Plasma-polymerized coatings using HMDSO precursor for iron protection

A large microwave plasma reactor was used for the deposition of plasma-poly merized coating from hexamethyldisiloxane (HMDSO)/oxygen(O-2) mixtures on i ron samples. The plasma was characterized by optical emission spectroscopy as a function of the HMDSO to oxygen ratio. Infrared spectroscopy was used to investigate the coating structure, The variation of the HMDSO content in the feed provides a large wide of coatings, from. silica (HMDSO content: 2 0%) to polymer (HMDSO content >80%). Electrochemical impedance spectroscopy was used to predict corrosion protective properties of the coating. Differ ent HMDSO/O-2 ratios in the mixture provide varying degree of corrosion pro tection and the best protection was obtained for the plasma-polymerized coa ting from HMDSO 80% content precursor. (C) 2000 Elsevier Science S.A. All r ights reserved.