The vehicle fleet in some regions of the world continues to age, so it is difficult to reduce the consumption of fuels, meet environmental objectives and mitigate the cost it represents. Studies ...exist regarding low mileage vehicles, yet it is important to know the effect generated by high mileage vehicles, which represents a higher percentage in the word. This work was based on the oil degradation. A maximum value of decrease in viscosity of 31% was found, from which the lubrication efficiency of the oil decreases. This also leads to a significant increase in gCO2/km and fuel consumption. In a deeper analysis of the Nissan Tsuru, we found an annual excess of 69.25 Lt of fuel consumption that produces 129.024 Kg additional of CO2 (12.18gCO2/km) with a cost of $1,414.08 Mexican pesos. Due to the average vehicle age in Mexico (15.3 years), these results can be taken as an average for the 45 million plus cars that are currently in circulation. Also, 5.806 million tons of CO2 are generated that represent 3.6% of all current emissions. This leads to a consumption of 3.11 billion liters of fuel at a cost of $63.63 billion Mexican pesos. This methodology can be generalized for different brands of cars and oils in countries with a vehicle fleet similar, in search of improving the monitoring and proper use of automotive oil. In addition, this provides information on the negative effects, so that the countries can establish procedures and strategies for compliance with low pollution policies.
•Procedure to predict fuel economy, CO2 emissions and additional cost for the end user.•The brands analyzed here, belong to a group with average age of 15.3 years.•A minimum of viscosity was found, with a decrease of 27–31%.•Annually in excess, the Tsuru car consumes 69 Lt of fuel and produces 129 Kg of CO2.•With an additional expense of $1,414.08 Mexican pesos (56.92 euros).
The Potassium Titanate-Ti3C2Tx nanocomposite was successfully synthesized by a simple one-step chemical process using Ti3C2Tx and potassium hydroxide at room temperature. Compare to Ti3C2Tx ...nanosheets, the Potassium Titanate-Ti3C2Tx exhibits superior tribological properties.
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A potassium titanate-Ti3C2Tx nanocomposite was synthesized using a facile, low-temperature and environmentally friendly process. The morphology and microstructure of the as-prepared samples were analyzed by means of XRD, SEM, TEM, and XPS. The tribological property of the nanocomposite as additive in base oil was evaluated. The results reveal that the in-situ formed potassium titanate nanowires with average diameter of 30nm and the uniform distribution on the surface of Ti3C2Tx nanosheets. Compare to Ti3C2Tx nanosheets, the average friction coefficient and wear scar width of the oil containing potassium titanate-Ti3C2Tx nanocomposites are decreased by 4.9% and 22% under the same conditions. The excellent tribological performance is attributed to the synergic effects of the two components in the nanocomposite structure.
This paper focuses on the fabrication of a series of TiBN-Cu films with varying B content using a non-equilibrium magnetron sputtering process. The microstructure, mechanical properties, and ...tribological performance under polyalphaolefin(PAO) lubrication of these films were fully investigated. The results indicate that the TiBN-Cu films are composed of fcc-TiN, fccCu, hcp-TiB2, and α-BN. Under PAO6 lubrication, the friction coefficient and wear rate of the TiBN-Cu/PAO composite system first decrease and then slightly increase. The mechanisms behind the enhanced lubrication behavior in terms of wear and friction of the composite system were thoroughly investigated, focusing on the lubrication state, PAO molecular adsorption behavior, and tribochemical products. The lubrication state revealed that the surface roughness of the films directly affects the continuity of the oil film. Calculations of the surface energy revealed that the surface energy of the films decreases gradually with increasing B content, exhibiting oleophilic characteristics that are conducive to the spread of PAO6 on the film's surface. Based on Density functional theory(DFT), calculations of the adsorption energy in the composite system indicated the formation of a robust physicochemical adsorption layer on the surface of the TiBN-Cu/PAO composite. Raman spectroscopy and transmission electron microscope(TEM) analyses of the tribochemical products revealed the in-situ generation of an amorphous carbon‑hydrogen lubricating film with good lubricating performance on the TiBN-Cu composite film under PAO6 lubrication, due to a friction-induced catalytic effect. Additionally, molecular dynamics(MD) simulations based on the theory of molecular dynamics were conducted to explore the degradation process of PAO6 molecules in the solid-liquid composite system under friction, clarifying the “adsorption, dehydrogenation, carbon chain breaking, and carbon chain reconstruction” process in the TiBN-Cu/PAO system. These aspects collectively contribute to enhancing the tribological performance of the TiBN-Cu/PAO composite system. A durable, stable, and efficient TiBN-Cu/PAO solid-liquid composite lubrication system under in-situ and ambient conditions was achieved in this paper.
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•An stable and durable TiBN-Cu/PAO solid-liquid lubrication system in situ at room temperature was accomplished.•The influencing factors of the solid-liquid system were fully investigated regarding to the lubrication state, etc.•The TiBN-Cu/PAO solid-liquid composite lubrication system is excellent in terms of anti-friction and anti-wear.•The tribochemical products from PAO molecules undergo adsorption, dehydrogenation, carbon chain scission and reconstruction.
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•The special shape of the triangle as a surface texture is proposed.•The moving direction of lubricant is from a vertex angle to the opposite side of a triangle.•The die steel surface ...processed through LST first and TiN coatings second has excellent tribological properties.•The single surface modification method should be chosen according to different stamping conditions.
The friction and wear of stamping die surface can affect the service life of stamping die and the quality of stamping products. Surface texturing and surface coating have been widely used to improve the tribological performance of mechanical components. This study experimentally investigated the effect of triangular surface texture on the friction and wear properties of the die steel substrate with TiN coatings under oil lubrication. TiN coatings were deposited on a die steel (50Cr) substrate through a multi-arc ion deposition system, and then triangular surface texturing was fabricated by a laser surface texturing. The friction and wear test was conducted by a UMT-3 pin-on-disk tribometer under different sliding speeds and different applied loads, respectively. The adhesion test was performed to evaluate the effectiveness of triangular texturing on the interfacial bonding strength between the TiN coating and the die steel substrate. Results show that the combination method of surface texturing process and surface coating process has excellent tribological properties (the lowest frictional coefficient and wear volume), compared with the single texturing process or the single coating process. The tribological performance is improved resulting from the high hardness and low elastic modulus of TiN coatings, and the generation of hydrodynamic pressure, function of micro-trap for wear debris and micro-reservoirs for lubricating oil of the triangular surface texture. In addition, the coating bonding strength of the texturing sample is 3.63MPa, higher than that of the single coating sample (3.48MPa), but the mechanisms remain to be further researched.
Sealing engineering equipment, especially in a harsh environment (e.g. high-pressure), is frequently subjected to tribological impacts during service, leading to an accelerated failure of the seal ...parts. In this study, an effective strategy was proposed to reduce the wear of the seal part, utilizing high entropy alloy (HEA) coating. A novel wear-resistant MoNiTaTiV HEA coating was designed and prepared on the substrate of GCr15 steel via laser cladding. The microstructure, chemical composition and microhardness of the HEA coating were examed by scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive spectrometer (EDS) and nanoindentation. The wear property of the HEA coating sliding against its QBe2.0 counterpart under dry and oil-lubricated conditions at high-pressure was investigated deeply. As a result, the HEA coating exhibits BCC and TiN ceramic phases and its hardness reaches approximately 1099.7 HV, which is 3.7 times higher than that of the substrate. Additionally, the HEA coating shows superior wear properties to substrate under dry and oil-lubricated conditions, which is closely related to the high hardness of HEA coating reinforced by TiN particles. The adhesion layer and oxide layer were formed on the HEA coating, transferring the two-body to three-body wear. The QBe2.0 counterpart and MoNiTaTiV coating could be a promising anti-wear tribo-pair for seal parts under dry and oil-lubricated conditions.
•MoNiTaTiV HEA coating is successfully prepared on GCr15 steel substrate using laser cladding.•HEA coating consists of BCC solid-solution phase and TiN ceramic phase.•Hardness of the HEA coating is 1099 HV, about 3.7 times that of the substrate.•HEA coating exhibits excellent high-pressure wear property sliding against QBe2.0 in dry and oil-lubricated conditions.
Steady macroscale superlubricity was firstly achieved on epoxy resin coating lubricated by multiple base oils including nonpolar and polar oils. Hydroxylated tribofilm on counter balls lubricated by ...multiple base oils was observed by TOF-SIMS spectra.
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•Steady macroscale superlubricity was achieved on epoxy resin coating lubricated by multiple base oils.•No obvious run-in stage to superlubricity for the steel/epoxy resin tribopairs lubricated by different base oils.•Soft epoxy resin coating performed superior wear resistance under oil lubrication.•Hydroxylated tribofilm on the counter balls lubricated by multiple base oils was observed by FTIR and TOF-SIMS spectra.
Reducing the friction of base oils to a superlubricity state is highly expected at engineering scale. However, it still is a great challenge for the most of viscous base oils to achieve superlubricity on the conventional tribopairs up to now. Here we report the strategy of solid-oil composited lubrication constructed with an ultra-smooth epoxy resin (EP) coating and base oils for achieving superlubricity. Especially, the frictional results showed that the proposed strategy in this study could be suitable for multiple base oils, including nonpolar and polar base oils as lubricants. The friction coefficient of steel/EP tribopair lubricated by the base oils containing hydroxyl group can be as low as 0.001. Meanwhile, the composited lubrication system did not undergo an obvious running-in stage to achieve the superlubricity state regardless of the type of base oils. The surface hydroxylation of the steel counter ball sliding against EP coating was observed by time-of-flight secondary ion mass spectrometer, even when lubricated by nonpolar base oils without hydroxyl group. This could be a critical factor for the base oils to achieve superlubricity. This finding provides a new and facile approach to realize robust superlubrication for different base oils at engineering scale.
The tribological performance of short glass fibers (SGF), solid lubricants and silica nanoparticles filled epoxy (EP) composites was investigated under oil lubrication conditions. It is demonstrated ...that the addition of SGF greatly reduces the friction and wear of EP. However, further addition of solid lubricants and silica nanoparticles does not change obviously the friction and wear. It is identified that the high tribological performance of SGF reinforced EP is related to the high load carrying capacity and abrasion resistance of SGF. The nanostructure of the tribofilm was comprehensively characterized. It is deemed that the tribofilm plays an important role in the tribological performance by avoiding the direct rubbing of the sliding pairs exposed to boundary and mixed lubrication conditions.
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•Tribological behaviors of short glass fibers (SGF) reinforced epoxy (EP) composites when lubricated with base oil were investigated.•SGF significantly reduces both the friction coefficient and the wear rate of EP under oil lubrication conditions.•The formation of a tribofilm on the metallic counterface and the transfer of materials between composite and counterpart play an important role on the tribological performance.
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•The properties of gun steel were tested in air and simulated seawater environments.•The tribological properties of gun steel after thermal cycling were studied.•Thermal cycle reduces ...the corrosion wear resistance of gun steel.•It provides a basis for the protection of gun steel in the early stage of extrusion.
The influence of gun barrel erosion has been proposed, but the research on the wear behavior of gun steel during the initial extrusion phase remains limited. This study employed an experimental approach to investigate the wear of 30CrNi2MoVA gun steel after untreated (25 °C) and thermal cycling treatments (400 °C and 800 °C) under both air and simulated seawater environments. In the air environment, abrasive wear and adhesive wear mechanisms were prominently observed. In the simulated seawater, abrasive wear mechanism was predominant. In both environments, the surface morphology and wear profiles of the untreated samples were similar, exhibiting a negative interaction phenomenon. After thermal cycling treatment, the corrosion wear resistance of 30CrNi2MoVA steel were significantly reduced. Among them, the material performance is the lowest at 800 °C. Therefore, this study provides theoretical and experimental evidence for improving the friction and wear performance of gun barrel rifling during the bullet extrusion process.
This paper is focused on the experimental determination of the frictional properties of bolts, following the ISO 16047 International Standard. The campaigns involved M14 X 2 8.8 class hexagonal head ...steel screw. Different Design of Experiment techniques were applied to investigate the effects of screw coating and lubrication, along with their interaction. The effect of lubrication was then investigated in further details, comparing two different lubricants and the outcomes of partial lubrication on the underhead or in the threads only. The results indicate that both surface coating and lubrication are highly significant. Regarding lubrication, a ceramic paste by Interflon proved to be highly effective at reducing friction, in particular if applied at the underhead rather than in the threads.
•The tribological response of bolted joints under different conditions was investigated experimentally.•Design of Experiment tools were used to determine the effects of screw surface coating and lubrication.•Zinc-coated screws exhibit a lower friction coefficient with respect to black oxidized ones.•Ceramic paste lubrication, even when performed at the underhead only, is more effective than oil lubrication.•Ceramic paste lubrication in the threads retains a minor importance and is almost ineffective.
In order to improve tribological properties of AISI 4140 steel (AS) for dry/starved lubrication, AS biomimetic self-lubricating material (AS-SACT) was prepared by filling SnAgCu-TiC into biomimetic ...microtextures. Compared with AS, the friction coefficient of AS-SACT was reduced by 5.34% and wear depth was reduced by 62.39% in starved lubrication. Tribological properties of AS-SACT in starved oil are close to those of full oil lubrication. Under starved lubrication, the precipitated lubricant spreads into a 2.2 µm solid film on contact surface. In addition, the lubricant precipitation area forms a 'storage area' for storing lubricating oil and wear debris. The synergistic lubrication effect of multi-solid coating and oil lubrication makes AS-SACT have excellent anti-friction and wear-resisting effect.
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•AS-SACT was designed and prepared by filling SACT into biomimetic microtexture.•The friction properties in starved lubrication are close to those in full oil.•The precipitated lubricants spread into a 2.2 µm solid film on the contact surface.•Lubricant precipitation areas form a 'storage area' for storing oil and wear debris.
