HCl中稀土盐硫酸高铈对1060铝板的缓蚀性能研究

Corrosion inhibition of rare earth salt of ceric sulfate on 1060 aluminum sheet in HCl solution

采用静态失重法、动电位极化曲线和电化学阻抗谱(EIS)研究了稀土盐硫酸高铈[Ce(SO_(4))2·4H_(2)O]对1.0 mol/L HCl中1060铝板的缓蚀性能,并通过扫描电子显微镜(SEM)、原子力显微镜(AFM)和接触角测试深度表征铝表面的微观形貌特征和亲水/疏水性。结果表明,硫酸高铈能有效抑制1060铝板在1.0 mol/L HCl中的腐蚀,表现出良好的缓蚀性能,20℃时100 mg/L Ce(SO_(4))2·4H_(2)O的缓蚀率高达94.3%。硫酸高铈在铝表面的吸附符合Langmuir吸附等温式,标准吸附Gibbs自由能为-27.5 kJ/mol,吸附过程为物理和化学作用的混合吸附。极化曲线表明,硫酸高铈为阴极抑制型缓蚀剂;EIS有两个时间常数,Nyquist呈容抗弧(高频区)和感抗弧(低频区)组成的近似椭圆形特征。添加硫酸高铈后腐蚀电流密度急剧下降,但极化电阻显著增加。SEM和AFM均表明加入硫酸高铈后的铝表面的腐蚀明显减弱,表面粗糙度降低;但接触角和空白盐酸溶液相比增加约40°。

The corrosion inhibition of rare earth salt of ceric sulfate[Ce(SO_(4))2·4H_(2)O]on 1060 aluminum sheet in 1.0 mol/L HCl solution was studied by weight loss,potentiodynamic polarization curves and electrochemical impedance spectroscopy(EIS)methods.The micro-topography and hydrophilic/hydrophobic property of aluminum surface was characterized in depth by scanning electronic microscope(SEM),atomic force microscope(AFM)and contact angle measurements.The results show that ceric sulfate can effectively retard the corrosion of 1060 aluminum sheet in 1.0 mol/L HCl solution,and results in good inhibitive action.The maximum inhibition efficiency of 100 mg/L Ce(SO_(4))2·4H_(2)O is 94.3%at 20℃.The adsorption of ceric sulfate on aluminum surface obeys Langmuir adsorption isotherm with the standard Gibbs adsorption free energy of-27.5 kJ/mol,and the adsorption mechanism is the complex adsorption containing physisorption as well as chemisorption.Potentiodynamic curves indicate ceric sulfate can be arranged as a cathodic inhibitor.EIS has two time constants.The whole Nyquist appears an approximately oval shape that is composed of a capacitive loop(high frequencies)and an inductive loop(low frequencies).With the addition of ceric sulfate,the corrosion current density is significantly dropped,but the polarization resistance is increased.SEM and AFM proves that the corrosive micro-topography and surface roughness of aluminum surface significantly decreases after adding ceric sulfate to aggressive media.As comparing with blank solution,the contact angel of inhibited surface is increased by 40°.