Search

At present, due to the excellent properties of graphene, which can significantly enhance the performance of lubricants, researchers are conducting extensive studies on it. However, the poor dispersion of graphene limits its application in lubrication, which becomes an urgent problem for researchers to solve. Moreover, with the concept of green environmental protection becoming more and more popular, the research on water-based lubricants is of great significance. Therefore, we modify three-dimensional graphene (3DG) by polycarboxylate superplasticizer (PCE) to prepare a water-based lubrication nano-additive with long-term dispersion stability, named PCEG. PCEG nanomaterials can stably disperse in water for more than three months, which effectively solves this problem. Tests show that friction coefficient and wear volume of the lubricant with 0.5 wt% PCEG are reduced by 31.1 % and 23.1 %, respectively, compared to the base fluid at 20 N (2.7 GPa) heavy load conditions. The enhanced lubrication performance is attributed to the fact that PCEG, which has excellent dispersion stability, forms a strong adsorption and continuous dense lubrication film on the friction surface. In addition, it fills and polishes the grooves and pits, thus improving the friction-reduction and anti-wear properties. This study not only greatly solves the problem of poor dispersion stability of graphene and develops a nano-lubricant that is consistently effective under heavy load conditions, but also provides an important reference value for the subsequent development of high-performance and stable graphene-based lubricants. [Display omitted] • PCEG with excellent dispersion stability was prepared. • PCEG as an additive improves by 31.1% and 23.1% in friction and wear. • The modification method used in this study is easy to operate and can be applied in large-scale production. • PCEG provides a reference solution the problem of poor dispersion of graphene in water-based lubricants. [ABSTRACT FROM AUTHOR]

Spheroidal carbon particles are touted as excellent additives in lubricants for reduction in friction and wear. Herein 50–100 nm-sized spheroidal carbon soot particles with heliocentric graphitic layers are prepared by controlled decomposition of wasted rubber and subsequent heat-treatment of wasted rubber derived soot. Thermogravimetric analysis showed that the on-set degradation temperature of the soot particles was representative of a material constituted by amorphous and crystalline phases complementing well with x-ray diffraction studies. The soot particles are dispersed in an additive-free base oil (BO), and the soot particles added oil was used as a lubricant. At room temperature, a reduction in coefficient of friction (CoF) and wear scar diameter (WSD) of ~9% and 16.55% were recorded. At a higher temperature of 70 °C, a reduction in CoF and WSD of as high as 48.93% and 28.12% were recorded. Based on the observations, it is theorized that the soot particles acted like nano-bearings between the contacting surfaces producing a rolling effect that efficiently reduced friction and wear concerning the contacting surfaces. Also, the dispersion of soot particles improved the viscosity retention of BO at higher temperatures indicating its multifunctional ability. [Display omitted] • 50–100 nm-sized carbon soot particles with sphere-like morphology are prepared from wasted rubber. • Heliocentric graphitic layers constituted the soot particles. • The carbon soot particles had a mixture of crystalline and amorphous characteristics. • The carbon soot particles are dispersed in an additive-free Group-2 dewaxed lubricating oil. • Carbon soot particles are an excellent additive in lubricating oil for considerable friction and wear reduction. [ABSTRACT FROM AUTHOR]