Preparation of self-healing protective films on a zinc electrode treated in a cerium(Ⅲ) nitrate solution and modified with sodium phosphate and cerium(Ⅲ) nitrate

摘要

Self-healing protective films were prepared on a zinc electrode previously treated in a Ce(NO_3)_3 solution by modification with Na_3PO_ 4 and Ce(NO_3)_3. The protective and self-healing abilities of the films were examined by polarization measurements and observation of pit formation after the electrode was scratched with a knife-edge crosswise and immersed in oxygenated 0.5 M NaCl at 30℃ for many hours. Mechanisms of the protective and self-healing activities were discussed using X-ray photoelectron spectroscopy and electron-probe microanalysis. The protective and self-healing abilities of the films prepared on the zinc electrode by treatment in the Ce(NO_3)_3 solution and modification with Na_3PO_4 plus Ca(NO_3)_2, Mg(NO_3)_2, Zn(NO_3)_2 or Ce(NO_3)_3 were summarized.