 0.21 to 2.10, and the characteristic diffraction peaks of O1s and Fe 2p shift toward higher binding energy. Stearic acid is combined with the corrosion product layer by chemical bonding. Chelation between rust products, tannic acid, and steric acid is effective, and the chelate is chemically stable. The superhydrophobic surface forms a lamellar wax-like layer as an air barrier to isolate liquid water, resulting in a significant decrease in corrosion current and an increase in Warburg impedance to 217.9 times the original state, with a protection efficiency of 88.3%. Tannic acid corrosion inhibition and stearic acid superhydrophobic modification have an excellent synergistic protective effect on improving the corrosion resistance of iron artifacts, resulting in better corrosion resistance of iron artifact materials. The research provides new ideas and references for the protection of ancient iron artifacts sealing.
古代铁制文物需要用锈层进行保护，锈层通常通过单宁酸缓蚀作用来稳定。在潮湿环境中，水蒸气可能会缓慢渗透并引发金属文物的电偶腐蚀。通常会对文物表面进行密封处理，以隔绝水分并增强其耐腐蚀性。超疏水改性可以有效阻止水分渗透到文物内部，并提供良好的防水屏障。硬脂酸与单宁酸缓蚀处理在生锈铁制文物表面形成超疏水保护层，有效提高耐腐蚀性。本文采用多种科学分析和测试方法来评估超疏水改性后生锈表面的耐腐蚀性，并研究反应机理。结果表明，经单宁酸缓蚀和硬脂酸改性后的生锈表面接触角增大到152.2°，这意味着超疏水保护层已成功构建。生锈表面的C/Fe比从0.21增加到2.10，O1s和Fe 2p的特征衍射峰向更高结合能方向移动。硬脂酸通过化学键与腐蚀产物层结合。锈产物、单宁酸和硬脂酸之间的螯合作用有效，且螯合物化学性质稳定。超疏水表面形成层状蜡状层作为空气屏障以隔离液态水，导致腐蚀电流显著降低，Warburg阻抗增加到原始状态的217.9倍，保护效率为88.3%。单宁酸缓蚀和硬脂酸超疏水改性对提高铁制文物的耐腐蚀性具有优异的协同保护作用，使铁制文物材料具有更好的耐腐蚀性。该研究为古代铁制文物密封保护提供了新的思路和参考。
