MMI作为铜的盐酸酸洗缓蚀剂作用机理的研究

用失重法研究了N-甲基-2-巯基咪唑（MMI）在5％盐酸中对铜的酸洗缓蚀性能.探讨了温度和MMI浓度对缓蚀效果的影响，从中得出了MMI在铜表面的吸附等温式，计算了吸附热及MMI的加入对铜在盐酸中腐蚀反应活化能的影响，进而探讨了MMI对铜缓蚀作用的机理.结果表明， 30 ℃下，在5％盐酸中，当MMI的浓度在3 mmol?L－1和8 mmol?L－1之间时,缓蚀率随MMI浓度的增加而迅速增加，当浓度达到8 mmol?L－1时，缓蚀率趋于定值，而当浓度小于3 mmol?L－1时， MMI的加入会加速铜的腐蚀；吸附在铜表面的MMI分子间的作用力整体表现为引力； MMI在铜表面的吸附是吸热反应； MMI的加入降低了铜的腐蚀反应活化能.

The Action Mechanism of MMI as Corrosion Inhibitor of Copper for Hydrochloric Acid Pickling

The corrosion inhibition property of 2-mercapto-N-methy-imidazole(MMI) for copper in 5% HCl was studied using weight loss method. The influences of temperature and the concentration of MMI on the corrosion inhibition efficiency were determined, from which the adsorption isotherm was obtained. The heat of adsorption and the effect of the addition of MMI on the activation energy of the corrosion were calculated. The corrosion inhibition mechanism of MMI for copper was proposed. The results indicated that the corrosion inhibition efficiency of MMI for copper increased very sharply with the rise of the concentration of MMI when the concentration was between 3 mmol@ L- 1 and 8 mmol@ L- 1 and was approximately constant when the concentration was higher than 8 mmol@ L- 1, while the addition of MMI accelerated the corrosion of copper if the concentration is lower than 3 mmol@ L- 1. The interaction force between the adsorbed MMI molecules displayed attractive one on the whole when the concentration was in the range of 4.5 mmol@ L- 1 to 8 mmol@ L- 1. The adsorption of MMI on copper surface was a heat absorbing reaction, and the addition of MMI reduced the activation energy of the corrosion of copper.