氯化硝基四氮唑蓝对钢在盐酸溶液中的缓蚀作用

采用失重法、动电位极化曲线、电化学阻抗谱(EIS)和扫描电子显微镜(SEM)研究了氯化硝基四氮唑蓝(NTBC)在1.0-5.0mo·lL-1HCl溶液中对冷轧钢(CRS)的缓蚀作用.结果表明:NTBC在1.0mo·lL-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,但随盐酸浓度和温度的增加而减小.求出了相应的吸附热力学(吸附自由能ΔG0,吸附焓ΔH0,吸附熵ΔS0)和腐蚀动力学参数(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:NTBC为混合抑制型缓蚀剂;EIS谱在高频区呈容抗弧,在低频区出现感抗弧,电荷转移电阻随缓蚀剂浓度的增加而增大.SEM再次表明NTBC对钢在盐酸介质中的腐蚀产生了明显的抑制作用.

Inhibition Effect of Nitrotetrazolium Blue Chloride on the Corrosion of Steel in Hydrochloric Acid Solution

The inhibition effect of nitrotetrazolium blue chloride (NTBC) on the corrosion of cold rolled polarization curves, electrochemical impedance spectroscopy (EIS), and scanning electron microscopy adsorption of NTBC on the CRS surface obeys the Langmuir adsorption isotherm. Inhibition efficiency increases with inhibitor concentration while it decreases with hydrochloric acid concentration and temperature. The adsorption thermodynamic parameters (adsorption free energy ΔG0, adsorption enthalpy ΔH0, adsorption entropy ΔS0) and corrosion kinetic parameters (corrosion rate constant k, kinetic reaction constant B) were also calculated. Based on these parameters the inhibitive mechanism is discussed.Potentiodynamic polarization curves show that NTBC acts a mixed-type inhibitor. EIS spectra exhibit one capacitive loop at high frequency and this is followed by a small inductive loop at low frequency, and the charge transfer resistance increases with inhibitor concentrations. SEM clearly shows that the addition of NTBC can drastically retard the corrosion of steel in hydrochloric acid media.