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 (Hs) and plowing hardness (Hp), i.e. Hs of 0.43 GPa, and Hp of 0.61 GPa, respectively when compared to that of neat epoxy coating (Hs of 0.17 GPa, and Hp of 0.40 GPa, respectively). Due to their higher Hs and Hp values, PANI/Gr based coatings displayed an enhanced wear resistance (Wear volume, Wv = 4.53 × 10-3 m3) than that of neat epoxy coating (Wv = 5.15 × 10−3 m3). 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 (Rct) of the PANI/Gr containing coatings were estimated to be >106 Ω cm2, which indicates their highly protective nature when compared to that of neat epoxy coating (Rct ˜105 Ω cm2). Hence, PANI/Gr containing coatings can be potentially used for wear resistance and corrosion protection applications in marine environments.