EVALUATION OF CORROSION PROTECTION CAPACITY OF DOPED PPY FILM FOR STAINLESS STEEL IN AN ACIDIC MEDIUM

Advanced corrosion protection methods include covering stainless steel surfaces with conductive polymer-based coatings. Polypyrrole and polypyrrole composites of tungstate of different concentrations were deposited on stainless steel-304 using cyclic voltammetry and their elemental analysis was verified by EDX analysis. EIS and potentiodynamic polarization analysis show that the corrosion protection efficiency (CPE) of polypyrrole composites is higher than polypyrrole coating. The reduction in corrosion rate due to the inhibitory action of tungstate through the physical barrier and anodic protection mechanism was validated by greater Rct and lower Icorr values of polypyrrole composites. In the composites, with increasing the concentration of tungstate in polypyrrole from 5% to 15%, CPE also increases, as polypyrrole composites are more able to shift the corrosion potential of stainless steels towards the passive zone and form a new nonporous passive oxide film on the surface. With a 15% concentration coating, the highest CPE of 93% and the lowest corrosion rate of 130 mmpy were obtained, indicating that the entire stainless steel active surface area is completely absorbed and that no active sites exit for adsorption at this concentration. The synthesized polypyrrole composites with a 15% concentration offer excellent corrosion protection prospects.