The Effect of Carbon Nanotubes Based Nanolubricant on Stick-Slip Behavior

In this article, stick-slip behavior of a metal-metal interface is investigated in presence of a lubricant mixed with multiwalled carbon nanotubes (MWCNTs). The friction experiments are carried out to determine the critical pulling velocity at which stick-slip motion disappears and steady sliding follows thereafter. The sliding experiments show that the critical velocity decreases with increase in concentration of MWCNTs in the lubricant up to 1.6% (wt./vol.), but further addition of the nanoparticles in the lubricant leads to increase in the critical velocity. Also, the critical velocity is found to be nearly independent of normal stress at the optimal concentration of the nanoparticles. Moreover, amplitude of stick-slip motion decreases with increase in concentration of MWCNTs up to the optimal value at a fixed velocity but the same begin to increase after the optimal concentration. The results are explained in light of the rolling-sliding mechanism of the spherical or cylindrical nanoparticles reported in literature. The present study reveals that the stick-slip instability can also be eliminated by using an optimal concentration of the nanoparticles in the lubricant.