Research Progress on Electrochemical and Photo-electrochemical Properties of Passive Film on Metal Surface

Electrochemical and photo-electrochemical techniques are effective means of metal corrosion and inhibition behavior research. This paper summarizes the research progress on electrochemical and photo-electrochemical characteristics of passive film on metal surface, mainly related to the steady-state optical properties, transient calculation of optical parameters, measurement of space charge of passive film and photoconductivity and so on. Photo-electrochemical research is used to obtain the electrical properties of passive film, such as the band gap, conductivity type and flat band, to judge the passive film structure, and to calculate the direct or indirect band gap by drawing (Iph·hν)n-hν curve and measuring the space charge and the relationship between the photocurrent or incident light energy (wavelength) and the applied potential. Also, this paper analyzes the progress in the measurement and calculation of transient optical properties such as the quantum life and migration constant; the transient space capacitance and transient photoconductivity at home and abroad.