Effects of Concentration of Surfactant FC4 on Surface Morphology and Corrosion Resistance of Ni-P-PTFE Composite Coatings

Ni-P-PTFE composite coatings were prepared by electroless composite plating on the surface of 30CrMnSi alloy steel in the plating solution with 0.12-0.24 g·L-1 surfactant FC4. Effects of concentration of surfactant FC4 on surface appearance and corrosion resistance of the coatings were studied. The results show that, with the increase of concentration of FC4, the surface appearance of the coatings became worse, deposition rate decreased, porosity increased and corrosion resistance decreased. The main reason was that excessive FC4 would be absorbed strongly on the surface of substrate, occupied the active centers, and then hindered the deposition process. The coating owned the best corrosion resistance when the concentration of FC4 was 0.12 g·L-1.