Abstract: The composition and state of silver-electroplated deposits exposed to light of different wavelengths have been investigated using XPS and AES. The results showed: ( 1 )The phototarnishing effects of different wavelengths had the following order: 1537 A>3650 A>sunlight. ( 2 )For the same wavelength, the longer the exposure time, the more serious the phototarnishing. ( 3 )Auger parameter measurement showed that Ag2O amounted to 42.9% of the total silver after exposure for 18 hours to 2537 A ultraviolet light, and 17.6% for 24 hours. ( 4 )XPS measurement showed that the surface of the silver deposit was first oxidized and chloridized when exposed to light in the atmosphere, and the silver chloride might then be transformed into Ag2O, which was eventually reduced in ultraviolet light into black superfine silver particles and AgO. After immersing a silver deposit in a Na2S solution, the part of the deposit reexposed to air above the Na2S solution became blue in colour, while remainder part still immersed in the Na2S solution was not tarnished. From the binding energy of Ag(3d) and S(2p) and from M4 VV and M5VV Auger lines, it could be deduced that the non-tarnished silver deposit was still metallic, while the blue coloration was due to Ag2S. Thus, the tarnishing reaction in air of the silver deposit after immersion in the Na2S solution may be written as follows. 4Ag + O2 + 2H2O + 2Na2S→2Ag2S + 4NaOH

摘要： 本文用电子能谱(XPS和AES)研究了不同波长光照射后,镀银层表面膜的组成和状态的变化,结果表明:(1)光波的致变色能力按以下顺序递降2537(?)>3650(?)>日光;(2)同一波长光照射时间越长,变色愈甚;(3)应用俄歇参数方法进行表面元素价态分析,发现2537(?)照射18小时表面约有43%的银为Ag_2O,照射24小时后表面约有18%的银为AgO;(4)XPS测定表明.银层在大气中照射时,表面银先被氧化和氯化,随后氯化物可能转化为Ag_2O,最后Ag_2O被光转化为黑色的超细颗粒的银粒子和AgO.镀银层浸在Na_2S溶液中,然后将一半面积提出液面.让其露在大气中,结果浸在Na_2S液中的部分不变色,露在大气中的部分却变为蓝色.通过Ag(3d)、S(2P)结合能以及M_4VV、M_5VV俄歇峰的测定.证明未变色银表面仍为银,蓝色层则是Ag_2S.因此,镀银层浸入Na_2S溶液后在大气中的变色反应可表示为4Ag+O_2+ZH_2O+2Na_2S→2Ag_2S+4NaOH