溴代十六烷基吡啶对冷轧钢在三氯乙酸中的缓蚀性能

Inhibition action of hexadecylpyridinium bromide on cold rolled steel in Cl3CCOOH solution

采用失重法、动电位极化曲线、电化学阻抗谱(EIS)及扫描电子显微镜(SEM)研究了阳离子表面活性剂溴代十六烷基吡啶(HDPB)在0.10 mol·L^(-1)ClCCOOH溶液中对冷轧钢(CRS)的缓蚀性能。结果表明:20℃时100 mg·L^(-1)HDPB的最大缓蚀率可达93.7%,HDPB浓度越高,缓蚀性能越强,而温度越高,缓蚀性能越弱。HDPB在CRS表面的吸附过程包含了物理吸附和化学吸附,符合Langmuir吸附等温式,且为放热吸附。冷轧钢在添加HDPB的ClCCOOH溶液中腐蚀速率随温度的变化规律符合Arrhenius和过渡态理论方程,添加HDPB后表观活化能、指前因子、表观活化焓、表观活化熵均增大。HDPB为混合型缓蚀剂,其电化学作用机理为“几何覆盖效应”,加入HDPB后,Nyquist图主要由高频区的容抗弧组成,且随着HDPB浓度增大,电荷转移电阻增大,SEM微观形貌进一步证实了HDPB有效减缓了CRS表面的腐蚀速度。

The inhibition action of the cationic surfactant of hexadecylpyridinium bromide(HDPB)on cold rolled steel(CRS)in 0.10 mol·L^(-1)ClCCOOH solution was studied by weight loss method,potentiodynamic polarization curves,electrochemical impedance spectroscopy(EIS)and scanning electron microscope(SEM).The results show that the maximum inhibition efficiency of 100 mg·L^(-1)HDPB at 20℃is as high as 93.7%in 0.10 mol·L^(-1)ClCCOOH solution.The inhibitive performance increases with the increase of the concentration of HDPB,while decreases with the increase of experimental temperature.The adsorption of HDPB on CRS surface involves both physical adsorption and chemical adsorption,which conforms to Langmuir adsorption isotherm,and is exothermic.The corrosion rate of CRS dependence with temperature follows Arrhenius and transition state equations,and the kinetic corrosion parameters of apparent activation energy,pre-exponential factor,apparent activation enthalpy and apparent activation entropy are increased with the addition of HDPB.Polarization curves show that HDPB is a mixed-type inhibitor,and the electrochemical mechanism of HDPB on CRS surface is"geometric blocking effect".Nyquist plots are mainly composed of capacitive reactance arcs in the high frequency region after adding HDPB,and the charge transfer resistance increases with the increase of HDPB concentration.SEM micrographs confirm that the corrosion degree of CRS surface is slowed with the addition of HDPB.