The Effect of 304 Stainless Steel Substrate Surface Preparation Method on Coating Process of Polypyrrole/Polyaniline Conductive Polymers and Corrosion Resistance Improvement

In this study, the effect of substrate surface preparation on the polypyrrole/polyaniline conductive polymers coating process and corrosion resistance in the presence of coating has been investigated. The preparation of the 304 stainless steel substarate was done by electropolishing, manual grinding, and sandblasting. Atomic force microscopy (AFM), scanning electron microscopy (SEM), and roughness tester have been used to investigate the surface morphology. The coating process for polypyrrole/polyaniline conductive polymers were carried out over a period of 900 seconds with potentiostat technique at a voltage of +900 mV. Based on pull-off test results, the most adherent coating belonged to manual grinded sample with 0.67 MPa tensile stress. According to the results of electrochemical impedance test and polarization of potentiodynamics after one hour immersion in a solution of 3.5 wt % sodium chloride, the substrate prepared by manual grinding had the highest polarization resistance of 18428 Ω.cm2, the least corrosion current density of 1.76 × 10-7 A/cm2, and the highest potential of -0.080 V vs. SCE.