Hydrophobicity and corrosion resistance of steels coated with PFDS film

A simple evaporation method was applied to deposit films of hydrophobic organic compounds, either polyethylene (PE) or 1H,1H,2H,2H-perfluorodecyltriethoxysilane (PFDS), on various steel surfaces. The endurance of these films was evaluated after ultrasonic cleaning, ultraviolet (UV) light irradiation and heat treatment, and the corrosion behaviour of the PFDS coated steels was measured in NaCl solutions. The results show that in order to achieve high hydrophobicity on steel, the most suitable deposition conditions are exposure to saturated PE or PFDS vapours for a time of 1·8 ks at 393 K, in the case of PE, and 423 K, in the case of PFDS. The hydrophobicity of the PFDS coated surfaces was significantly more stable than that of the PE coated surfaces under ultrasonic cavitation, UV light irradiation and heating to 373 K. The deposition of a PFDS film on the surfaces of SUS304, SUS316 and SS400 steels improved their corrosion resistance in NaCl solution.