Abstract The inhibitory effect of 1,5-dimethyl-1H-pyrazole-3-carbohydrazide (PyHz) on the corrosion of mild steel in 1 M HCl medium has been examined and characterized using electrochemical impedance spectroscopy (EIS), polarization curves plot (PDP), gravimetrical and SEM/EDX methods. The obtained results indicate that PyHz has a good inhibitory and its inhibition efficiency reaches 96% at 10−3 M. Weight loss and electrochemical techniques results were in reasonable agreement. The inhibitory effect increased with the concentration rise of PyHz but decreased with the increase in temperature. PDP technique suggested that the PyHz acted as a mixed type inhibitor. The adsorption process obeyed the Langmuir isotherm model. Thermodynamic parameters and the scanning electron microscopy analysis were discussed for mild steel in 1 M HCl medium and revealed the adsorption mechanism of PyHz. An electrical equivalent circuit was utilized to analyze EIS data in order to give an adequate model for adsorption process. Surface topography analysis strongly confirmed the electrochemical findings. The adsorption behavior of PyHz on steel surface was also inspected using Density Functional Theory (DFT) method and simulations of Monte Carlo. Quantum chemical calculations and Monte Carlo simulations have confirmed the experimental findings.

中文翻译：

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吡唑碳酰肼作为 HCl 介质中低碳钢的缓蚀剂：实验和理论研究

摘要 1,5-二甲基-1H-吡唑-3-碳酰肼 (PyHz) 在 1 M HCl 介质中对低碳钢腐蚀的抑制作用已通过电化学阻抗谱 (EIS)、极化曲线图 (PDP) 进行了研究和表征。 )、重量法和 SEM/EDX 方法。所得结果表明，PyHz 具有良好的抑制作用，其抑制效率在 10-3 M 时达到 96%。失重和电化学技术结果具有合理的一致性。抑制作用随着PyHz浓度的升高而增强，随着温度的升高而减弱。PDP 技术表明 PyHz 作为混合型抑制剂。吸附过程服从朗缪尔等温线模型。讨论了低碳钢在 1 M HCl 介质中的热力学参数和扫描电子显微镜分析，揭示了 PyHz 的吸附机制。使用等效电路来分析 EIS 数据，以便为吸附过程提供适当的模型。表面形貌分析有力地证实了电化学结果。还使用密度泛函理论 (DFT) 方法和蒙特卡罗模拟检查了 PyHz 在钢表面上的吸附行为。量子化学计算和蒙特卡罗模拟证实了实验结果。还使用密度泛函理论 (DFT) 方法和蒙特卡罗模拟检查了 PyHz 在钢表面上的吸附行为。量子化学计算和蒙特卡罗模拟证实了实验结果。还使用密度泛函理论 (DFT) 方法和蒙特卡罗模拟检查了 PyHz 在钢表面上的吸附行为。量子化学计算和蒙特卡罗模拟证实了实验结果。