Abstract
Abstract This study investigated the feasibility of using atmospheric pressure plasma enhanced chemical vapor deposition (APPECVD) system using tetraethoxysilane (TEOS)/O 2 plasma to deposit SiO x films as anti-corrosion layer on the AZ31 magnesium alloys. SiO x films were characterized by a scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier-transform infrared spectroscopy (FTIR) to study the surface morphology, and composition. In addition, the corrosion protection afforded by such thin films was investigated by electrochemical techniques, and relationships among composition, structure, and electrochemical properties of these films are reported. The results showed that deposition of silica-like dense film at an O 2 carrier gas flow rate of 1800 sccm represented a near stoichiometric composition of O/Si ratio (2.0) and a lower degree of porosity, while silicone-like film with an O/Si ratio of 3.7 and higher degree of porosity was obtained at 600 sccm. The potentiodynamic polarization tests show that both SiO x films coated on AZ31 alloys have more positive corrosion potential and lower corrosion current density than AZ31 substrates, indicating the corrosion resistance of AZ31 can be improved by depositing SiO x film on its surface. In particular, as the surface is more compact and cross-linked, the silica-like film has a better corrosion resistance than the silicone-like film.
Published Version
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