The synergistic effect of MAO-treated and PAO–graphene oil on tribological properties of Ti6Al4V alloys

In this study, micro-arc oxidation (MAO) coatings were fabricated and modified graphene (MGr) was used as an oil additive to enhance the tribological properties of Ti6Al4V. The results show that: the friction coefficient of Ti6Al4V is significantly reduced when lubricated by the modified oil, and the friction coefficients of the MAO coatings are much lower than those of Ti6Al4V with Polyα olefin synthetic oils that are added with modified graphene (PAO–MGr). The mainly wear form of Ti6Al4V is mainly adhesive, while that of the MAO coating is abrasive. Furthermore, the peaks of typical graphene were observed in the friction region using Raman spectroscopy. The modified graphene enters the porous structure of the MAO coating and forms a stable graphene transfer film, thereby achieving a low friction coefficient and wear.