材料期刊网

采用动电位极化、电化学阻抗和Mott-Schottky等电化学测试方法，研究了在室温、3.5% NaCl溶液条件下，静水压力对纯镍的钝化膜性能的影响。结果表明：随着静水压力的增加，纯镍的腐蚀速度增大，阴极过程保持不变，阳极过程加速。静水压力对阳极过程的影响:一方面提高纯镍钝化膜的抗腐蚀能力，使钝化膜中的受主密度减小，空间电荷层的厚度增加；另一方面，恶化了纯镍的钝化膜腐蚀抗腐蚀能力，使钝化膜变得不稳定，并且表现出较高的化学溶解速度和空穴扩散系数。静水压力对纯镍钝化膜的恶化作用比提高作用对阳极过程的影响更大，导致纯镍的抗腐蚀能力随着静水压力的提高而减小。

The effect of hydrostatic pressure (from 1 to 8 MPa) on corrosion behavior of pure nickel at ambien temperature in 35% NaCl solution were investigated by means of polarization curve,electrochemical impedance spectroscopy (EIS) and MottSchottky measurement.The experimental results revealed that the hydrostatic pressure exhibited a strong influence on the corrosion process of pure nickel.With the increasing of hydrostatic pressure,the corrosion rate of pure nickel increased,the anodic process was accelerated while cathodic process remained unchanged.Hydrostatic pressure possessed two opposite effects on the anodic process of nickel.On one hand,hydrostatic pressure improved the corrosion resistance of passive film of nickel,such as decreasing the acceptor density and increasing the space thickness of the charged layer.On the other hand,hydrostatic pressure deteriorated the corrosion resistance of passive film of nickel,i.e.the passive film became unstable and showed a higher diffusivity.The deterioration effect had greater influence on the anodic process rather than the improvement effect,which lead to the decreasing of the corrosion resistance with the increasing of hydrostatic pressure.