硫醇对银片的腐蚀性研究

CORROSIVENESS OF THIOLS ON SILVER STRIP

一般浓度下硫醇单独存在时不会腐蚀银片 ,但与硫共存时能显著提高腐蚀程度 .硫醇与硫在腐蚀性上的协同作用实质上是与硫化银的作用 ,而在这一过程中氧的存在起着重要作用 .硫醇和硫对银片协同腐蚀的机理为 :硫首先和银片反应生成硫化银 ,硫醇吸附在硫化银表面 ,在氧气作用下 ,硫醇发生S -H键断裂 ,生成硫醇银、硫和水 。

Generally,thiols merely in oil products show little corrosivenes to silver strip.However their corrosiveness degree to silver strip may be greatly increased while co existing with elementary sulfur.Moreover,the coordinated corrosion reactions of thiols with elementary sulfur to silver strip is essentially that of thiols with silver sulfide,and oxygen plays an important role during the process.The mechanism is considered as follows.Firstly elementary sulfur reacts with silver to become silver sulfide.Then thiols are absorbed chemically to silver sulfide.With the action of oxygen,the S-H bond of thiol is broken,resulting in silver thiolate,elementary sulfur and water.Elementary sulfur turns into silver sulfide immediately.