Self-healing protective films prepared on zinc by treatments with cerium (Ⅲ) nitrate and sodium phosphate

摘要

Chromate-free, self-healing protective films were prepared on a surface of zinc electrode previously treated in a solution of cerium (Ⅲ) nitrate Ce(NO_3)_3 by coverage of the surface with a layer of sodium phosphate Na_3PO_4. The self-healing ability of the film was examined by polarization measurements of the electrode after scratching the surface with a knife-edge crosswise and immersed in an aerated 0.5 M NaCl solution for many hours and by observation of pit formation at the scratches.