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采用极化曲线、电容-电位曲线、Mott-Schottky分析以及电化学阻抗(EIS)等电化学方法研究了镁合金在含F-NaOH溶液中的阳极钝化行为.结果表明,在-1.2～1.8V的电位范围内,镁合金在含F-的NaOH溶液中发生阳极钝化.所形成的钝化膜表现出n型半导体的导电特性.在0.7～1.8V的电位范围内,随着F-浓度增大,镁合金的阳极极化电流密度呈现出随着电位升高而逐渐增大的趋势,随着F-浓度增大这一趋势逐渐减弱.并且F-浓度的增大使得镁合金表面空间电荷层电容和钝化膜的载流子密度都不断减小.通过极化曲线和电化学阻抗共同说明,在5%的Na2SO4溶液中,NaOH溶液中阳极钝化后的镁合金随着钝化体系中F-浓度的增加其耐蚀性逐渐减弱。
The anodic passivation behavior of magnesium alloy in F-NaOH solution was investigated by means of polarization curves, capacitance-potential curves, Mott-Schottky analysis and electrochemical impedance spectroscopy (EIS) V within the potential range, the magnesium alloy in the F-containing NaOH anode passivation occurred.The resulting passivation film showed the conductivity of n-type semiconductor in the potential range of 0.7 ~ 1.8V, with the F- With the increase of concentration, the anodic polarization current density of magnesium alloy shows a trend of increasing with the increase of potential, and the trend of decreasing gradually with the increase of F- concentration.And the increase of F- concentration makes the surface of magnesium alloy Space charge layer capacitance and passivation film carrier density are decreasing.Polarization curves and electrochemical impedance together illustrate that in 5% Na2SO4 solution, NaOH solution anodized magnesium alloy with blunt The F-concentration in the system increases its corrosion resistance gradually weakened.