Inhibiting and healing effects of potassium permanganate for silane films

•Healing sol–gel film was obtained by adding KMnO4 into electrolyte.•An optimal inhibitor mole ratio of MnO4−/Cl− for Si sol–gel was 2 × 10− 1.•The best protective efficiency was approximately 99.24%.•The inhibiting effect may be due to production of insoluble manganese hydroxide/oxide.

In this study, the inhibiting and healing effects of potassium permanganate for silane films were investigated, and the optimal mole ratio of MnO4−/Cl− was also obtained. The inhibiting process and healing mechanism were studied by electrochemical measurements and scanning electron microcopy coupled with energy dispersive spectroscopy. Results demonstrated that the introduction of potassium permanganate to electrolyte could stop the development of corrosion process and the optimal inhibiting mole ratio of MnO4−/Cl− is 2 × 10− 1 with a protective efficiency about 99.24%. According to its high protective efficiency and the nice results of long-term immersion test, potassium permanganate as an inhibitor could prolong the lifetime of silane films and expand its scope of application.