Gold Leaf Corrosion in Moisture Acid Atmosphere at Ambient Temperature

摘要:

近年来许多贴金文物损坏严重。将金箔暴露于潮湿的SO2、NO2及其混合模拟气氛中以研究其在室温环境气氛中腐蚀的可能性。与金在室温下仅在王水中腐蚀的常识不同，金箔在这3种气体里都发生了腐蚀。在潮湿的SO2气氛中，金箔腐蚀的主要原因是杂质铜的优先氧化。在潮湿的NO2气氛和SO2与NO2的混合气氛中，金箔腐蚀的主要原因是杂质的优先氧化结合金本身的氧化。其中金的氧化是由于其加工过程中大的冷加工变形导致的高缺陷密度。金在室温下酸性气氛中腐蚀现象的发现不仅扩展了对金的性能的理解，还对贴金文物和艺术品的保护提供了有益的指导

Abstract:

Many cultural relics adhered with gold leaf (e.g. gold foil) are found damaged seriously in recent years. In this paper, gold leaf was exposed in the imitating atmosphere of moisture SO2, NO2 and their mixture to investigate its corrosion possibility in environment atmosphere at ambient temperature. Following phenomena were observed. The gold leaf was corroded in all these three atmospheres, which is contrary to the common sense that gold can only be corroded in aqua regia at ambient temperature. In SO2 atmosphere, the main reason of the corrosion is the preferential oxidation of the impurity of Cu. In the atmospheres of NO2 and the mixture of SO2 and NO2, the main reason of the corrosion is the combination of the preferential oxidation of the impurity and the oxidation of gold itself caused by the high defect density stemmed from the severe cold deformation during its processing. The discovery that gold can be corroded in moisture acid atmosphere at ambient temperature expands the understanding of the character of gold, and provides beneficial guidance to the protection of culture relics and modern artworks decorated with gold foil