New bi-Pyrazol-Carbohydrazides, N,N-bis (3-Carbohydrazide-5-methylpyrazol-1-yl) methylene (M2PyAz) and 1,4-bis (3-Carbohydrazide-5-methylpyrazol-1-yl) butane (B2PyAz), were synthesized and their inhibitor effect against mild steel (MS) corrosion in 1 M HCl solution has been evaluated. Comparative study of inhibitory action of M2PyAz and B2PyAz was conducted first using weight loss measurements (WL), potentiodynamic polarization (PDP), electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM) and theoretical computational methods. The inhibition efficiencies of M2PyAz and B2PyAz can reach 98.6% and 87.8% respectively when the optimal concentration is 10–3 M. This result indicates that M2PyAz behave as excellent corrosion inhibitor towards MS because of its molecular size giving a denticity of electron donor atoms. EIS results indicate that the charge transfer resistance increases with augmentation concentration for both inhibitors and the MS corrosion in this system is controlled by a charge transfer process. PDP curves suggest that the M2PyAz and B2PyAz act as mixed type corrosion inhibitors. Free energy of adsorption obtained from the Langmuir isotherm model for both M2PyAz and B2PyAz implies that both molecules inhibit the acid attack mainly by chemisorption. WL-measurements were carried out in temperature range of 308–348 K, illustrating approximately 98.5% and 89% inhibitory efficiency respectively for M2PyAz and B2PyAz after 6 h immersion at 308 K in 1 M HCl solution. SEM images indicates the protective layer growth on the surface of metal in the presence of both inhibitors. SEM images analysis in the presence of both inhibitors confirmed the electrochemical outcomes. Density functional theory (DFT) method and molecular dynamics simulations (MDs) application suggest that M2PyAz and B2PyAz can show excellent corrosion inhibition character. The trend of reactivity of both molecules M2PyAz and B2PyAz is in agreement with experimental study.

新的双-吡唑-碳酰肼，N,N-双（3-碳酰肼-5-甲基吡唑-1-基）亚甲基（M2PyAz）和1,4-双（3-碳酰肼-5-甲基吡唑-1-基）丁烷（合成了B2PyAz )，并评估了它们在 1 M HCl 溶液中对低碳钢 (MS) 腐蚀的抑制剂效果。M2PyAz和B2PyAz的抑制作用的比较研究首先使用重量损失测量 (WL)、动电位极化 (PDP)、电化学阻抗谱 (EIS)、扫描电子显微镜 (SEM) 和理论计算方法进行。M2PyAz和B2PyAz的抑制效率当最佳浓度为 10-3 M 时，可分别达到 98.6% 和 87.8%。该结果表明M2PyAz对 MS 表现出优异的腐蚀抑制剂，因为它的分子大小提供了电子供体原子的同一性。EIS 结果表明电荷转移电阻随着两种抑制剂浓度的增加而增加，并且该系统中的 MS 腐蚀受电荷转移过程控制。PDP 曲线表明M2PyAz和B2PyAz作为混合型腐蚀抑制剂。从M2PyAz和B2PyAz的 Langmuir 等温线模型获得的吸附自由能这意味着两种分子主要通过化学吸附来抑制酸侵蚀。WL 测量在 308-348 K 的温度范围内进行，表明M2PyAz 和 B2PyAz在 1 M HCl 溶液中以 308 K 浸泡 6 小时后分别具有约 98.5% 和 89% 的抑制效率。SEM 图像表明在两种抑制剂存在下金属表面上的保护层生长。在两种抑制剂存在下的 SEM 图像分析证实了电化学结果。密度泛函理论 (DFT) 方法和分子动力学模拟 ( MDs ) 应用表明M2PyAz 和 B2PyAz可以显示出优异的缓蚀特性。M2PyAz 和 B2PyAz两种分子的反应性趋势 与实验研究一致。