Effect of surfactants on the tribological behavior of organic carbon nanotubes particles additive under boundary lubrication conditions

Abstract

The tribological enhancement of nano-lubricant that consist of formulated Eichhornia Crassipes carbon nanotubes (EC-CNTs) dispersed in base rapeseed oil using sodium dodecyl sulfate (SDS) and oleic acid (OA) as surfactants was conducted in this study. The experiment was done using high frequency reciprocating rig, applying 0.5 mass%, 1 mass% and 1.5 mass% EC-CNTs alongside 2% and 5% of the various surfactants and sonicated for 25 minutes and 50 minutes respectively. The use of surfactants and sonication was to reduce agglomeration. The outcome showed that SDS yielded better results than OA, further revealed that the use of 2% SDS under sonication time of 50 minutes reduced the solution agglomeration compared to 5% SDS and sonication time of 25 minutes. The tribological test conducted on EC-CNTs concentration effects was based on friction and wear reduction, load carrying ability, lubricant film stability, wear scar micrograph and mechanism of particles. The results indicated that inclusion of nanoparticles substantially enhanced the tribological characteristics. However, pronounced enhancement was recorded with 1 mass% EC-CNT compared to counterpart lubricants. Friction and wear reduction by 1 mass% EC-CNT were 65.4% and 63.6% respectively against base oil. The nanoparticles exhibited excellent mechanism for which the tribological enhancement was achieved.