ENVIRONMENTALLY FRIENDLY CONVERSION FILMS ON Zn AND TERNARY ZINC BASED ALLOYS – OBTAINING AND PROTECTIVE PROPERTIES
The objects of this study are galvanically deposited Zn and Zn-Ni-P coatings additionally treated (passivated) in environmentally friendly Cr(III)-based composition for obtaining of conversion films (CF). The aim of this treatment is to improve the corrosion-resistant properties of the coatings.
The elemental composition and surface morphology of the newly obtained systems “galvanic coating/conversion film” are investigated with EDS and SEM analyses.
Protective properties of the conversion films are defined with potentiodynamic polarization curves and polarization resistance measurements in a model medium containing chloride ions (5% NaCl) which leads to appearance of local corrosion.