Study on corrosion protection properties of PANI/ZnO/Zn/Graphene coating on aluminum alloy

A PANI/ZnO/Zn/Graphene composite anti-corrosion coating was uniformly brushed on the surface of 2A12 aluminum alloy. The anti-corrosion performance of the coating in 3.5 % NaCl solution was studied. The potentiodynamic polarization of the 2A12 aluminum alloy coated with the PANI/ZnO/Zn/Graphene composite revealed that the anti-corrosion performance was greatly improved by prolonging the tortuosity of diffusion pathways for corrosive reactants through graphene, when compared to those with PANI/ZnO/Zn coating and 2A12 aluminum alloy. The 3.5 % NaCl solution immersion testing of PANI/ZnO/Zn/Graphene coating showed that the anti-corrosion performance of the coating was weakened by the solute immersion in the early stage of the experiment, while the pores and defects of the coating were gradually filled with corrosion products after immersion for 480 h, resulting in further improvement of corrosion resistance. The EIS results showed that the total impedance of PANI/ZnO/Zn/Graphene coating is greater than PANI/ZnO/Zn coating, and the impedance module value can reach 1.98 × 105 Ωcm2. In general, it is concluded that PANI/ZnO/Zn/Graphene coating have high protective properties.