铀在三种溶液中的动电位极化和电化学阻抗谱研究

POTENTIODYNAMIC POLARIZATION AND EIS BEHAVIOR OF URANIUM IN THREE DIFFERENT SOLUTIONS

用动电位极化和电化学阻抗谱(EIS)研究铀在0.5 mol/LH2SO4溶液、1 mol/L NaOH溶液和1 mol/L Na2SO4溶液中的腐蚀电化学行为。结果显示,铀在H2SO4溶液和Na2SO4溶液中的动电位极化曲线有类似的极化趋势,而在NaOH溶液中则有明显的钝化现象。EIS谱均有明显的容抗弧特征。利用软件对电化学阻抗谱进行拟合,得到了3种溶液中铀的电化学阻抗谱等效电路,拟合的阻抗谱与实验测得的阻抗谱拟合得比较好,拟合方差在10-3数量级。

The corrosion electrochemical behavior of cast uranium has been studied in 0.5 mol/L H2SO4, 1 mol/L NaOH and 1 mol/L Na2SO4 solutions respectively using potentiodynamic polarization and electrochemical impedance spectroscopy （EIS） techniques. The results from potentiodynamic polarization testing displayed similar tendency in H2SO4 and Na2SO4 solutions, while in NaOH solution it exhibited an obvious ＂passivity＂ region between passivation potential Ep （-0.070 V） and activation potential EF （0.081 V）. The EIS results all showed distinct capacitance-resistance arc characteristic. The software named ZsimpWin was used to fit the data from EIS to obtain corresponding equivalent circuit which consistent well with the measured data.The chi-square values between simulated data and measured data are within 10^-3 order of magnitude.