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按照等的观点,孔蚀再钝化的主要原因是由于孔底电位的负移和孔蚀条件下正向阳极化曲线上钝化区的存在。但按照普遍接受的孔蚀理论,孔内表面处于活化态。孔内欧姆电位降是活化和钝化态在同一电极上同时共存的保证。本文用毛细管参比电极测量了孔蚀过程中孔底电位的变化。进行了电流阶跃、扫描试验。认为,蚀孔再钝化的原因是由于孔蚀的竞争机制。任何抑制活化溶解过程的变化都会导致孔内环境改善,孔底电位升高,孔内欧姆电位降减小和再钝化,只要这一变化足以使钝化过程的速度在竞争中快于活化溶解速度。
According to the equivalent point of view, the main cause of pitting and then passivation is due to the negative shift of hole bottom potential and the existence of the passivation region on the positive anodization curve under pitting conditions. However, according to the generally accepted pitting theory, the inner surface of the pores is in an activated state. The ohmic potential drop in the hole is a guarantee that both the activated and the passivated state coexist on the same electrode at the same time. In this paper, the capillary reference electrode was used to measure the change of pore bottom potential during the pitting process. A current step and scan test was performed. It is believed that the reason for the etch-back passivation is due to the competitive mechanism of pitting corrosion. Any change that inhibits the activation dissolution process results in improved pore environment, increased bottom potential, reduced ohmic potential drop in the pores, and re-passivation, as long as this change is sufficient to allow the passivation process to compete faster than active dissolution speed.