Effect of Graphene Addition to Lithium-Based Grease on the Performance of Rolling Element Bearings

Abstract

Recent research attempts have shown that graphene as a lubricant nanoadditive provides excellent tribological behaviour in mechanical applications due to its outstanding properties represented in its self-lubricating nature. In this work, a set of deep groove ball bearings lubricated using lithium-based grease mixed with different contents of reduced graphene oxide (rGO) were tested through a specially designed test rig under different loading conditions. The rGO additions were varied to include 0.5, 1, 2, 3.5, and 5 wt.%. The consumed power is introduced for the first time as a measure of lubrication efficiency. The results demonstrate that the addition of rGO reduces the consumed power required to drive the rotor under the applied test load. The most considerable power saving is obtained after adding 2wt.% rGO to grease, which has reduced the consumed power down to about one-fourth of that consumed using grease only. Also, the vibration levels were measured and analysed for each lubrication and loading condition.