Antifriction Properties Research Articles

Multiplex Biomimetic SLIPS With Super-Lubricity to Multiphase Matters.

In recent years, slippery liquid infused porous surfaces (SLIPS) renowned for their exceptional liquid repellency and anti-fouling properties, have garnered considerable attention. However, the instability of both structural integrity and the oil film severely restricts their practical applications. This study is inspired by superwetting biological surfaces, such as fish scales, seashells, and Nepenthes, to design and fabricate a multiplex biomimetic and robust lubricant-infused textured surface (LITMS) using laser-coating composite processing technology. The influence of morphological structure and chemical composition on oil stability, wettability, and lubricating properties are systematically investigated. The LITMS exhibits remarkable repellency toward multiphase materials, including liquids, ice crystals, and solids, demonstrating exceptional omniphobicity, anti-icing, and anti-friction properties. Thus, this preparation strategy and construction methodology for SLIPS provide new insights into interfacial phenomena and promote advancements in applications for engineering material protection and machinery lubrication.

Use of Electrospun Cellulose Acetate/Silica Composites as Multifunctional Ingredients in Eco‐Friendly Semisolid Lubricant Formulations

ABSTRACTCellulose acetate/silica (CA/SIL) nanocomposites are prepared by electrospinning and investigated as multifunctional ingredients in eco‐friendly semisolid lubricant formulations. The structuring ability of these electrospun composites in castor oil and the antifriction and antiwear properties are examined through rheological and tribological experiments. The multifunctionality of CA/SIL composites arises from a balance between the silica content and the formation of nanofiber‐dominated structures. The linear viscoelasticity functions in the oleo‐dispersions increase by several orders of magnitude with both the spinning solution concentration and the CA:SIL ratio. However, the rheological response primarily depends on the morphology of the nanofiber mat obtained, specifically nanofiber diameter and the presence of beads. In contrast, the silica content significantly impacts the tribological performance of the oleo‐dispersions regardless of nanofiber morphology. For similar nanoarchitectures and rheological responses, the friction coefficient is reduced from 0.227 to 0.108 by incorporating silica in a 10:1 CA:SIL ratio, compared with the SIL‐free electrospun CA nanofibers, while wear is completely prevented. Increasing the composite concentration from 5 to 12.5 wt. % enhances wear protection and the gel strength of oleo‐dispersions, for example, the plateau modulus rises from 800 to 42,000 Pa using a composite with a 10:1 CA:SIL ratio.

Study on the Surface Texture-Microparticles Synergistic Lubrication Mechanism of Artificial Joint

Abstract After total joint replacement surgery, frequent injection of lubricating substances is required due to lubrication failure caused by the absorption of lubricants by the human body, which will cause serious physiological and psychological burdens on patients. In this study, with the help of surface texture aggregation of particles, gelatin microgel particles with a diameter of about 4 μm were used as lubricating substances to achieve aggregation in the texture, thus improving the friction environment under low-concentration lubricants. The study found that the rectangular cross-sectional texture demonstrated the most effective anti-friction properties, resulting in a 26% reduction in friction coefficient compared to non-textured surfaces. Additionally, utilizing comsol for particle flow simulation, researchers observed the motion behavior of particles within the texture and clarified the mechanism of particle aggregation and the improvement of lubrication on the surface. This article confirms the beneficial effects of combining surface texture and particles on lubrication, thus providing valuable insight for improving lubrication in dilute particle solutions.

Tribological Properties of 7A04 Aluminum Alloy Enhanced by Ceramic Coating

The 7A04 Al alloy is a commonly used lightweight metal material; however, its low wear resistance limits its application. In this study, the wear resistance of this alloy was improved by preparing micro-arc oxidation (MAO) coatings, MAO/MoS2 composite coatings, and hard-anodized (HA) coatings on its surface. The friction and wear behaviors of these three coatings with diamond-like coated (DLC) rings under oil lubrication conditions were investigated using a ring–block friction tester. The wear rates of the coatings on the block surfaces were determined using laser confocal microscopy, and the wear trajectories of the coatings were examined using scanning electron microscopy. The results indicated that, among the three coatings, the MAO/MoS2 coating had the lowest coefficient of friction of 0.059, whereas the HA coating had the lowest wear rate of 1.47 × 10−6 mm/Nm. The MAO/MoS2 coatings exhibited excellent antifriction properties compared to the other coatings, whereas the HA coatings exhibited excellent anti-wear properties. The porous structure of the MAO coatings stored lubricant and replenished the lubrication film under oil lubrication. Meanwhile, the introduced MoS2 enhanced the densification of the coating and functioned as a solid lubricant. The HA coating exhibited good wear resistance owing to the dense structure of the amorphous-phase aluminum oxide. The mechanisms of abrasive and adhesive wear of the coatings under oil lubrication conditions and the optimization of the tribological properties by the solid–liquid synergistic lubrication effect were investigated. This study provides an effective method for the surface modification of Al alloys with potential applications in the aerospace and automotive industries.

Tribological performance of TiO2 nanoparticle-oil-water emulsion in the hot rolling process

This study aims to evaluate the lubrication performance of a nano-TiO2 oil-in-water (O/W) emulsion during the hot rolling process. A series of O/W emulsions with varying concentrations of TiO2 nanoparticles (0.05, 0.1, 0.3, and 0.5 wt.%) were synthesized. Tribological tests were conducted under a load of 70 N for 10 minutes to determine the optimal concentration based on anti-frictional properties. The O/W nano-emulsion optimized with a 0.1 wt.% concentration of TiO2 applied in the hot rolling process of IS 2062 E250 grade steel. This application resulted in a reduction of rolling force (RF) and surface roughness, suggesting its potential as an alternative lubricant. The results indicated superior antifriction performance at a TiO2 concentration of 0.1 wt.%, leading to a 15% reduction in RF. Additionally, the use of the nano-emulsion contributed to a significant reduction in oxide scale formation. Surface roughness measurements of the rolled samples revealed a 19% decrease, with a roughness value of 2.125 µm, compared to samples rolled with a nano-free O/W emulsion. These findings suggest that nano-TiO2 O/W emulsions could serve as an effective alternative to conventional O/W emulsions in future industrial metalworking applications.

Tribological performance of the micro-textured ceramic/superalloy interface under nanofluid minimum quantity lubrication considering electroosmotic effect

To achieve “sustainable and eco-friendly machining processes”, the micro-groove textures were fabricated on the Si3N4 ceramic surfaces for enhancing the penetration ability of nanofluids into friction interface under the electroosmotic effect. The rotating sliding friction experiments were performed against Inconel 718 superalloy balls on a ball-on-disk tribometer under 20 °C and 220 °C to evaluate the high temperature tribological properties of Si3N4 ceramics with the lubrications of Fe3O4 and SiO2 nanofluids. Results indicate that the Si3N4 samples exhibit the best wear morphology, achieving the lowest friction coefficient and wear volume with SiO2 nanofluid at a concentration of 0.5 vol% regardless of 20 °C or 220 °C, with values of 0.35/0.42 and 5.3/6.0 × 10−2 mm3. The superior electroosmotic performance of SiO2 nanofluid contributes to its remarkable penetrability and compatibility with Si3N4 ceramics. Therefore, utilizing the electroosmotic effect of nanofluid, which is induced by the self-excited electric field at the friction interface and further incorporating the electroosmotic force, effectively enhances the infiltration capability of nanofluid. This enhancement facilitates efficient cooling and lubrication of ceramic/superalloy interfaces, thereby improving anti-friction and anti-wear properties.

Thermobarrier and antifriction properties of triboceramics on the surface of a cutting tool with (TiAlCrSiY)N/(TiAlCr)N coating during high-speed dry cutting

Thermobarrier and antifriction properties of triboceramics on the surface of a cutting tool with (TiAlCrSiY)N/(TiAlCr)N coating during high-speed dry cutting

Using Thin Ultra-High-Molecular-Weight Polyethylene Coatings to Reduce Friction in Frost-Resistant Rubbers.

Frost-resistant rubbers retain their highly elastic properties over a wide temperature range. They are used in various friction units (e.g., seals), but their high friction coefficient and low wear resistance lead to the need for frequent replacement. In this paper, we propose applying thin (several hundred microns) UHMWPE coatings to formed rubber rings. The application technology depends on the required coating thickness. Friction tests of the coatings and pure UHMWPE were performed using the ball-on-disk (unidirectional sliding) scheme for various loads and velocities. In the experiments, the friction coefficients and temperatures near the contact area were determined. Friction tracks were studied using microscopy methods. The sliding contact of the ball and the two-layer material was modeled to obtain the dependences of the deformation component of friction on the sliding velocity for coatings of different thicknesses. UHMWPE is sensitive to frictional heating, so the thermal problem of determining the temperature in the contact area was also solved. It is shown that the minimum friction coefficient occurs for coatings with a thickness of 600 μm. At the same time, in the case of the 300 μm coating, the surface of the friction track is practically no different from the initial one. Thus, the studied combination of polymers provides antifrictional properties and wear resistance to the surface layer while maintaining the damping properties of rubber.

Synthesis and Performance Evaluation of Metallocene Polyalphaolefins (mPAO) Base Oil with Anti-Friction and Anti-Wear Properties

Anti-wear and anti-oxidation abilities are two key properties of lubricants that play a crucial role in ensuring long-term stable equipment operation. In this study, we aimed to develop a base oil with good anti-oxidation and anti-wear properties for use under extreme pressure. The as-prepared metallocene polyalphaolefin (mPAO) was chemically modified using the trifluoromethanesulfonic acid (TfOH) catalysis through an alkylating reaction with triphenyl phosphorothioate (TPPT). During the experiments, when the reaction temperature exceeded 70 °C or the concentration of TfOH exceeded 2.67%, the β-scission reaction in the alkylation process became significantly more pronounced. The physical and chemical properties of TPPT-modified mPAO (T-mPAO) were evaluated by nuclear magnetic resonance spectroscopy, Fourier trans-form infrared spectroscopy, gel–permeation chromatography, and ASTM standards. T-mPAO showed significantly improved antioxidant capacity, with the initial oxidation temperature increasing by 32 °C compared to the base oil, and it exhibited the slowest increase in acid number in the 96-h oven oxidation test. The tribological tests showed that T-mPAO had the lowest friction coefficient, wear track, and wear rate (72.7% lower than that of mPAO) as well as the highest PB (238 kg) and PD (250 kg) among all tested samples. Compared to mPAO, the average friction coefficient of TPPT-modified mPAO in the four-ball friction test was reduced by 30.5%, and by 16.4% in the TE77 reciprocating friction test. Based on the experimental results, T-mPAO had strong anti-oxidation ability and excellent lubricating performance.The successful synthesis of multifunctional mPAO has enabled lubricant base oil additization, making it possible to use it in more demanding work scenarios, greatly broadening its application scope and making lubricant formulation blending more flexible.

Tribological properties of a smart Ti3C2Tx-based epoxy coating: Providing an idea to solve the weak tribological properties of traditional smart coatings

Friction damage is always a major threat to the wide application of smart anticorrosion coatings. Here, the tribological properties of a smart Ti3C2Tx-based epoxy coating (MLT@EP) is adjusted by the reasonable collocation of mesoporous silica nanocapsules loading onto Ti3C2Tx-based plane (MLT). MLT@EP not only maintains good smart anticorrosion, but also has remarkable anti-friction and anti-wear properties. Its friction coefficient exhibits a low and steady trend, and the wear rate arrived at 1.14 × 10−5 mm3/N·m, which is decreased by 58.3 ∼ 93.3 % compared to control groups. The excellent tribological properties are mainly attributed to the synergistic effect of MXene-based lubrication film, high resistance to plastic deformation, and strong internal interaction.

Tribological properties of the P and S-free protic ionic liquids as water-based lubricants

Three kinds of P and S-free 1,8-Diazabicyclo[5.4.0] undec-7-ene water-soluble protic ionic liquids (PILs) were successfully synthesized and applied as additives in water-1,2-Propylene glycol (PG). The physicochemical properties of PILs and the anti-friction, anti-wear and anti-corrosion properties were investigated. Research results demonstrated that the addition PILs lubricant additive could greatly improve the tribological properties of water-1,2-PG. The addition of 5 wt% PILs with long alkyl chain will result in the reduction of friction coefficient and wear volume by about 45 % and 95 %, respectively. Meanwhile, the PILs with long-chain show more effect lubrication behavior than the short one. In addition, the obtained PILs also possess excellent anti-corrosion properties as water-based lubrication additives. The elemental analysis of the contact area showed that the PILs would generate a chemical reaction film during the friction process, and the carboxylate anion could form a chemical and physical adsorption film on the surface of contact area, which would provide better anti-friction and anti-wear properties.

Influence of deep-sea hydrostatic pressure on the tribocorrosion behavior and mechanism of La2O3–TiB2–Ni coating

To understand the tribocorrosion mechanism of TiB2–Ni coating doped with La2O3 in the deep ocean, the wear and corrosion test of La2O3–TiB2–Ni under various hydrostatic pressures was conducted and discussed in 3.5 wt % NaCl solution. The results indicate that the tribocorrosion mechanism of the La2O3–TiB2–Ni coating transitions from abrasive wear with corrosion under 0.1 MPa to abrasive wear with corrosion and adhesive wear under high hydrostatic pressure. The La2O3–TiB2–Ni coating shows significant enhancements in wear resistance and anti-friction properties compared to the TiB2–Ni coating. As the hydrostatic pressure increases from 0.1 MPa to 30 MPa, the self-corrosion current density experiences an approximate increase of 43.6 μA/cm2.

Investigation of sliding wear, electrochemical corrosion, and biocompatibility of Ti-Nb alloys for biomedical applications

This research emphasizes the development of biocompatible Ti-xNb (0, 5, 10, 15, 20, and 25 wt.%) alloys through powder metallurgy to attain a lower elastic modulus, high strength, low wear, and high corrosion resistance appropriate for biomedical implants. The developed alloys were comprehensively analyzed through microstructural, physical, mechanical, electrochemical, biological, and tribological investigations to assess their suitability by comparing their properties with commercially pure titanium (cpTi). The outcomes demonstrate, powder metallurgy is an effective route for developing Ti-Nb alloys with several desirable properties. Incorporating niobium (Nb) into titanium (Ti) introduces the β phase within the alloys, which increases with Nb concentration and contributes to decreasing the elastic modulus to as low as 43.47 ± 4.9 GPa. All Ti-Nb alloys exhibits higher hardness and compressive strength than cpTi, with values of 403.23 ± 21.38 HV and 1322.45 ± 25.64 MPa obtained for the Ti-10Nb alloy. A lower concentration of Nb shows comparable corrosion resistance of the Ti-Nb alloys to cpTi, whereas a higher Nb concentration is unfavorable. Furthermore, the tribological findings demonstrate superior antifriction and antiwear properties in all Ti-Nb alloys compared to cpTi. Notably, Ti-10Nb displays outstanding wear resistance with a 41.82% lower friction coefficient in dry conditions and 31.11% in simulated body fluid (SBF), along with 81.08% reduction in wear volume in dry conditions and 63.11% in SBF compared to cpTi. Among all developed alloys, Ti-10Nb exhibits various desired properties, suggesting its potential as an alternative to cpTi for biomedical implant applications.

Epoxy composite materials filled with rice husk ash

The present research responds to two current tendencies, such as circular economy, involving reuse of industrial waste, and green chemistry, presupposing application of renewable resources and technologies, which minimize the negative environmental impact. The present article is dedicated to the study of the application of rice husk and its ash as a filled for epoxy composite materials. Rice husk represents a multi-tonnage agricultural by-product, subject to recycling, and at the same time, is a valuable source of amorphous silica. Temperature regime of rice husk ash (RHA) production, optimum content and particle size of filler providing maximum modifying effect were determined. The influence of modifying fillers on the complex of operational properties of filled epoxy compositions including hardness, wear resistance, adhesion to steel and aluminium and antifriction properties of epoxy coatings has been established. A comparative analysis of the properties of modified compositions with non-filled ones and with compositions filled with fully amorphous silica, including industrial analogue Aerosil 300, has been carried out. It has been established that the best compatibility with polymer epoxy matrix is possessed by rice husk ash obtained at the combustion temperature of 500оC introduced in the amount of 10 mass parts per 100 mass parts of epoxy polymer.

Effect of Cu content on the microstructure and properties of sintered Fe-0.8C-xCu antifriction materials

Abstract Ferrous antifriction materials (FAMs) play a crucial role in powder metallurgy. Previous studies have primarily focused on exploring the antifriction properties of Fe-C-Cu materials with low copper content (0–5 wt%), while there have been fewer studies on high copper content FAMs. In this study, to investigate the effect of Cu content on the microstructure and properties of sintered FAMs, Fe-0.8C-xCu (x = 5–25 wt%) materials were prepared by powder metallurgy method. The density, microstructure, mechanical performance, friction and wear properties of the samples were analyzed. The results demonstrated a significant change in the relative density, hardness, friction and wear properties of sintered Fe-0.8C-xCu samples with increasing Cu content. Particularly, the Fe-0.8C-15Cu samples exhibited outstanding properties, with a relative density of 77.8%, a hardness of 43 HRB, crushing strength of 380 MPa, an average friction coefficient of 0.21, and a wear rate of 1.36 × 10−8 mm3 N·mm−1. The primary wear mechanisms of the Fe-0.8C-xCu specimens include abrasive wear, adhesion wear, chafing fatigue, pitting, and oxidation. This study aims to provide an experimental and theoretical basis for the development of ferrous antifriction materials suitable for heavy-load conditions.

Synthesis of bio-based nanolubricant using bimetallic nanoparticles to mitigate the surface deterioration of low carbon steel for metalforming industry

Worldwide industries are drawing their attention to the usage of bio-based substances for their operational purposes. Herein, the bimetallic nanoparticles (Bi-MNPs) were synthesised using a unique combination of Zn–Cr in bio-based mustard oil by green route utilizing wet chemical approach. Synthesised Bi-MNPs (0.12–0.15 wt%) were employed in the synthesis of bimetallic bio-based nanolubricant (Bi-BNL), and the impact was also evaluated on low carbon steel (grade SAE1006). The reduction of Bi-MNPs was carried out by green reducing agents and their stabilisation was confirmed by Fourier transform infrared spectroscopy (FTIR). Whereas, the synthesis of Bi-MNPs was followed by Surface plasma resonance (SPR), average size of Bi-MNPs which was about 60 nm and morphology was established using Scanning electron microscopy (SEM). The efficiency of Bi-BNL and impact of Bi-MNPs on the stability of Bi-BNL was investigated by Dynamic light scattering (DLS), Zeta potential (ZP) and comparative study was carried out with reference lubricant. Interestingly, the kinematic viscosity (KV) values of the lubricants are quite compatible, and have linear relationsip with coefficient of friction which is very suitable to conclude the anti-friction and anti-wearing properties. The KV of bio-based oil was monitored under the criteria of standard test method ASTM D445, and the resultant value was compared with the reference oil. The stability of Bi-BNL and its interaction with low carbon metal sheet was also studied; the outcomes were very impressive due to no rust patches, oil spots and surface deterioration on the metal sheet. The paramount creativity of this research work is the modification of bio-based oil via Bi-MNPs for the synthesis of Bi-BNL that offers the best surface quality of low-carbon steel. Cumulatively, these findings of Bi-BNL could be open up new possibilities to explore the bio-based synthesis of lubricants on a comprehensive scale.

Fabrication and assessment of dry sliding behavior of Ti3C2Tx-MXene reinforced nickel aluminide composites

MXene has been recognized globally for its ability to act as a solid lubricant, lubricant additive, and protective coating for enhancing the performance and longevity of dynamics systems. Ni3Al matrix composites have been fabricated through spark plasma sintering with varying Ti3C2Tx-MXene concentrations and slid against the Si3N4 ball to evaluate the lubrication potential at atmospheric conditions. The addition of MXene in the matrix has improved anti-friction and anti-wear properties attributed to the formation of a tribo-layer on encountering surfaces consisting of oxides and MXene’s fragments, as confirmed by TEM and Raman spectroscopy. However, further increasing MXene to 20 % led to an increase in friction, ascribed to the dominance of the hard TiC phase, which acts as a barrier for tribo-layer formation.

High Temperature Induced Low Friction and Wear in a-C:Si via Formation of a "H Passivation Layer/a-SiO2/H Passivation Layer" Structure in a Humid Environment.

Doping Si into amorphous carbon can decrease humidity sensitivity, improve thermal stability, and retain excellent friction performance. Experimental studies have shown that Si-doped amorphous carbon formed Si-OH structures and frictional oxides in high-temperature and humid environments. However, the formation process of Si-OH and frictional oxides, as well as their structure, formation conditions, and antifriction properties, remains unclear. In this paper, reactive force field molecular dynamics (ReaxFF MD) was used to investigate the frictional performance of a-C and a-C:Si (7.2 atom %) at temperatures of 300, 700, and 1500 K in H2O environments. The results showed that with increasing temperature, the friction force of a-C increases from 8.2 nN at 300 K to 15.51 nN at 1500 K, while that of a-C:Si decreases from 10.3 nN at 300 K to 5.6 nN at 1500 K. In H2O environments, a-C:Si formed a "H passivation layer/a-SiO2/H passivation layer" structure, which inhibited the formation of interfacial bonds between the upper and lower substrates and reduced the wear of the substrate while ensuring the antifriction and antiwear properties of a-SiO2. This paper reveals the mechanism behind the low friction characteristics of a-C:Si in high-temperature and humid environments, providing theoretical guidance for the application of a-C:Si under such conditions.

A novel antibacterial and wear-resistant strategy based on metal surface micro-texture nitriding coupled functional mesoporous silicon coating

Modified metal layers coupling durable antifouling and antibacterial properties have garnered considerable interest in various fields, including but not limited to medical equipment, kitchen utensils, public facilities, and specific industrial applications, such as transportation, energy utilization, and aerospace. Nevertheless, wear and corrosion resulting from harsh operating environments can significantly compromise the modified metal layers, leading to diminished antifouling and antibacterial capabilities. Currently, maintaining excellent antibacterial properties on the surface of metal-modified layers under complex working conditions remains a key challenge for metal protection technology. Herein, we innovatively propose a ternary collaborative strategy to optimize and extend the antifouling and antibacterial activity of metal substrate surfaces. Firstly, laser surface texturing (LST) is used to create micro-textured topography on the metal surface to serve as a reservoir for collecting debris and storing functionalized nanoparticles. Then, the surface micro-textures are treated with plasma nitriding to form a wear-resistant passivation layer that protects the aforementioned microstructures. Finally, a lubricant containing functional mesoporous silicon nanoparticles (Ag2O-MSNs@OTES) is coated on the metal surface, which not only reduces the friction coefficient but also achieves antibacterial and antifouling effects by continuously releasing silver ions from the mesoporous silicon spheres. Employing the aforementioned ternary coordination strategy, the fabricated coupling layer exhibits not only exceptional antifriction and wear properties but also remarkable antibacterial efficacy against both E. coli and S. aureus, attributed to the Ag2O-MSNs@OTES. Therefore, the wear-resisting and antibacterial coupling layer for the protection of metal surfaces has promising and versatile applications in wide areas.

Tribological behaviour of laser textured Ti3AlV 2.5V alloy under simulated body fluid

The use of lasers to fabricate micro-textures on the surface of medical implants is an effective method to improve their bio-tribological properties. In the present study, three distinct configurations of micro-textures, namely, co-axial circles, hexagon, and line with varying spacing of 300 µm, 400 µm, and 500 µm, were fabricated on Ti3Al2.5V alloy using Nd:YAG fibre lasers. The influence of micro-textured geometries on microhardness, coefficient of friction (COF), and wear rate was estimated. The tribological properties of the polished and textured samples were investigated using a linear reciprocating tribometer against silicon nitride (Si3N4) balls under simulated body fluid (SBF) lubricant. Orthogonal results indicate that the co-axial circles with a spacing of 305 µm prove to be the most efficient in enhancing the tribological performance of textured surfaces. This configuration demonstrates a significant improvement, with a 33.62 % reduction in friction coefficient and a 61.81 % reduction in wear rate compared to polished samples. The decrease in spacing appears to enhance the anti-friction and anti-wear properties of the textured surfaces. The working mechanism behind the reduction in the friction coefficient and wear rate lies in the capacity of the textures to trap particles.