Effect of Different Morphology Carbon-Based Nanomaterials Addition on Tribological Properties of Refrigeration Oil

Nano refrigerating oil was prepared by adding three kinds of carbon-based nanomaterials with different morphology, namely zero-dimensional spherical fullerenes (CB), one-dimensional carbon nanotubes (CNTs) and two-dimensional layered graphene (GE). The change of friction coefficient of steel ball and steel disc friction pair and wear behaviors of steel disk under the lubrication condition of refrigerated oil with different mass fractions (0.01%–0.10%) of carbon-based nanomaterials was studied. The results show that with the increase of the content of carbon-based nanomaterials, the average friction coefficient decreased first and then increased, and the wear volume basically first increased, then decreased and then increased. The average friction coefficients of the friction pairs were the smallest when the mass fractions of zero-dimensional spherical CB, one-dimensional CNTs, and two-dimensional layered GE were 0.02%, 0.05%, and 0.02%, which were reduced by 10%, 12%, and 12% compared with those under the pure refrigerated oil lubrication condition, respectively. The ability of zero-dimensional spherical CB to reduce the friction coefficient was weak, while the ability of one-dimensional CNTs and two-dimensional layered GE was strong, and a lower content of two-dimensional layered GE could achieve the antifriction effect of a higher content of one-dimensional CNTs. When the mass fractions of zero-dimensional spherical CB, one-dimensional CNTs and two-dimensional layered GE were 0.02%, 0.03%–0.05% and 0.02%–0.05%, the wear volumes were the smallest, which were reduced by about 59%, 8% and 36% compared with those under the pure refrigerated oil lubrication condition, respectively. The two-dimensional layered GE had the best comprehensive anti-friction effect, and the friction coefficient of the friction pair was the most stable and the wear volume was small under the condition of refrigeration oil lubrication with GE.