Optimizing graphene nanoplatelet coating for enhanced wear resistance on copper through electrophoretic deposition parameters

Copper is widely used in several industrial fields due to its excellent thermal and electrical properties. On the other side, weak mechanical properties and wear resistances limit its usage. Low-friction and anti-wear coatings on copper could be a solution to solve those issues. In this work, an anti-wear low-friction graphene nanoplatelets (GNP) coating was successfully obtained on copper substrates through cathodic electrophoretic deposition in a water-based solution. The main aim of this paper was to evaluate the role of deposition times and voltages on the morphology, adhesion, and tribological performances of the coatings. Thus, a full-factorial plan was developed and tested: three deposition times (1, 2, and 3 min) and three voltages (15, 30 and 45 V) were studied. The coatings were tested through a scratch test to assess their adhesion, and their tribological performances were evaluated considering three different normal loads with a ball-on-flat configuration. The analysis of variance showed that both the studied parameters and their interactions were statistically significant for all the evaluated outputs. The results show that the GNP coatings enabled the formation of a tribofilm that lowers the coefficient of friction to approximately 0.12, obtaining a wear resistance improvement of over 88%.