Tribological characterization of M50 matrix composites reinforced by TiO2/graphene nanomaterials in dry conditions under different speeds and loads

This paper investigated the tribological characterization of M50 composite manufactured with TiO2/graphene hybrid nano-additives (M50TG) slid against a stationary silicon nitride (Si3N4) ball in dry conditions under various loads and speeds. The frictional specimens (M50 and M50TG) were fabricated using spark plasma sintering (SPS). The tribological tests were investigated using pin-on-disk tribometer. The phases and crystalline structures of the fabrication M50 and M50TG composites was analyzed using x-ray diffraction (XRD). Furthermore, the frictional surfaces were examined using electron probe microanalysis (EPMA), energy-dispersive spectroscopy (EDS), and Raman spectrometry to elucidated the wear mechanisms and differentiate chemical structures of the self-lubricating layer. The results elucidated that the friction coefficient (FC) and wear rate (WR) of the M50TG composite reduced by 24%-40% and 45%-92%, respectively, as compared to the M50 without nano-additives. The morphological analysis illustrates that this is attributed to the lubricating layer producing on the rubbing interfaces. Hence, M50TG composite possessed excellent self-lubricating characteristics.