Candle Soot as Particular Lubricant Additives

An onion-like carbon material was prepared from candle soot, and its tribological properties as an additive were investigated in water. The material assumed a spherical shape with a layered nanostructure based on high-resolution transmission electron microscopic analysis and had considerable sp² hybrid carbon as revealed by Raman spectroscopy. The tribological properties were determined on an optimal SRV-IV oscillating reciprocating friction and wear tester. The results indicate that these candle soots as additives are able to effectively reduce both the friction and wear of sliding pairs in water. In addition, the chemical reactivity, physical stability, surface charge, and size of candle soot had a key impact on their lubrication properties. Based on our characterization of the wear scars by scanning electron microscopy and in situ Raman spectroscopy, we suggest a rolling and sliding lubrication mechanism.