Evaluation of corrosion resistance of steel coated with zinc-iron alloy electrodeposits containing BTSE, BTESPTS and rare earth salts as conversion films

This study aims to evaluate the corrosion resistance of steel coated with ZnFe alloy electrodeposits treated with films consisted of a pre-layer obtained through immersion in a rare earth salt solution using Ce or La elements plus a silane thin film of BTSE (bis 1, 2 - [triethoxysilyl]) ethane) and / or BTESPTS (bis-(3 - [triethoxysilyl]-propyl) - tetrassulfeto). These systems were evaluated by polarization curves, electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The polarization and EIS results indicated that the studied systems were effective against corrosion and that their performance depends on the type of cation salt. The ZnFe + Ce + + BTSE BTESPTS system proved to be the best result against corrosion.