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The unique structure and physical properties of graphene and anatase TiO2 make them suitable for use as additives for engine lubricants. This study describes the use of dielectric barrier discharge plasma-assisted ball milling to synthesize a multilayer graphene-reinforced TiO2 composite nanolubricant additive (MGTC). A variety of physical and chemical tests were performed to characterize the resulting experimental materials, including X-ray diffraction (XRD), Fourier transform infrared (FT-IR), Raman, X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM). Four-ball friction and wear testing machines were used to study the tribological properties and extreme pressure anti-wear properties of a base oil containing 0.1, 0.5, 1.0, and 1.5 wt % of the modified TiO2. Raman spectroscopy, XPS, SEM, and energy-dispersive spectrometry (EDS) analyses were used to examine and analyze the microstructure of the friction pairs. As a result of the plasma-assisted ball milling process, expanded graphite was successfully separated into multilayer graphene nanosheets, and spherical TiO2 was successfully bonded to the nanosheets of the multilayer graphene. The 1.0 wt % composite oil was found to provide good friction reduction and wear resistance. It had a film thickness of 27.5 nm, which was 167% thicker than base oil. Due to its excellent dispersion stability, the MGTC nanocomposite exhibited excellent lubrication performance, which was attributed to the formation of carbon protective films, titanium dioxide deposition films, transfer films, and the occurrence of nano ball effects on the surface of friction pairs.

Poor lubrication performance of low-sulfur fuel leads to increased wear of diesel engine components. In order to improve the lubrication properties of low-sulfur fuel, we successfully prepared graphene lubricant additives by dielectric barrier discharge plasma-assisted ball milling. The tribological properties of graphene lubricant additives in two types of 0# diesel oils with different sulfur content were evaluated by high-frequency reciprocating rig (HFRR). The results indicated that the expanded graphite was exfoliated and refined into graphene sheets with nine layers by the synergistic effect of the heat explosive effect of the discharge plasma, the impact of mechanical milling function, and the cavitation effect of 0# diesel oil. The organic functional groups of 0# diesel oil were successfully grafted on the surface of graphene sheets. The addition of 0.03 wt % graphene resulted in 20% reduction in the friction coefficient (COF) and 28% reduction in wear scar diameter (WSD) compared to pure 0# diesel oil with a sulfur content of 310 mg/kg. The addition of 0.03 wt % graphene resulted in 24% reduction in the friction coefficient (COF) and 30% reduction in wear scar diameter (WSD) compared to pure 0# diesel oil with a sulfur content of 1.1 mg/kg. The formation of graphene tribofilm on rubbing surfaces improved the lubrication properties of low-sulfur fuel.

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In this experimental investigation, a core–shell-structured nano-lubricating additive was synthesized utilizing the dielectric barrier discharge plasma (DBDP)-assisted ball grinding technique for a duration of 5 h. The microstructural analysis of the nano-TiO2 powder was performed employing advanced methods such as X-ray diffraction (XRD) and thermogravimetry–differential scanning calorimetry (TG-DSC). The initial particle size of TiO2 was refined from 1 μm to a range of 150–200 nm, resulting in a remarkable increase in lattice distortion rate by 88.2% and an oil affinity enhancement of 200%. Through the introduction of CTAB’s oil-compatible group onto the surface of nano-TiO2 particles, a modified layer with a thickness of 21 nm possessing superior thermal stability and an activation energy (E a) of 600 kJ/mol was successfully produced. Molecular dynamics simulations were conducted to elucidate the mechanism underlying the surface modification of nano-TiO2 powder facilitated by DBDP-assisted ball grinding, thereby revealing the pivotal role of electrostatic forces in the organic modification of the TiO2 surface. It was found that electrostatic forces dominantly govern the cetyl trimethyl ammonium bromide (CTAB)–TiO2 composite interface model, contributing to 70% of the total energy with a maximum energy proportion of −187.84 kcal/mol. To evaluate the lubrication performance of the composite oil samples under boundary lubrication conditions, comprehensive assessments were carried out using the four-ball method and reciprocating friction experiments. The results demonstrated noteworthy enhancements in viscosity index, dynamic viscosity, and oil film thickness within the composite oil samples. Particularly, the composite oil containing 0.5 wt % TiO2@CTAB exhibited outstanding extreme pressure resistance, manifesting a significant reduction of 41.7% in the average friction coefficient, a considerable increase of 25.8% in wear spot diameter, and a substantial elevation of 66.9% in maximum nonseizure load. Compared to the base oil, the incorporation of 0.5 wt % TiO2@CTAB led to a notable increment of 34.7% in oil film thickness, 6.7% in dynamic viscosity, and 9% in viscosity index. In the tribological experiment simulating marine diesel engines, the friction coefficient witnessed a remarkable reduction by 65.8%, accompanied by a substantial decrease of 54.1% in wear rate. This noteworthy improvement in boundary lubrication conditions of the friction pair effectively mitigated friction and wear. For comprehensive characterization of the wear marks, energy-dispersive spectrometry (EDS) and X-ray photoelectron spectroscopy (XPS) techniques were employed to analyze the physical structure and chemical composition. The implementation of TiO2@CTAB nano-lubricating additives resulted in nanobearing and deposition effects, leading to a reduction in contact area and surface roughness, thereby facilitating the restoration of the friction pairs. These findings possess significant implications for extending the service life of die...

Ferroferric oxide (Fe3O4) is regarded to be a promising high-capacity anode material for LIBs. However, the capacity attenuates fast and the rate performance is poor due to the dramatic pulverization and sluggish charge transfer properties. To solve these problems, a simple in situ encapsulation and composite method was successfully developed to construct carbon nanotube/nanorod/nanosheet-supported Fe3O4 nanoparticles. Owing to the hierarchical architecture design, the novel structure Fe3O4@C nanocomposites effectively enhance the charge transfer, alleviate pulverization, avoid the agglomeration of Fe3O4 nanoparticles, and also provide superior kinetics toward lithium storage, thereby showing significantly improved reversibility and rate performance. The carbon nanotube/nanorod supported core-shell structure Fe3O4@C nanocomposite displays outstanding high rate capability and stable cycling performance (reversible capability of 1006, 552 and 423 mA h g−1 at 0.2, 0.5 and 1 A g−1 after running 100, 300 and 500 cycles, respectively).

Purpose The purpose of this paper is to enhance the characteristics of TiO2 nanoparticles (NPs). Because these NPs stick together easily and are difficult to distribute evenly, they cannot be used extensively in lubricating oils. Altering TiO2 was recommended as an alternate way for making NPs simpler to disperse. Design/methodology/approach Through dielectric barrier discharge plasma (DBDP)-assisted ball mill diagnostics and modeling of molecular dynamics, TiO2@PEG-400 NPs were produced using the DBDP-assisted ball mill. The NPs’ microstructure was examined using FESEM, TEM, XRD, FT-IR and TG-DSC. Using the CFT-1 reciprocating friction tester, the tribological properties of TiO2@PEG-400 NPs as base oil additives were studied. EDS and XPS were used to examine the surface wear of the friction pair. Findings Tribological properties of the modified NPs are vastly superior to those of the original NPs, and the lipophilicity value of TiO2 NPs was improved by 200%. It was determined through tribological testing that TiO2@PEG-400’s exceptional performance might be attributable to a chemical reaction film made up of TiO2, Fe2O3, iron oxide and other organic chemicals. Originality/value This work describes an approach for preventing the aggregation of TiO2 NPs by coating their surface with PEG-400. In addition, the prepared NPs can enhance the tribological performance of lubricating oil. This low-cost, high-performance lubricant additive has tremendous promise for usage in marine engines to minimize operating costs while preserving navigational safety.

With the improvement of request in diesel engine dynamic performance, economical efficiency and emission behavior, test technology of diesel engine has gained extensive attention, which has become one of the hot points in the domestic and international relevant research fields. Among the performance parameters of diesel engine, the instantaneous speed signal contains relevant information about diesel engine combustion and working conditions. As researches show, the instantaneous speed can be used to detect the diesel engine cylinder compression pressure, working nonuniform, combustion difference and other working character. Therefore, the study of instantaneous speed has gradually become a significant technology of non-contact detection. In this paper, the algorithm of instantaneous speed signal is successfully realized under specific sampling frequency. Furthermore, the change law of instantaneous speed curve is compared under different rotate speed. At last, fuel supply of one cylinder is cut off to imitate the misfire fault of diesel engine, and then the fault is successfully diagnosed through the analysis of instantaneous speed. Thus, both the algorithm realization of instantaneous speed and the conclusion related to misfire fault diagnosis can be used to various kinds of diesel engines, which have important project application value.