2-巯基苯并噻唑对铜缓蚀行为的表面增强红外光谱研究

2-巯基苯并噻唑(MBT)是Cu的高效缓蚀剂,但是缓蚀机理存在较大争议.本文通过电化学极化曲线从宏观角度对缓蚀效率进行评估,并利用原位衰减全反射-表面增强红外光谱技术结合理论计算研究了电位控制下的微观吸附构型.结果表明:在较高电位(大于0 V,相对饱和甘汞电极(SCE))下,MBT和金属Cu之间发生电子转移,MBT以硫醇式的环外S和N与金属Cu(I)离子配位在表面形成聚合物膜;在较低电位(小于0 V,vs SCE)下,MBT通过环外S原子以硫醇离子形式在金属Cu表面直立吸附.表面膜阻止了腐蚀介质的侵蚀,起到了较好的缓蚀效果.

Surface-Enhanced Infrared Absorption Spectroscopy Study of Anticorrosion Behavior of 2-Mercaptobenzothiazole on Copper

2-Mercaptobenzothiazole (MBT) is a highly efficient inhibitor of Cu. However, the inhibition mechanism is still unclear. In this paper, the anticorrosive effect of MBT on a Cu surface at the macroscopic level was evaluated using a polarization curve technique. The potential-dependent adsorption geometries of MBT at the molecular level were investigated using electrochemical surface-enhanced infrared reflection absorption spectroscopy in attenuated total reflection mode, together with theoretical calculations. The results indicated that the MBT molecules were adsorbed on the Cu surface vertically, in a thiolate form, through exocyclic S atoms at a potential negative of 0 V (vs saturated calomel electrode (SCE)). At a potential positive of 0 V (vs SCE), electrons were transferred between MBT and the Cu substrate, meaning that MBT molecules can interact with the Cu surface via exocyclic S and endocyclic N atoms to form a polymer film, resulting in the formation of a compact protecting layer to prevent Cu dissolution.