Journal Published Online: 29 May 2018
Volume 7, Issue 3

Nanolubrication Mechanisms: Influence of Size and Concentration of CuO Nanoparticles



In nanolubrication, friction-reduction and anti-wear behaviors are dependent on the characteristics of nanoparticles, such as size, shape, and concentration. Some mechanisms of friction-reduction and anti-wear of NNP in lubricant have been reported as protective film, rolling effect, polishing or smoothing effect, mending effect, and the third body. Thus, this work studied differences in nanolubrication mechanism as functions of size and concentration of CuO NNP added in synthetic oil. Three levels of concentration and size were evaluated: 0.1, 0.25, and 0.5 % wt., and 2.5, 4.4, and 8.7 nm, respectively. The methodology was divided into three steps: first, the preparation of CuO NNP from an alcohol-thermal method. These were characterized by XRD (X-ray diffraction) and TEM (Transmission electron microscopy). The second part was constituted by evaluation of lubricant with NNP by a tribological test, which was carried out under boundary lubrication conditions in high frequency reciprocating rig (HFRR) equipment. The last step was the characterization of the wear mechanism; scanning electron microscopy (SEM) and Raman spectroscopy aided to identify tribochemistry interactions between nanolubricant and steel surface. The results showed that the concentration of NNP influenced wear: low concentration decreased the wear and promoted a smooth surface, while more plastic deformation was observed in high concentration. For the NNP size, the smallest size corresponded to the lowest friction coefficient. The best results were obtained for nanolubricant with a concentration of 0.1 % wt. and a NNP size of 2.5 nm.

Author Information

Alves, Salete Martins
Science and Technology School, Federal University of Rio Grande do Norte, Natal, RN, Brazil
Silva e Mello, Valdicleide
Department of Mechanical Engineering, Federal University of Rio Grande do Norte, Natal, RN, Brazil
Sinatora, Amilton
Department of Mechanical Engineering, University of São Paulo, São Paulo, SP, Brazil
Pages: 16
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Stock #: MPC20170064
ISSN: 2379-1365
DOI: 10.1520/MPC20170064