Abstract

Pyrazinecarboxamide was examined against mild steel corrosion in 0.5 M HCl solution. The electrochemical techniques like electrochemical impedance spectroscopy, linear polarization resistance and potentiodynamic polarization measurements were carried out in the presence of various concentrations of pyrazinecarboxamide ranging from 0.25 mM to 1.0 mM. The inhibition effect of pyrazinecarboxamide on the mild steel surface was studied by atomic force microscopy and scanning electron microscopy. The adsorption of this inhibitor was determined to fit Langmuir adsorption isotherm. The adsorption/desorption equilibrium constant was calculated as 2.985 × 10⁴ M⁻¹, indicating that high proportion of pyrazinecarboxamide takes place on mild steel surface. The inhibition efficiency was found as 93.5% from electrochemical impedance spectroscopy measurement in an acid solution containing 1.0 mM pyrazinecarboxamide. Quantum chemical parameters that were in good agreement with experimental results were determined by density functional theory.

摘要

在 0.5 M HCl 溶液中检查吡嗪甲酰胺对低碳钢的腐蚀。在 0.25 mM 至 1.0 mM 的各种浓度的吡嗪甲酰胺存在下，进行了电化学阻抗谱、线性极化电阻和动电位极化测量等电化学技术。采用原子力显微镜和扫描电子显微镜研究了吡嗪甲酰胺对低碳钢表面的缓蚀作用。确定该抑制剂的吸附符合 Langmuir 吸附等温线。吸附/脱附平衡常数计算为2.985×10 ⁴  M ^-1，表明在低碳钢表面发生了高比例的吡嗪甲酰胺。在含有 1.0 mM 吡嗪甲酰胺的酸溶液中，通过电化学阻抗谱测量发现抑制效率为 93.5%。与实验结果非常吻合的量子化学参数由密度泛函理论确定。