铝阳极氧化膜渗透性的电化学阻抗法分析

Study of Permeability of Anodic Aluminum Oxide Film by Electrochemical Impedance Spectroscopy

电化学阻抗谱(EIS)是研究氧化膜渗透性能的有效技术,据此,对磷酸介质中制备的氧化膜在H2O/H2O,0.1mol/LNaCl/H2O,0.1mol/LNaCl/0.1mol/LNaCl体系及0.1mol/LNaCl/H2O体系中不同渗透时间的电化学阻抗谱进行了初步探讨。结果表明:所设计的铝阳极氧化膜渗透的实际体系可以用(RC)R(QR)R(RC)等效电路来表示;交流阻抗技术可以对磷酸介质中多孔氧化膜的渗透性进行定性分析;在NaCl/H2O体系中,多孔氧化膜的Nyquist谱是典型的Warburg阻抗谱,有明显的扩散特征,这种特征与氧化膜的渗透性紧密相关;在Bode谱高频区,随着渗透时间的增加,氧化膜的阻抗值呈减小趋势,但下降幅度有限,扩散渗透量很小。

The electrochemical impedance spectra(EIS)of the porous film prepared from phosphoric acid in H2O-H2O,0.1 mol/L NaCl-H2O,and 0.1 mol/L NaCl ～0.1 mol/L NaCl at various permeation duration were primarily ana-lyzed.Results indicate that the practical systematic circuit of por-ous anodic aluminum oxide(AAO)film in H2 O-H2 O,0.1 mol/L NaCl-H2O,and 0.1 mol/L NaCl-0.1 mol/L NaCl solu-tions can be expressed with equivalent circuit(RC)R(QR)R(RC).It is feasible to qualitatively analyze the permeability of the AAO film in phosphoric acid by means of electrochemical im-pedance spectroscopy.The Nyquist plots of the porous films in NaCl-H2O system appear as typical Warburg impedance spectra and show obvious diffusion feature closely related to the perme-ation of the porous film.In terms of the Bode spectra,the imped-ance value decreased gradually with increasing permeability time but assumed minor change,accompanied by a small diffusion a-mount.