Mechanical, tribological and anti-corrosive properties of polyaniline/graphene coated Mg-9Li-7Al-1Sn and Mg-9Li-5Al-3Sn-1Zn alloys

Abstract The mechanical, tribological and corrosion protection offered to Mg-9Li-7Al-1Sn and Mg-9Li-5Al-3Sn-1Zn alloys by the epoxy coating containing polyaniline/graphene (PANI/Gr) pigments is undertaken in the current work. PANI/Gr containing coatings were observed to be strongly adherent with a higher scratch hardness ( H s ) and plowing hardness ( H p ), i.e. H s of 0.43 GPa, and H p of 0.61 GPa, respectively when compared to that of neat epoxy coating ( H s of 0.17 GPa, and H p of 0.40 GPa, respectively). Due to their higher H s and H p values, PANI/Gr based coatings displayed an enhanced wear resistance (Wear volume, W v  = 4.53 × 10 -3  m 3 ) than that of neat epoxy coating ( W v  = 5.15 × 10 -3  m 3 ). The corrosion protection efficiency in corrosive environment of 3.5 wt% NaCl solution was obtained to be >99% for PANI/Gr containing coatings when compared to that of neat epoxy coating. The charge-transfer resistance ( R ct ) of the PANI/Gr containing coatings were estimated to be >10 6 Ω cm 2 , which indicates their highly protective nature when compared to that of neat epoxy coating ( R ct ˜10 5 Ω cm 2 ). Hence, PANI/Gr containing coatings can be potentially used for wear resistance and corrosion protection applications in marine environments.