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采用失重法、动电位极化曲线、电化学阻抗谱(EIS)、量子化学计算研究了两种嘧啶衍生物(2-羟基嘧啶(HP)和2-巯基嘧啶(MP))在1.0 5.0 mol L 1HCl溶液中对冷轧钢(CRS)的缓蚀作用.结果表明:HP和MP在1.0 mol L 1HCl溶液中对冷轧钢具有良好的缓蚀作用,且在钢表面的吸附符合Langmuir吸附等温式.缓蚀率随缓蚀剂浓度的增加而增大,但随盐酸浓度的增加而减小.求出了相应的吸附热力学参数(吸附平衡常数(K),吸附自由能(ΔG0))和腐蚀动力学参数(表观活化能(Ea)、指前因子(A)、腐蚀速率常数(k)、动力学常数(B)),并根据这些参数讨论了缓蚀作用机理.动电位极化曲线表明,MP和HP均为混合抑制型缓蚀剂;EIS谱呈单一容抗弧,电荷转移电阻随缓蚀剂浓度的增加而增大.两种嘧啶化合物的缓蚀率排序为MP>HP.量子化学计算结果表明,MP比HP更具吸附活性,缓蚀性能的理论计算和实验结果相一致.
The effects of two pyrimidine derivatives (2-hydroxypyrimidine (HP) and 2-mercaptopyrimidine (MP)) in the presence of 1.0 5.0 mol L were studied by weight loss method, potentiodynamic polarization curve, electrochemical impedance spectroscopy (EIS) 1HCl solution.The results showed that HP and MP had good corrosion inhibition on cold rolled steel in 1.0 mol L HCl solution and the adsorption on the steel surface accorded with Langmuir adsorption isotherm The corrosion inhibition rate increased with the increase of corrosion inhibitor concentration, but decreased with the increase of hydrochloric acid concentration.The corresponding adsorption thermodynamic parameters (adsorption equilibrium constant (K), adsorption free energy (ΔG0)) and corrosion Kinetic parameters (apparent activation energy (Ea), pre-exponential factor (A), corrosion rate constant (K) and kinetic constant (B)) were calculated and the mechanism of corrosion inhibition was discussed. The results showed that both MP and HP were mixed inhibitor, and the EIS spectrum showed a single capacitive arc, and the charge transfer resistance increased with the increase of inhibitor concentration.The corrosion inhibition ratios of the two pyrimidine compounds were MP> HP. Quantum chemical calculation results show that MP is more active than HP, the theoretical calculation of corrosion inhibition performance is consistent with the experimental results.