Nitrogen-Phosphorus Codoped Carbon Nanospheres as Lubricant Additives for Antiwear and Friction Reduction

Abstract

Nitrogen and phosphorus doping have been proven to be effective strategies for improving the tribological properties of carbon-based materials when used as lubricating oil additives. Herein, an efficient strategy is demonstrated for the preparation of nitrogen and phosphorus codoped organic carbon nanospheres (denote as N, P@CN) via a template-free interfacial copolymerization combined with ammonium hypophosphite-assisted carbonization. The N and P are found to be homogeneously distributed through the entire carbon shell. The tribological properties of as-prepared materials as base oil additives under different test conditions were evaluated. The as-prepared N, P@CNs exhibit good dispersibility and stability in base oil due to the presence of many organic functional groups. Moreover, they are considered to be thermal stable at elevated temperatures, and the existing robust structure makes them favorable as lubricant additives. The experiment results show that the friction reduction and wear resistance abilities of N, P@CNs were superior to that of pure base oil, because N, P@CNs can induce tribo-chemical reactions to form a protective film on the interfaces due to the combined effect of nitrogen and phosphorus. The obtained N, P@CNs could increase the load carrying capacity of base oil from 250 N to 1050 N. The coefficient of friction can be reduced to 0.08, and the corresponding wear volume loss can be decreased by 90%. These findings open up a possibility to prepare environmentally friendly lubricant additives, such as carbon nanospheres doped with other elements, to achieve excellent antiwear and friction-reducing characteristics.

Dialkyl Dithiophosphate-Functionalized Ti3C2Tx MXene Nanosheets as Effective Lubricant Additives for Antiwear and Friction Reduction

“…The peaks of Fe 2p at 708.6 and 710.8 eV in Figure c can be assigned to elemental iron and iron oxides (Fe 2 O 3 and Fe 3 O 4 ). The peaks at 709.8 and 713.2 eV can be assigned to ferrous sulfide and iron phosphate. , Furthermore, as shown in Figure d, the peaks of Ti 2p on the worn surface at 463.8 and 459.9 eV can be attributed to the formation of titanium oxide. The peaks of Ti 2p at 461.1 and 458.1 eV are attributed to the damaged Ti 3 C 2 T x fragments under a high load.…”

Dialkyl Dithiophosphate-Functionalized Gallium-Based Liquid-Metal Nanodroplets as Lubricant Additives for Antiwear and Friction Reduction

“…Even though the nanoparticles illustrate an impressive reduction in wear and friction of mechanical systems, there have been very few commercial applications . The chief constraints include cost-effectiveness, ambiguous performance, toxicity, and corrigible dispersion stability. − Therefore, to optimize the implementation of classic additives, exploring several upcoming additives may break a new ground.…”

Nitrogen–phosphorus doped graphitic nano onion-like structures: experimental and theoretical studies

“…Graphitic nano onion-like particles (GNOs) have attracted attention due to their high surface area, low density, high-temperature stability, and excellent electrical conductivity. 1 GNOs have been used in lithium batteries, 2 supercapacitors, 3 drug delivery, 4 lubricants, 5,6 catalyst supports, 7,8 and removal of contaminants from water. 9 GNOs have been synthesized using different routes such as arc-discharge, 10 laser ablation, 11 and chemical vapor deposition.…”