Tribological Improvements of Dispersed Nanodiamond Additives in Lubricating Mineral Oil

Abstract

An effort was conducted to study and characterize the effects of nanodiamond particles as an additive to lubricating mineral oil. The tests were run for varying concentrations ranging from pure mineral oil to 0.01% weight-concentration of nanodiamonds. The friction was measured throughout the tests, and the resulting wear was measured with optical profilometry. It was observed that both the average friction coefficient and the wear would decrease proportionally to the concentration of nanodiamond particles, and the 0.01% nanodiamond weight concentration was observed to improve the tribological performance of lubricating mineral oil. Chemical analysis of contacting surfaces showed no significant distinction from the nanodiamond mixture versus the pure mineral oil, while particle size analysis demonstrated that the nanoparticles themselves remained intact (i.e., no breakup) in the contact interface. This helps to conclude that a mechanical and not a chemical effect of the nanodiamond particles helped to protect the metallic surface from wear and improve the lubricating ability of the mineral oil.