Synthesis and tribological properties of oil-soluble copper nanoparticles as environmentally friendly lubricating oil additives
Abstract
Purpose
The purpose of this paper is to synthesize oil-soluble copper (Cu) nanoparticles modified with free phosphorus and sulfur modifier and investigate its tribological properties as environment-friendly lubricating oil additives.
Design/methodology/approach
To improve the anti-oxidation properties of these nanoparticles, two kinds of surface modifiers, oleic acid and oleylamine were used simultaneously. The morphology, composition, structure and thermal properties of as-synthesized Cu nanoparticles were investigated by means of transmission electron microscopy, X-ray powder diffraction, Fourier transform infrared spectrometry and differential thermal and thermogravimetric analysis. The tribological properties of as-synthesized Cu nanoparticles as an additive in liquid paraffin were evaluated with a four-ball friction and wear tester.
Findings
It has been found that an as-synthesized Cu nanoparticle has a size of 2-5 nm and can be well dispersed in organic solvents. Tribological properties evaluation results show that as-synthesized Cu nanoparticles possess excellent anti-wear properties as an additive in liquid paraffin. The reason lies in that as-synthesized surface-capped Cu nanoparticles are able to deposit on sliding steel surface and form a low-shearing-strength protective layer thereon, showing promising application as an environmentally acceptable lubricating oil additive, owing to its free phosphorus and sulfur elements characteristics.
Originality/value
Oil-soluble surface-modified Cu nanoparticles without phosphorus and sulfur were synthesized and its tribological properties as lubricating oil additives were also investigated in this paper. These results could be very helpful for application of Cu nanoparticles as environment-friendly lubricating oil additives.
Keywords
Acknowledgements
The authors acknowledge the financial support of this work by the National 973Project (2007CB607606) and the National Natural Science Foundation of China (51275154).
Citation
Zhang, Y., Xu, Y., Yang, Y., Zhang, S., Zhang, P. and Zhang, Z. (2015), "Synthesis and tribological properties of oil-soluble copper nanoparticles as environmentally friendly lubricating oil additives", Industrial Lubrication and Tribology, Vol. 67 No. 3, pp. 227-232. https://doi.org/10.1108/ILT-10-2012-0098
Publisher
:Emerald Group Publishing Limited
Copyright © 2015, Emerald Group Publishing Limited