Search Results (42)

The accurate and precise measurement of lubricating oil consumption is critical for developing environmentally friendly internal combustion engines, particularly hydrogen-fueled internal combustion engines. The deuterium tracer method is based on the addition of poly-deuterated base oil tracers to fully formulated oils for precise, accurate, and fast lubricating oil consumption measurements. Previously performed measurements have shown that the use of poly-deuterated poly-alpha olefins has minimal impact on lubricating oil properties, except for a slight drop in oil viscosity. To further reduce the impact on lubricating oil characteristics, a new base oil for the synthesis of a poly-deuterated tracer is introduced, and its influence on the lubricating oil’s chemical, tribological, and rheological properties is analyzed. Furthermore, the influence of the tracer addition on the preignition tendencies of the fully formulated oil is also examined. Based on the analyses, no relevant changes in the lubricating oil properties, such as viscosity, density, and thermal degradation behavior, can be observed. Additionally, the deuterium tracer does not negatively influence combustion anomalies, thus reducing preignition tendencies. These results establish the method’s compatibility with new-generation engines, especially hydrogen-fueled internal combustion engines. Full article

Graphene oxide (GO), a derivative of graphene, has attracted significant attention in tribological applications due to its unique structural, mechanical, and chemical properties. This review highlights the influence of GO and its composites on friction and wear performance across various engineering systems. The paper explores GO’s key properties, such as its high surface area, layered morphology, and abundant functional groups. These features contribute to reduced shear resistance, tribofilm formation, and improved load-bearing capacity. A detailed analysis of GO-based composites, including polymer, metal, and ceramic matrices, reveals those small additions of GO (typically 0.1–2 wt%) result in substantial reductions in coefficient of friction and wear rate, with improvements ranging between 30–70%, depending on the application. The tribological mechanisms, including self-lubrication, dispersion, thermal stability, and interface interactions, are discussed to provide insights into performance enhancement. Furthermore, the effects of electrochemical environment, functional group modifications, and external loading conditions on GO’s tribological behavior are examined. Despite these advantages, challenges such as scalability, agglomeration, and material compatibility persist. Overall, the paper demonstrates that GO is a promising additive for advanced tribological systems, while also identifying key limitations and future research directions. Full article

The advancement of next-generation lubricants is pivotal for enhancing energy efficiency and mitigating environmental impacts across diverse industrial applications. This review systematically examines recent developments in lubricant technologies, with a particular focus on sustainable strategies incorporating bio-based feedstocks, nanostructured additives, and hybrid formulations. These innovations are designed to reduce friction and wear, decrease energy consumption, and prolong the operational lifespan of mechanical systems. A critical assessment of tribological behavior, environmental compatibility, and functional performance is presented. Furthermore, the integration of artificial intelligence (AI) into lubricant formulation and performance prediction is explored, highlighting its potential to accelerate development cycles and enable application-specific optimization through data-driven approaches. The findings emphasize the strategic role of eco-innovative lubricants in supporting low-carbon technologies and facilitating the transition toward sustainable energy systems. Full article

This study systematically investigates the influence of nitrogen (N₂) flow rates and nitrocarburized (PNC) interlayers on the mechanical and tribological properties of TiAlN coatings deposited on 300M steel substrates via magnetron sputtering. The coatings were fabricated under three N₂ flow rates (30, 90, and 150 sccm), with microstructure evolution, elemental composition, and phase transitions analyzed using SEM, EDS, AFM, and XRD. The results indicate that the PNC/TiAlN composite coatings exhibited superior interfacial adhesion and load-bearing capacity compared to standalone TiAlN coatings, attributed to the graded hardness transition and stress distribution optimization at the coating–substrate interface. Nanoindentation tests revealed enhanced hardness and elastic modulus in PNC/TiAlN systems under high N₂ flow conditions. Tribological evaluations demonstrated that the composite coatings achieved lower specific wear rates (25.23 × 10⁻⁸ mm³·N⁻¹·m⁻¹) under 7.3 N, outperforming monolithic TiAlN coatings by mitigating abrasive wear and delamination. The synergy between N₂ flow modulation and nitrocarburizing pretreatment effectively optimized coating–substrate compatibility, establishing a robust framework for designing wear-resistant TiAlN coatings in extreme service environments. This work provides critical insights into tailoring PVD coating architectures for aerospace and heavy-load applications. Full article

Poly(phenylene sulfide) (PPS) is a high-performance thermoplastic engineering material with excellent comprehensive performance that finds application in many fields due to its good processability, excellent heat resistance, and mechanical properties. However, the poor friction and wear properties of PPS limit its wide application in industrial sectors. In this work, polytetrafluoroethylene (PTFE) was adopted as the solid tribo-modifier to improve the tribological performance of PPS. The efficacy of using three types of PTFE fillers, namely PTFE fiber, micropowder, and nanopowder, was comparatively investigated. The results revealed that the incorporation of PTFE was beneficial to improving the tribological properties of PPS and PTFE nanopowders, which were prepared by irradiation treatment technology that demonstrated the best modification effect in terms of both tribological and mechanical performance among the studied systems. In addition, the coefficient of friction and specific wear rate of PPS composites with 30 wt% nanopowders reached 0.165 and 3.59 × 10⁻⁵ mm³/Nm, respectively, which were 70.7% and 99.0% lower than their pure PPS counterparts. The above finding was attributed to the improved compatibility between the PTFE nanopowders and the PPS substrate as well as the easier formation of intact PTFE transfer film on the contact surface. This work shows some perspective for designing self-lubricating polymer composites that broaden their application in industrial sectors. Full article

The advancement of 3D printing technology has changed material design and fabrication across various industries. Among its many applications, the development of high-wear-resistance polymer composites, particularly using Fused Deposition Modelling (FDM), has received increasing interest from both academic and industrial sectors. This paper provides an overview of recent advances in this field, focusing on the selection of key printing parameters (such as layer thickness, print speed, infill density, and printing temperature) and material compatibility optimisation to enhance print quality and tribological performance. The effects of various tribo-fillers, such as fibres and nanoparticles, on the tribological properties of the printed polymer composites were studied. Generally, in the case of nano-sized particles, the wear rate can be reduced by approximately 3 to 5 times when the nanoparticle content is below 5 vol.%. However, when the nanoparticle concentration exceeds 10 vol.%, wear resistance may deteriorate due to the formation of agglomerates, which disrupts the uniform dispersion of reinforcements and weakens the composite structure. Similarly, in short fibre-reinforced polymer composites, a fibre content of 10–30 vol.% has been observed to result in a 3 to 10 times reduction in wear rate. Special attention is given to the synergistic effects of combining micro- and nano-sized fillers. These advancements introduce novel strategies for designing wear-resistant polymer composites without requiring filament fabrication, making 3D printing more accessible for tribological applications. In the last part of the review, the impact of emerging AI technologies on the field is also reviewed and discussed. By identifying key research gaps and future directions, this review aims to drive further innovation in the development of durable, high-performance materials for wide industry applications in aerospace, biomedical, and industrial engineering. Full article

The enhancement of tribological properties represents a pivotal strategy for achieving energy efficiency and environmental protection. Titanium dioxide (TiO₂) nanomaterials have been garnering significant attention due to their exemplary tribological properties and due to the abundance of titanium reserves. The present review is concerned with the study of TiO₂ nanomaterials in lubricants. The properties and various synthesis methods of TiO₂ nanomaterials are presented. The dispersion stability of these TiO₂ nanomaterials in lubricating oils is discussed in depth, as well as strategies to improve their dispersion stability, such as enhancing compatibility with base oils, reducing the dynamic light scattering (DLS) particle size, modulating the zeta potential, and optimizing the drying step. Aggregation and dispersion instability remain key challenges for TiO₂ nanomaterials, especially bare TiO₂ nanoparticles (NPs). In contrast, in situ surface-modified TiO₂ NPs show improved stability and tribological performance, offering promise for further research. The tribological performance of lubricants has been demonstrated to be enhanced by TiO₂ nanomaterials, with the observed enhancement attributed to the synergistic effect of multiple mechanisms, including rolling, patching, polishing, and the formation of a protective film. Furthermore, future research suggestions are proposed to provide a reference for the design and synthesis of high-performance TiO₂ nano-lubricants and promote their wide application. Full article

To address the issue of high wear of polymer composites during friction, WSe₂ nanofillers were incorporated into the polymer matrix as a reinforcing phase to enhance heat transfer and improve the composites’ wear resistance. Tannic acid (TA) was grafted onto the surface of WSe₂ through high-energy ball milling, which facilitated the exfoliation of the nanofillers and improved their interfacial compatibility with the matrix material. Tribological experiments revealed that adding 5 wt% TA-WSe₂ reduced the friction coefficient and volumetric wear rate to 0.0065 and 8.7 × 10⁻⁴ μm³/N·m, respectively, representing reductions of 98% and 94% compared to pure PEI. The TA-WSe₂ not only served as a reinforcing phase to enhance heat transfer but also facilitated the timely dissipation of heat generated during friction. Additionally, it formed strong interfacial bonds with both PEI and PTFE, allowing the applied load to be efficiently distributed throughout the composite material. This study offers a practical approach for the functionalization of WSe₂ and the development of ternary composite materials for tribological applications. Full article

Corn stalk fibers extracted from cattle manure (CSFCM) represent a unique class of natural fibers that undergo biological pre-treatment during ruminant digestion. This study systematically investigates the optimization of CSFCM-reinforced friction materials through controlled silane treatment (2–10 wt.%). The biological pre-treatment through ruminant digestion creates distinctive fiber properties that influence subsequent chemical modification. Physical characterization revealed that optimized interface modification at 6 wt.% silane treatment (CSFCM-3) effectively enhanced the fiber–matrix compatibility while achieving a 34.2% reduction in water absorption and decreased apparent porosity from 9.03% to 7.85%. Tribological evaluation demonstrated superior performance stability, with CSFCM-3 maintaining friction coefficients of 0.35–0.45 across 100–350 °C and exhibiting enhanced thermal stability through a fade ratio of 14.48% and recovery ratio of 95%. The total wear rate showed significant improvement, reducing by 26.26% to 3.433 × 10⁻⁷ cm³ (N·m)⁻¹ compared to untreated specimens. Microscopic analysis confirmed that the optimized silane modification promoted the formation of stable secondary plateaus and uniform wear patterns, contributing to enhanced tribological performance. This investigation establishes an effective approach for developing high-performance friction materials through precise control of silane treatment parameters. The findings demonstrate the potential for developing sustainable friction materials with enhanced performance characteristics, offering new pathways for eco-friendly material design that effectively utilizes agricultural waste resources. Full article

Manufacturing sectors, including automotive, aerospace, military, and aviation, are paying close attention to the increasing need for composite materials with better characteristics. Composite materials are significantly used in industry owing to their high-quality, low-cost materials with outstanding characteristics and low weight. Hence, aluminum-based materials are preferred over other traditional materials owing to their low cost, great wear resistance, and excellent strength-to-weight ratio. However, the mechanical characteristics and wear behavior of the Al-based materials can be further improved by using suitable reinforcing agents. The various reinforcing agents, including whiskers, particulates, continuous fibers, and discontinuous fibers, are widely used owing to enhanced tribological and mechanical behavior comparable to bare Al alloy. Further, the advancement in the overall characteristics of the composite material can be obtained by optimizing the process parameters of the processing approach and the amount and types of reinforcement. Amongst the various available techniques, stir casting is the most suitable technique for the manufacturing of composite material. The amount of reinforcement controls the porosity (%) of the composite, while the types of reinforcement identify the compatibility with Al alloy through improvement in the overall characteristics of the composites. Fly ash, SiC, TiC, Al₂O₃, TiO₂, B₄C, etc. are the most commonly used reinforcing agents in AMMCs (aluminum metal matrix composites). The current research emphasizes how different forms of reinforcement affect AMMCs and evaluates reinforcement influence on the mechanical and tribo characteristics of composite material. Full article

SiC multiphase ceramics were prepared via spark plasma sintering using AlN and TiB₂ as the second phase and Y₂O₃ as a sintering additive. The effects of TiB₂ content (10 vol.% and 20 vol.%) and sintering temperature (1900 °C to 2100 °C) on the phase composition, microstructure, and mechanical and tribological properties of SiC multiphase ceramics were investigated. The results showed that Y₂O₃ reacts with Al₂O₃ on the surface of AlN to form the intercrystalline phase Y₄Al₂O₉ (YAM), which promotes the densification of the multiphase ceramics. The highest density of SiC multiphase ceramics was achieved at 10 vol.% TiB₂ content. Moreover, TiB₂ and SiC exhibited good interfacial compatibility. In turn, a thin solid-solution layer (~50 nm) was formed by SiC and AlN at the interface. The periodic structure of SiC prevented the dislocation movement and inhibited the base plane slip. The most optimal mechanic characteristics (a density of 98.3%, hardness of 28 GPa, fracture toughness of 5.7 MPa·m^1/2, and bending strength of 553 MPa) were attained at the TiB₂ content of 10 vol.%. The specific wear rates of SiC multiphase ceramics were (4–8) × 10⁻⁵ mm³/N·m at 25 °C and 2.5 × 10⁻⁵ mm³/N·m at 600 °C. The wear mechanism changed from abrasion at 25 °C to a tribo-chemical reaction at 600 °C. Therefore, adding lubricious oxides of TiB₂ is beneficial for the improvement in wear resistance of SiC ceramics at 600 °C. Full article

In the field of industrial lubrication, solid–liquid composite lubrication (SLCL) techniques based on diamond-like carbon (DLC) coatings and lubricating oils are emerging recently, which may be applied in many fields in the near future, especially automotive industries. The tribological behaviors of SLCL systems depend strongly on the compatibility between DLC coatings and oils. This review describes the advantages of SLCL techniques by pointing out the synergistic effects between DLC coatings and lubricating oils. Then the main factors determining the tribological performance of SLCL systems are discussed in detail. Finally, a conclusion about the characteristics of reported SLCL systems is made, and a prospect about the potential development of SLCL technology is proposed. On the basis of the relevant literature, it could be found that the tribological properties of SLCL systems were influenced by many more factors compared with individual DLC lubrication or individual oil lubrication due to the complicated tribo-chemical reactions involving DLC and oil during friction. And under some optimized working conditions, the tribological performances of SLCL systems (friction and wear reduction) are superior to individual DLC lubrication and individual oil lubrication. However, the tribological performance of SLCL systems needs to be further improved (for example, to achieve superlubricity and ultra-low wear simultaneously) by adjusting the structures of DLC coatings, regulating the compositions of oils, and most importantly, enhancing the physicochemical and tribological synergies between DLC coatings and oils. This review provides a comprehensive understanding of the SLCL technology, which may be very helpful for the researchers and engineers in the field of industrial lubrication and tribology. Full article

In this study, we fabricated Ti-Cu-based friction composites containing waste-metal (Ti, CuZn, stainless steel (SSt), MgAl), Al₂O₃ due to improving properties and its good compatibility with copper and graphene nanoplatelets as reinforcement and lubricant component, using planetary ball mill and technique based on Spark Plasma Sintering (SPS). Understanding the wear behaviour of such engineered friction composites is essential to improve their material design and safety, as these materials could have the potential for use in public and industrial transportation, such as high-speed rail trains and aircraft or cars. This is why our study is focused on wear behaviour during friction between function parts of devices. We investigated the composite materials designed by us in order to clarify their microstructural state and mechanical properties. Using different loading conditions, we determined the Coefficient of Friction (COF) using a ball-on-disc tribological test. We analysed the state of the samples after the mentioned test using a Scanning Electron Microscope (SEM), then Energy-Dispersive X-ray Spectroscopy (EDS), and confocal microscopy. Also, a comparative analysis of friction properties with previously studied materials was performed. The results showed that friction composites with different compositions, despite the same conditions of their compaction during sintering, can be defined by different wear characteristics. Our study can potentially have a significant contribution to the understanding of wear mechanisms of Ti-Cu-based composites with incorporated metal-waste and to improving their material design and performance. Also, it can give us information about the possibilities of reusing metal-waste from different machining operations. Full article

The continuous development of biomedical materials necessitates exploring new solutions to enhance implant performance. This study investigates the impact of titanium dioxide nanoparticles on calcium phosphate coatings applied to VT1-0 titanium substrates using micro-arc oxidation. Titanium, widely recognized for its excellent mechanical properties and compatibility, serves as an ideal substrate for implants. The coatings were synthesized in an electrolyte with varying titanium dioxide concentrations to examine their influence on surface morphology, wettability, roughness, hardness, and tribological characteristics. Characterization techniques, such as scanning electron microscopy, X-ray diffraction, and profilometry, were employed to analyze the coatings’ structural and mechanical properties. The results demonstrate that increasing titanium dioxide concentrations leads to enhanced uniformity, reduced pore sizes, and higher hardness. Furthermore, the coatings showed improved wear resistance and reductions in friction coefficients at optimal nanoparticle levels. The inclusion of titanium dioxide significantly enhances the mechanical and tribological performance of the calcium phosphate coatings, making them suitable for biomedical applications, especially in implants requiring long-term durability and enhanced compatibility. Full article

In this study, bentonite clay was modified through silane treatment and calcination to enhance its compatibility with basalt fiber (BF) and epoxy in multiscale composites. The as-received bentonite (ARB) was subjected to silane treatment using APTES, producing silane-modified bentonite (STB), while calcination yielded calcined bentonite (CB). The modified clays were incorporated into basalt fiber-reinforced epoxy (BFRP) composites, which were fabricated using the vacuum-assisted resin transfer method (VARTM). Analytical techniques, including X-ray diffraction (XRD) and Fourier-transform infrared (FTIR) spectroscopy, confirmed the structural changes in the clays. BET surface area analysis revealed a 314% increase in the surface area of STB and a 176% increase for CB. The modified clays also demonstrated reduced hydrophilicity and swelling behavior. Thermogravimetric analysis (TGA) indicated a minimal improvement in thermal stability, with the degradation onset temperatures increasing by less than 3 °C. However, tensile tests showed significant gains, with CB- and STB-reinforced composites achieving 48% and 21% higher tensile strength than ARB-reinforced composites. Tribological tests revealed substantial reductions in wear, with CB- and STB-reinforced composites showing 90% and 84% decreases in the wear volume, respectively. These findings highlight the potential of modified bentonite clays to improve the mechanical and wear properties of basalt fiber–epoxy composites. Full article