目的 研究 4-苯基氨基硫脲（4-PTC）对 Q235 钢在 1mol/L HCl 中的缓蚀作用。 方法 采用异硫氰酸苯酯和水合肼为原料，合成 4-PTC。采用熔点分析、核磁共振氢谱和红外光谱等方法确定合成物质为目标产物 4-苯基氨基硫脲。采用静态失重法、电化学极化曲线法、电化学阻抗谱法和扫描电子显微镜法，分析研究 4-PTC 的缓蚀性能。 结果 静态失重实验表明，当 4-PTC 浓度增加到 1.0 mmol/L时，缓蚀效率达到 85.9%，在 Q235 钢表面吸附符合 Langmuir 吸附等温式，形成单分子吸附层。计算得到吉布斯自由能为?35.60 kJ/mol，说明缓蚀剂分子在 Q235 钢表面吸附同时存在物理吸附和化学吸附过程。动电位极化曲线表明，该缓蚀剂是以阴极型为主的混合型缓蚀剂，当4-PTC浓度增加到1.0 mmol/L时，缓蚀效率达到 83.6%。电化学阻抗谱表明，随 4-PTC 浓度的增加，电荷转移电阻值增大，双电层电容值减小，金属腐蚀速率降低，缓蚀作用增强。当 4-PTC 浓度增加到 1.0 mmol/L 时，缓蚀效率达到84.7%。扫描电子显微镜表明，缓蚀剂分子能有效保护金属表面，抑制腐蚀。 结论 在盐酸介质中， 4-PTC对 Q235 钢具有优良的缓蚀性能。

Objective To investigate the inhibition performance of 4-Phenylthiosemicarbazide (4-PTC) for Q235 steel in 1 mol/L HCl solution. Methods A new corrosion inhibitor, 4-PTC, was synthesized using phenyl isothiocyanate and hydrazine hydrate as raw materials. The synthesized compound was confirmed by melting point, 1H-NMR and IR methods. The corrosion inhibition efficiency of 4-PTC was measured by weight loss, potentiodynamic polarization, electrochemical impedance spectroscopy and scanning electron microscope methods. Results The results of weight loss measurements showed that the inhibition efficiency of 4-PTC could reach up to 85.9% at the concentration of 1.0 mmol/L and the adsorption process obeyed the Langmuir adsorption isotherm, forming monolayer. The value of ΔGads was -35.60 kJ/mol, which indicated that the adsorption mechanism involved both chemisorption and physisorption. The potentiodynamic polarization plots showed that 4-PTC acted as a mixed type inhibitor and showed more pronounced influence in the cathodic polarization plots compared to that in the anodic plots. The inhibition efficiency of 4-PTC could reach up to 83.6% at the concentration of 1.0 mmol/L. Meanwhile, the electrochemical impedance showed that the charge transfer resistance increased with the increase of the 4-PTC concentration, while the value of double layer capacitance decreased. This phenomenon showed that the corrosion rate decreased and the inhibition efficiency increased. The inhibition efficiency of 4-PTC could reach up to 84.7% at the concentration of 1.0 mmol/L. The scanning electron microscope method showed that the 4-PTC had excellent inhibition behavior and could protect the Q235 steel. Conclusion 4-PTC showed good inhibition efficiency for Q235 steel in HCl solution.