Interaction of novel lubricant additives based on MoS_2 nanotubes with non-ferrous tribological materials

摘要

MoS_2 nanotubes (NTs) are novel lubricant additives reducing friction and wear of mechanical components made of steel. Nowadays, non-ferrous surfaces are becoming more widely used, mainly as multifunctional coatings working in configuration with a steel pair. As a consequence, the purpose of this work is to reveal the interaction mechanism of nanoparticles with coated elements in lubricated contacts that are essential in future lubrication technologies. The tribological properties were investigated using a reciprocating sliding testing machine in a steel-ball-on-coated-disc configuration. For tribological studies, two commercially available coatings were selected: WC/C and DLC coating. Frictional results show only slight improvement for lubricant blends containing MoS_2 nanotubes with selected coatings, and wear tracks are surprisingly very extensive when compare to oils with additives. Generally, the presence of coating in any tribological test configurations diminish the effectiveness of MoS_2 NTs when compare to steel/steel contact. Chemical analytics show that interaction mechanisms of the nanotubes and surface changes, depending on the coating material, have the ability to form a chemically derived tribofilm.