pH值对十二胺在碳钢表面的吸附行为及缓蚀机理的影响

摘要

采用电化学方法和扫描电镜技术,研究了pH值对十二胺在碳钢表面的吸附以及对碳钢CO2腐蚀缓蚀机理的影响.研究结果表明,溶液的pH值对十二胺的吸附和缓蚀机理起决定性作用.十二胺对碳钢的缓蚀作用随溶液pH值的增加而增强.pH值为4.9时,十二胺主要抑制腐蚀的阴极过程.缓蚀剂分子在金属表面上的吸附能比较低,缓蚀剂容易发生脱附,因此不能有效抑制腐蚀反应的进行.pH值为6.9时,缓蚀剂的吸附能较高,能够牢固地吸附在金属表面,形成有效的扩散阻挡层,同时抑制腐蚀的阴、阳极过程,从而有效地抑制腐蚀反应的进行.%The effect of pH value on the adsorption behavior and inhibition mechanism of dodecylamine for carbon dioxide corrosion of carbon steel was investigated by electrochemical methods and scanning electron microscopy (SEM). The results indicated that the pH value of the solution played the crucial role to the adsorption behavior and inhibition mechanism of dodecylamine. The inhibition performance of dodecylamine on carbon steel was dependent on the pH value and the inhibition efficiency increased with the increase of pH value. At pH 4.9, dodecylamine mainly inhibited the cathode process of the corrosion. The adsorption energy of dodecylamine on the metal surface was lower.The adsorption of dodecylamine on the metal surface was not stable and an anode desorption phenomenon could be observed. Hence, dodecylamine did not provide effective inhibition to the corrosion. While at pH 6.9, it had much higher adsorption energy. Dodecylamine adsorbed on the metal surface tightly and formed the effective diffusion barrier which inhibited both the cathode and anode processes effectively.