Frictional performances of activated carbon and carbon blacks as lubricant additives

The frictional performances of activated carbon, carbon blacks, mesoporous carbons, and carbon nanotubes were compared as lubricant additives to mineral oils using a ball-on-disk tester at ambient temperature. Well-dispersed, smaller particles with a uniform size were more effective in maintaining the oil gaps and the protecting surfaces. However, the effects of different atomic structures of carbon particles on tribological performances were minimal as long as the particle sizes are of similar order.