Depassivation―repassivation behavior of a pure iron surface investigated by micro-indentation
Depassivation―repassivation behavior of a pure iron surface investigated by micro-indentation
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DOI：
10.1016/j.electacta.2009.09.063
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发表时间：
2010
影响因子：
6.6
通讯作者：
Takatoshi Yamamoto;K. Fushimi;H. Habazaki;H. Konno
中科院分区：
文献类型：
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作者：
Takatoshi Yamamoto;K. Fushimi;H. Habazaki;H. Konno
在恒电位控制下，用微压痕法研究了纯铁表面在硼酸盐缓冲溶液中的去钝化-再钝化行为。在压头向下和向上驱动过程中，由于基体的塑性变形而不是弹性变形和再钝化引起的去钝化，都会出现电流峰值。电流峰值的总电荷与最大负载成比例。总电荷也随着压痕间歇时间的增加而增加，表明即使在应力松弛期间，钝化膜也会破裂。从电荷平衡估计，82%和18%的膜破裂分别发生在向下驱动和间歇期间，并且在向上驱动期间没有破裂发生。此外，膜破裂面积估计为塑性变形表面积的80%。钝化膜的部分保留表明钝化膜的延展性高于基体。
Depassivation–repassivation behavior on a pure iron surface in borate buffer solution was examined under potentiostatic control by a micro-indentation test. Current peaks emerge during both downward and upward drives of the indenter due to depassivation which is caused by plastic deformation of the substrate but not elastic deformation and repassivation. The total electric charge of the current peaks is proportional to the maximum load. The total electric charge also increases with increase in intermission time of the indentation, indicating that the passive film is ruptured even during stress relaxation. It is estimated from the electric charge balance that 82% and 18% of the film rupture occurs during the downward drive and intermission, respectively, and that no rupture occurs during the upward drive. Furthermore, the film-ruptured area is estimated to be 80% of the plastic deformed surface area. The partial retainment of the passive film on iron suggests that the ductility of the passive film is higher than that of the substrate.