Effect of dispersant agent in antiwear ability of oxides nanoparticles in lubricants
Valdicleide Silva e Mello1; Edália Azevedo de Faria1; Diana Roberta da Silva Medeiros1; Salete Martins Alves1
1 Universidade Federal do Rio Grande do Norte
doi:10.20906/CPS/COB-2015-0560
Resumo
Oxide nanoparticles (NNP) have been used as extreme pressure additives in boundary lubrication, with good results. However, the major challenge of this technology is to control the NNP dispersion in base oil. An uncontrolled agglomeration of these nanoparticles may cancel its antiwear ability, besides they can increase the friction between metallic surfaces. This article aims to study the effect of organic dispersants to enable a better performance from NNP as an antiwear additive in lubricants. Copper oxides at the nanoscale were dispersed in lubricant base with using three organic solvents as dispersive agents (Toluene, Hexane and Ethylene Glycol). The dispersion was evaluated by UV visible spectroscopy tests and optical miscroscopy. The dispersed samples were submitted to a test with relative contact between two metal surfaces to verify the effect on the antiwear action. The tribological tests were carried out in HFRR tribometer. The UV visible results showed more uniform size distribution of the NNP dispersed in lubricant oil when toluene was dispersant agent. Furthermore, this dispersant provided a substantial decrease of the coefficient of friction, as well lower abrasion losses in the tribological tests.
Palavras-chave: Nanoparticles; Dispersant; Friction reduction