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采用光学显微镜、扫描电镜、电子探针、X射线衍射、XPS等方法对银质纪念币在大气中放置出现的白斑的成份、结构进行了宏观和微观的分析检查,并结合湿热加速试验及银币生产现场情况,综合分析白斑的生成机理.结果表明:在湿润环境中,Cl~-、O_2、H_2S是导致银币表面产生白斑的主要物质;银币表面白斑腐蚀产物主要由AgCl、Ag_2O和Ag_2S构成,腐蚀产物的颜色并不随腐蚀白斑长大而改变;银币表面存在的供氧差异腐蚀电池是银币表面白斑形核、长大的主要诱因.
The microscopic and microscopic examination of the composition and structure of the white patches of silver commemorative coins placed in the atmosphere were conducted by optical microscopy, scanning electron microscopy, electron probe, X-ray diffraction, XPS and other methods. Combined with accelerated wet-heat test and silver coin The results show that Cl ~ -, O_2 and H_2S are the main substances that cause white spots on the silver surface in wet environment. The white corrosion products on silver surface mainly consist of AgCl, Ag_2O and Ag_2S, The color of the corrosion product does not change with the growth of the cornered white spots. The difference of the oxygen supply on the surface of the silver coin corrodes the battery, which is the main cause of white spot nuclei on the surface of silver coins.