Effect of doping by corrosion inhibitors on the morphological properties and the performance against corrosion of polypyrrole electrodeposited on AA6061-T6

This paper describes the electrosynthesis of polypyrrole (PPy) onto AA6061-T6 aluminum alloy from a sulfuric acid solution doped with molybdate anions (MoO42−) or 8-hydroxyquinoline (8HQ) species. These dopant compounds were chosen as they have been proven to be effective in mitigating the corrosion in chloride medium. The protectiveness of PPy coatings incorporating these corrosion inhibitors within the polymer matrix is discussed. The coatings were morphologically characterized via scanning electron microscopy (SEM) and evaluated electrochemically via polarization in 0.5 M NaCl. The results show that doping PPy with molybdates or 8HQ changes its morphological properties and its effectiveness in preventing passivity loss for AA6061-T6 in chloride media.

► Polypyrroles are electrochemically deposited onto AA6061-T6. ► Polymers are doped or not with molybdate anions (MoO42−) or 8-hydroxyquinoline (8HQ). ► Doping PPy changes its morphological properties and its effectiveness in preventing passivity loss for AA6061-T6 in chloride media.