Lubricating behavior of Submicrometer carbon spheres as lubricant additives

Abstract

The purpose of this paper is to evaluate carbon spheres as a green lubricant additive in 5W30 engine oil to reduce friction and wear. Carbon spheres with a diameter of ∼400 nm are synthesized from glucose by using a hydrothermal process. Lubrication is studied using a ball-on-disk tribometer by measuring the friction coefficient and wear in the boundary lubrication regimes. The worn surfaces were analyzed by Raman spectroscopy. Carbon spheres are found to be stably dispersed at 0.5 wt% concentration in base oil. The experiments revealed that carbon spheres are effective in reducing both friction and wear when lubricating by using base oil. Raman results show that the enhanced tribological performance is owing to a carbon-rich boundary film, the formation of which is attributed to the deposit of carbon particles during the sliding process.

Keywords:

• Carbon spheres
• lubricant additive
• tribofilm
• Raman spectroscopy
• tribological performance

Additional information

Funding

This work was supported by National Natural Science Foundation of China (51375249), Key Research & Development Plan of Shandong Province (2017GSF220012), Natural Science Foundation of Shandong Province (ZR2017PEE013) and General Administration of Quality Supervision, Inspection and Quarantine of China (201410083).