As moving mechanical systems, including transportation vehicles, become increasingly electrified, there is a growing need for novel experimental methods capable of assessing the critical performance characteristics of lubricants under both mechanical and electrical loads. Simultaneously, the development of electro-sensitive lubricants, which are blended with nanoparticles, ionic liquids, and other additives requires more advanced tribological tools and methods to fully assess their potential under electrical stimulation. In this work, we study the lubrication behavior of a graphene-based nanolubricant using a modified mini-traction machine (MTM) that enables precise flow of electrical current through the rolling¿sliding contacts (electrified traction test). For this purpose, a low-viscosity polyalphaolefin oil (PAO4) was mixed with graphene nanoplatelets (GnPs) and tested at 20 °C and 75 °C, under both non-electrified and electrified conditions (0 and 1.5 A). The results indicate that electrical current significantly alters the viscosity, traction, and wear characteristics of the GnP-based nanolubricant. In particular, adding GnPs improves resistance to interfacial shear at medium-to-high rolling speeds while also facilitating easier slippage and shear under boundary-mixed lubrication conditions. Conversely, under high-shear, high-pressure, and electrified conditions, carbon-based tribofilms can be mechanically unstable and contribute to the possible formation of carbonaceous debris, which could trigger abrasive interactions. This contrasting behavior highlights the dual role of GnPs in electrical environments and emphasizes the need for more effective nanolubrication strategies to fully harness their potential for electro-stimulating environments. Overall, the electrified mini-traction tests provide a highly sensitive and reliable method for screening the performance characteristics of candidate lubricants and thus guiding the development of next-generation electro-sensitive lubricants with superior performance.
