采用电化学阻抗谱、极化曲线、量子化学和分子动力学, 研究了谷氨酸、焦谷氨酰胺、焦谷氨酸三种自组装膜在0.5 mol/L硫酸溶液中对304不锈钢的缓蚀性能。结果表明, 三种缓蚀剂均为阴极型缓蚀剂, 对不锈钢具有较好的缓蚀作用;在0.02 mol/L的浓度下, 随着组装时间的延长, 自组装膜对不锈钢的缓蚀效率也相应增强。它们的缓蚀能力与理论EHOMO越高、能量间隙ΔE越低。自组装分子成键能力越强、缓蚀效率越高相一致。三种缓蚀剂分子中的氮原子、氧原子可以与铁原子形成化学键, 发生化学吸附。缓蚀能力依次为: 焦谷氨酸>焦谷氨酰胺>谷氨酸。

The corrosion inhibition performance of L-glutamic, L-Pyroglutamamide and L-Pyroglutamic self-assembled films for 304 stainless steel in 0.5 mol/L H2SO4 solution was investigated by electrochemical impedance spectroscopy, polarization curves, quantum chemical calculations and molecular dynamics. The results of electrochemical method showed that three kinds of inhibitors performed pretty inhibiting efficiency for 304 stainless steel in 0.5 mol/L H2SO4 solution. And at the same concentration of inhibitors, the longer the assembled time, the better the effect of inhibition. According to the results of polarization curves, all these inhibitors were cathodic inhibitors. The results of quantum chemical calculations were the same as those of electrochemical method, and the inhibition efficiency of the three inhibitors was related the values of EHOMO and ΔE. The inhibition performance of the compound was assumed to occur by adsorption on the 304 SS surface through the active centers in the molecule. The results indicated that the corrosion inhibition was due to the formation of a chemisorbed film on the steel surface. The inhibition efficiency of the three inhibitors decreased as follows: L-Pyroglutamic>L-Pyroglutamamide>L-glutamic.