Role of graphene additive on wear and electrochemical corrosion behaviour of plasma electrolytic oxidation (PEO) coatings on Mg-MWCNT nanocomposite

Abstract

In this study, wear and electrochemical corrosion behaviour of as-cast magnesium (Mg)/multiwall carbon nanotube (MWCNT) and plasma electrolytic oxidation (PEO) coated Mg/MWCNT samples were evaluated by dry sliding wear tests and potentiodynamic corrosion tests, respectively. In this respect, Mg/MWCNT composite was manufactured by stir casting route. X-ray diffraction (XRD) analysis shows that the presence of Mg, MgO and Mg2SiO4 phases for coated samples. The corrosion rate of the coated samples is about 1.6 times lower than that of un-coated Mg-MWCNT composite. From the wear tests, it is concluded that PEO coating leads to significant improvement in wear resistance in comparison with un-coated Mg/MWCNT composite. It is observed that wear mechanisms are abrasion and oxidation.