Search

In this article, lentils are used as a case study to characterise the particulate behaviour of soft granular materials. Experiments were carried out on a single lentil particle or a pair of lentils. The single particle or a pair of particles in contact were compressed vertically to crushing or to a fixed vertical load. Then, in inter-particle tests, pairs of particles were slid over each other at a constant vertical load, and the tangential stiffness and coefficient of friction were estimated. The pairs of lentil particles in contact were also subjected to repeated normal and tangential loading. The presence or absence of the cover of lentil particles (shell) was found to affect their behaviour significantly under these loading conditions. The lentil particles have a very compliant shell and stiff core in normal loading; the stiffness of the shell is constant, and the core follows Hertz contact law. The lentil particles show less variability in their crushing strength, with high Weibull modulus (~ 10), in comparison to other natural granular materials like sand. With repeated cycles of vertical loading, the contact between a lentil pairs of particles becomes more stiff and less damp. In tangential loading, the coefficient of friction between lentil particles decreases with normal force while the contact stiffness increases. Further, in cyclic tangential loading, the coefficient of friction decreases and the contact stiffness increases with cycles. A simple contact model is also proposed to use in discrete element simulations. [ABSTRACT FROM AUTHOR]

The orientation effect of chopped tiny steel fibres (length < 3 mm; diameter < 200 µm) in brake pads parallel (NAPA) to the sliding direction is studied using two different methods. Inverting the specimen during testing yields fibre perpendicular (NAPE) to the sliding direction, which is compared to commercial random-oriented fibre pads (NARA). The orientation coefficient value of near unity is achieved only in NAPA. NAPA and NAPE have a lower density than NARA by 13.2% due to less than 54.55% of steel fibres in the formulation. More and larger plateaus stabilized friction in NARA, utilising the elongation properties of parallel steel fibres, than in NAPE, which produced only tiny plateaus. However, the wear resistance decreases when the sliding path or direction changes from parallel to perpendicular. The measurement of thickness loss is misleading during wear because of the swelling effect, and hence energy requirements are considered. The energy required to wear 1 cc of specimen in the NAPE is 23.78% greater than that in the NAPA, and hence wear resistance is better. Adhesion followed by delamination at elevated temperatures are the dominant wear mechanisms in NAPA, whereas abrasion is dominant in NAPE. Thus, semi-metallic performance can be obtained in a very low metallic pad by orienting these fibres. [ABSTRACT FROM AUTHOR]

The frictional performance of water-lubricated UHMWPE is influenced by the combination of structural parameters and operating conditions. To improve the efficiency of optimal design of surface texture aimed at improving frictional performance, a novel integration of the Orthogonal Array method (OAM), machine learning (ML) prediction, and Particle Swarm Optimization (PSO) is proposed for predicting and optimizing the coefficient of friction (COF) of copper ball-textured UHMWPE surfaces using a small dataset. In order to reduce manufacturing and testing cost, decrease required training samples for ML algorithm, OAM which could efficiently acquire data set with comprehensive feature information is used to determine the parameters of test samples to generate a small but effective dataset. 25 textured samples based on L16 (44) and L9 (34) are fabricated, with the parameter set determined using OAM. COFs of the samples are tested using RTEC tribo-tester. Trend analysis is conducted to investigate the influence of force, frequency, depth and ellipse axis ratio on COF. Multi-linear Regression (MLR) and Gaussian Process Regression are employed. MLR exhibits better prediction accuracy and is integrated with PSO to minimize COF. The error between the experimental and the theoretical results obtained by the integration method of MLR and PSO is only 1.04%, demonstrating the feasibility of predicting COF and optimizing surface texture using the integrated method with a limited dataset determined by OAM. [ABSTRACT FROM AUTHOR]

In sugarcane cultivation, operations from sowing to harvesting are critical and time-consuming. The lack of manual labor poses risks and increases drudgery, necessitating mechanization based on the engineering properties of 10–12 month old sugarcane stalks. Engineering properties of three sugarcane varieties (CoLk 14201, CoLk 09204 and CoPk 05191) from IISR Lucknow were evaluated. These properties are essential for designing effective machinery components. The average sugarcane stalk length and weight across three varieties were 2096 mm and 1.03 kg, with average diameter of 23.48 mm (bottom), 25.38 mm (middle) and 24.13 mm (top). Three-budded setts were longest and heaviest, followed by two-budded setts, with single-budded setts being the smallest and lightest. Setts length ranged from 55 to 354.5 mm, weight from 28.37 to 207.38 g and diameter from 15 to 29 mm. Optimal moisture content for setts was 70–75%, with values ranging from 67.57 to 83.33%. Bulk density varied between random and aligned storage, from 0.231 to 0.491 g/cm3 and 0.348 to 0.597 g/cm3, respectively. Coefficients of friction were highest with rubber and lowest with FRP. CoLk 09204 had the highest friction across all setts, while CoPk 05191 had the lowest, with vertical orientations showing higher friction. Penetration resistance increased from top to bottom internode segments, with CoLk 09204 showing the highest resistance (8.02–9.88 N/mm2). Cutting resistance was highest at the bottom stalk position, with CoLk 09204 having the greatest resistance (3.5 N/mm2). Crushing resistance was significantly higher in CoLk 09204 (1742–1787 N) and it also exhibited the highest bending resistance (1414.06 N/mm2), indicating a denser, more resistant stalk structure. These findings are essential for optimizing various sugarcane cultivation machinery components and processing methods. [ABSTRACT FROM AUTHOR]

Ejection is the most critical phase in the injection moulding process and depends on several variables that can affect and difficult the demoulding process. Some phenomena in the mould, such as shrinkage, adhesion and friction, can lead to higher ejection forces. Friction, deformation and adhesion mechanisms are components of the coefficient of friction that occurs between the mould and the part surface. An increase in the coefficient of friction will result in higher ejection forces and consequently increase the energy consumption during the demoulding process. Mould and part material, mould surface roughness, coatings and ejection temperature are some of the variables that can affect the coefficient of friction in the injection moulding process. This review paper presents some considerations on the mechanisms, the process and material variables that can affect the coefficient of friction. [ABSTRACT FROM AUTHOR]

Slip and fall accidents are common both indoors and outdoors, posing and risks from minor to serious injuries. An effective way to prevent these accidents is for pedestrians to know the friction properties of their path beforehand. Developing a network that can discern the frictional properties of surfaces from camera-captured images and convey this information to pedestrians could significantly reduce the incidence of slips. However, predicting the indoor friction coefficient of tiles accurately is challenging due to reflections from multiple fluorescent lights and the tiles themselves. Additionally, water accumulation on tiles due to cleaning or leakage greatly contributes to slip accidents. This paper presents an algorithm that accurately predicts floor friction coefficients in real indoor environments, accounting for image distortions caused by light reflections and water on the floor. Experimental results validate that the proposed system reliably predicts indoor floor friction coefficients despite factors such as lighting angles and water presence. Moreover, to demonstrate its practical applicability, a user-application has been developed to predict the friction coefficient for specific areas as required. This system can be integrated into various devices, including walkers, canes, and smartphones, to assist pedestrians in navigating safely. [ABSTRACT FROM AUTHOR]

The tribological behavior of silicon nitride (Si3N4) ceramic with textured patterns under water lubrication was investigated in this paper. Different textured patterns were fabricated using laser surface texturing (LST). Surface wettability was characterized by contact angle. The original surface and textured Si3N4 ceramic with triangular patterns presented as hydrophobic. However, the textured Si3N4 ceramic with hexagonal patterns presented as hydrophilic. Surface wettability and textured patterns were important factors affecting the friction performance of the Si3N4 ceramic. Our results indicated that symmetrical textured patterns were more beneficial for decreasing the coefficient of friction (COF) at lower reciprocating frequencies. In contrast, better surface wettability played a more important role in reducing the COF at higher reciprocating frequencies. The most severe damage observed on the untextured Si3N4 ceramic led to a higher wear rate. The symmetrical structure of hexagonal patterns was more conducive to decreasing the wear rate than triangular patterns. However, the Si3N4 ceramic with triangular patterns was more suitable for use at high-speed frictions due to better lubrication. The textured patterns had the function of storing lubricants and capturing and cutting debris. Thus, friction performance was improved by introducing textured patterns onto the surface of the Si3N4 ceramic. The friction and wear mechanisms are also discussed in this study. [ABSTRACT FROM AUTHOR]

Nitriding is a well-known thermochemical treatment improving the surface hardness and the wear resistance of steel. The phase composition and growth kinetics of the nitrided layer can be controlled using a gas nitriding with changeable nitriding potential. In this work, such a gas nitriding was used to produce, on 42CrMo4 steel, the two nitrided layers differing in the thickness of compound zone and diffusion zone. The microstructure and nanohardness of these layers were studied. For the first time, the tribological behavior of gas nitrided layers at elevated temperatures (from 23 to 400 °C) was investigated. The compound zone consisted of ε + (ε + γ') iron nitrides and, in the diffusion zone, the nitric sorbite with γ' precipitates was observed. The highest nanohardness was measured in the ε + γ' zone. The lowest values of friction coefficients were obtained if the contact surface of the friction pair entered the ε + γ' zone. After the wear process, at a final temperature of 400 °C, worn surfaces showed only intensive abrasive wear, evidenced by shallow grooves. The increased oxygen content at the edges of wear tracks indicated possible oxidative wear. [ABSTRACT FROM AUTHOR]

Yttria-stabilized zirconia and flake graphite c omposite (C/YSZ) coatings were successfully prepared on a TC4 substrate by electrophoretic co-deposition and sintering at 1100 °C using YSZ nanopowder and flake graphite. The effects of the graphite content on the microstructure and friction-wear properties were investigated. The results indicated that flake graphite agglomerated in the C/YSZ coating. The YSZ coating with 0.6wt.% graphite exhibited the highest toughness with the plastic resistance index (H/E) of 0.0172, which was 6.8 % higher than that of the YSZ coating, and effectively inhibited the formation of coating cracks. However, an increase or a decrease in the graphite content led to a decrease in the toughness of the C/YSZ composite coating. The agglomerated graphite in the C/YSZ composite coating acted as a solid lubricant and affected friction and wear properties. The coefficient of friction (COF) of the 0.6C/YSZ sample was 0.45, which was 40 % lower than that of the YSZ sample. The reason for this was that graphite effectively inhibited the falling-off of debris from the coating surface and reduced abrasive wear. However, an excessive amount of graphite, i.e., in case of the 0.8C/YSZ coating, decreased the roughness of the wear surface, leading to a reduction in the H/E and COF by 24.4 % and 29.7 %, respectively. [ABSTRACT FROM AUTHOR]

Recently, lightweight nanocomposite materials were mostly preferred in automobile sliding parts such as bushes, clutch plates, piston pins, brake shoes, bearing races, and cylinder liners subjected to tribological failures plays a vital role. This study aims to investigate the impact of utilizing Multi-walled carbon nanotubes (MWCNTs) and Silicon dioxide (SiO2) in equal proportions, with weight content variations of 0%, 1%, and 2%, in a polymer reinforced with natural basalt and synthetic glass fibers. The investigation will be conducted using a pin-on-disc wear test apparatus under dry sliding conditions, following ASTM standards. Three nanocomposite laminates were fabricated by manual layup method through the ultrasonication and magnetic stirring process Box-Benkhen Design (BBD) is employed to design experiments involving four input variables: filler content, load applied, distance of sliding, and velocity of sliding. The Response Surface Methodology (RSM) technique was employed to analyze the tribological properties. The study employed the Analysis of Variance (ANOVA) technique to identify the primary factors and construct regression mathematical models for output responses. The results showed that the minimum friction coefficient and specific wear values were 0.159 and 0.0002 mm3/Nm, respectively, when employing a 1% filler weight, load applied 20 N, distance sliding 1000 m, and velocity of sliding 1 m/s. The minimum filler content, friction coefficient, and specific wear rates exerted the greatest influence followed by other factors. [ABSTRACT FROM AUTHOR]

Aluminium-carbon nanotube (Al-CNT) composites have proven to offer a lot of potential for applications involving friction and wear. This study investigated the wear behaviour of Al-CNT composites with uniformly dispersed CNTs without structural damage at concentrations of 0.5 wt%. The wear behaviour of these composites has been compared with that of pure aluminium, which was fabricated using the identical wet shake mixing, compaction, and extrusion procedure. The study aimed to determine how CNT concentration and applied stress influence the wear behaviour of composite materials. Scanning electron microscope (SEM) was used by the researchers to examine the surface features of the worn samples. The study showed a significant increase in hardness and wear resistance with adding CNT. Compared to pure aluminium, the composite containing 0.5 wt. % CNTs demonstrated a 25% reduction in wear rate, and the average value of the coefficient of friction (µ) also decreased. The wear rate and coefficient of friction increased when samples containing 0.5 wt. % CNTs were subjected to various loading scenarios. The major contribution of CNTs to improving wear characteristics was discovered through SEM investigation of these worn surfaces. Using the ANSYS Workbench, a built finite element model was used to perform contact analysis on the disc and pin. Analytical results and experimental data were contrasted, and the ANSYS data was utilised to assess the process parameters. The comparison confirmed the analysis accuracy and dependability, which showed a consistent agreement between the analytical findings and the experimental results. [ABSTRACT FROM AUTHOR]

Exploring ways to improve the performance of rotating bands is of great importance for enhancing the power of modern artillery. This study prepared graphene oxide-coated Nylon (GO-Nylon) and Nylon samples based on nylon rotating bands in artillery systems to investigate the feasibility of introducing GO-coated nylon rotating band materials to enhance their tribological and thermal properties. The friction behavior and thermal effects of these two surfaces were analyzed under different external loads and surface roughness conditions. The results show that the excellent thermal conductivity of GO effectively reduced temperature accumulation during friction. Under an external load of 8 N, the surface temperature of GO-Nylon decreased by 14% compared to the Nylon surface, and the coefficient of friction (COF) decreased by 21%. At the same time, a simulation model was established, and its calculation results were consistent with the experimental trends, providing a further explanation of the experimental phenomena. This research provides a basis for the application of graphene-based coatings in the defense industry and presents new ideas for the development of high-performance rotating band materials. [ABSTRACT FROM AUTHOR]

Understanding the contact behaviour of slewing-ring thrust ball bearings is essential for accurate predictions of load distribution and evaluations of static and dynamic load capacity. Applying Hertz's theory to non-standard slewing ring bearings presents unique challenges due to their complex geometries and difficulties in achieving uniform surface finishes, leading to significant deviations from actual stress. This study addresses these limitations by comparing experimental results, numerical results, and the Hertz theory. The analysis considers three Hertz contact configurations between the bearing ball and the raceway. The results reveal significant deviations from the experimental values. To determine the cause of these variations, the friction coefficient between the ball and the raceway is determined using the gravitational method by varying the number of balls. Uneven load distribution across balls in slewing ring bearings under mechanical loads is exposed by friction coefficient measurement. To further explore, load-deformation experiments are conducted on the LMMB by placing varying numbers of balls and their positions. Results expose variations in load-taking behaviour among the balls, emphasizing the critical influence of contact area load distribution. [ABSTRACT FROM AUTHOR]

The objective of this work is to study the effects of Fe additions on the phase evolution, microstructure, and mechanical properties of heat-treated Ni(50-X)Ti50FeX shape memory alloys. The NiTiFe specimens were prepared by mechanical alloying, compaction, sintering, and heat treatment processes. The microstructural and phase analysis of the sample shows the NiTiFe phase along with Ti-rich and Ni-rich phases. Better mechanical properties were observed in 4 at.% Fe samples owing to the presence of secondary intermetallic phases such as Ti2Ni, Ni3Ti, Fe3Ti, and Ni4Ti3 compared to other samples. The 10 at.% Fe samples containing a higher percentage of NiTi(B19') and FeTi phases showed better shape memory behavior while showing a higher coefficient of friction as compared to other samples. Wear tests were done to determine the wear mechanisms prevalent during the tests. It was found that the adhesive and the abrasive wear were the most common mechanisms that contributed to the wear behavior of the sample. [ABSTRACT FROM AUTHOR]

The purpose of this investigation is to see how varying percentages of Graphene Nanoplatelets (GNP) affect the wear behaviour of carbon fibre reinforced epoxy (CFRE) composite. The hybrid nano composites were developed using hand layup process followed by compression moulding. Furthermore, the impact of operational parameters such as load and abrading distance against SiC paper of 220 grit size at a rotational speed of 200 rpm was investigated. It was found that incorporating a considerable amount (up to 0.5 wt. %) of GNP significantly improved the wear performance of CFRE composites. There is increase in wear loss again for 0.75 and 1.0 wt. % GNP. The morphology of developed nano hybrid composites were linked to data patterns on wear volume and specific wear rates. GNP addition up to 0.5 wt. % strengthened the fibre-matrix interface, preventing simple fibre pull-out from matrix/fillers and enabling increased wear resistance, according to worn surface characteristics investigation. [ABSTRACT FROM AUTHOR]

A comparative study of the temperature stability of a full-formula motor oil, Mobil Ultra SAE 10W-40, doped with two carbon nanoadditives (nanotubes and fullerenes) is presented. The optimum concentrations of the compared nanoadditives in terms of friction coefficients, as well as the optimum concentrations in terms of the amount of heat released during friction, have been preliminarily established. It was found that doping the studied oil with fullerene increases the critical temperature by 10–15°C, and alloying this oil with carbon nanotubes increases the critical temperature by 20–25°C. [ABSTRACT FROM AUTHOR]

This research investigated the tribological performance of phosphonium-based ionic liquid Tri hexyl tetra decyl-phosphonium bis (2, 4, 4-trimethylpentyl) phosphinate (IL) when used as an additive at a concentration of 1wt% to Cotton seed oil (CSO), Rattan Jot oil (RJO), Waste Cooking oil (WCO) and Polyalphaolefin (PAO) at different operating conditions. The results were compared with conventional PAO base oil. The tribological performance of all lubricants was studied using a Vertical Universal Testing Machine (MMW1A) and wear scar diameter were measured using an electronic microscope OLYMPUS DX-1000. The results indicated that the addition of ionic liquid further enhanced the tribological performance in terms of wear for all bio-lubricants except for waste cooking oil. However, the addition of ionic liquid does not have much effect on the tribological performance of PAO. Rattan Jot oil was found to have the best tribological properties with the addition of ionic liquid.

Abstract We used a neuromusculoskeletal model of bipedal walking to examine the effects of foot–ground friction conditions and gait patterns on slip- and trip-induced falls. We developed three two-dimensional neuro-musculoskeletal models in a self-organized manner representing young adults, elderly non-fallers, and elderly fallers. We simulated walking under different foot-ground friction conditions. The static friction coefficient between the foot and the ground was varied from 0.05 to 2.0. Under low friction conditions, the three gait models demonstrated slip-induced falls. The elderly faller model experienced the most slip. This is because the RCOF was higher in the elderly faller model due to its short stride length but much smaller foot clearance. Under high friction conditions, only the elderly faller model demonstrated trip-induced falls. Based on the analysis using the margin of stability, the forward postural stability of the model gradually decreased under high-friction conditions, with the toe of the swing foot contacting the ground and subsequently falling forward. These results imply that there is an optimal coefficient of friction for the ground to prevent slip- and trip-induced falls by people with less stable gaits, which may provide new insights into the design of shoes and floor surfaces for the elderly.

Lightweight materials with better resistance to sliding wear are prominent candidates for automobile brake drums, clutch pads and cylinder block applications to facilitate fuel economy. This attempt is reserved to cater to materials with higher tribological quality needs. Less dense foamy pumice stone particles were involved in three different percentages (5, 10, and 15 wt%) to reinforce lightweight AZ31 Mg alloy. A stir-assisted squeeze casting technique was pursued to process the composite and refine the grain structure. A phase detection, elemental mapping and microstructure study were done through X-ray diffraction (XRD), energy dispersive spectroscopy (EDS), and scanning electron microscopy (SEM), respectively. An experimental dry sliding wear scrutiny was administered using a pin-on-disc apparatus by considering: (i) ambient and elevated temperature environments and (ii) three different levels of loads. The results reveal a significant drop in wear loss and a frictional coefficient for 15% pumice-loaded composite than the base alloy. Post-wear examination acknowledges the fact that the ambient temperature wear is governed by adhesive-abrasive wear and high temperature is by abrasive wear mechanisms. Worn-out scrutiny authenticates the presence of oxide layers and their role in lubrication. A comparative study with previous works upholds the novel magnesium composite is the right candidate for the mentioned automobile applications.

This work studied spark plasma sintered Ti48Al48Cr2Nb2 alloy for their nanoindentation and wear properties. Results showed an improvement in nanoindentation properties of the compacts with an increase in holding time from 5min to 7.5min for the heating rate of 50°C/min and 100°C/min. X-ray diffraction (XRD) analysis showed the intensity of diffraction peaks of two major crystalline phases of Ti3Al2.25Nb0.75 and γ-TiAl. Scanning electron microscopy (SEM) images of sintered compacts possessed varied microstructures due to different sintering parameters. The nearly lamellar structure showed a good balance of yield stress and fracture toughness. Wear tracks SEM analysis revealed the worn surface morphologies and the sample sintered for 7.5 min at the eating rate of 50°C/min sustained the least damage evident by the shallow grooves and narrow wear track. Profilometer measurements revealed the wear track depth and width, confirming the degree of wear for the samples sintered at varied conditions.

With burgeoning considerations over energy issues and carbon emissions, energy harvesting devices such as triboelectric nanogenerators (TENGs) are developed to provide renewable and sustainable power. Enhancing electric output and other properties of TENGs during operation is the focus of research. Herein, two species (Nb2S2C and Ta2S2C) of a new family of 2D materials, Transition Metal Carbo‐Chalcogenides (TMCCs), are first employed to develop TENGs with doping into Polydimethylsiloxane (PDMS). Compared with control samples, these two TMCC‐based TENGs exhibit higher electric properties owing to the enhanced permittivity of PDMS composite, and the best performance is achieved at a concentration of 3 wt. ‰ with open circuit voltage (Voc) of 112 V, short circuit current (Isc) of 8.6 µA and charge transfer (Qsc) of 175 nC for Nb2S2C based TENG, and Voc of 127 V, Isc of 9.6 µA, and Qsc of 230 nC for Ta2S2C based TENGs. These two TENGs show a maximum power density of 1360 and 911 mW m−2 respectively. Moreover, the tribology performance is also evaluated with the same materials, revealing that the Ta2S2C/PDMS composite as the electronegative material presented a lower coefficient of friction (COF) than the Nb2S2C/PDMS composite. Their applications for energy harvesting and self‐powered sensing are also demonstrated. [ABSTRACT FROM AUTHOR]

The working conditions of tools during plastic working operations are determined by, among other things, temperature, loads, loading method, and processing speed. In sheet metal forming processes, additionally, lubricant and tool surface roughness play a key role in changing the surface topography of the drawpieces. This article presents the results of friction analysis on the edge of the punch in a deep drawing process using the bending under tension test. A DC04 steel sheet was used as the test material. The influence of various types of titanium nitride and titanium coatings applied on the surface of countersamples made of 145Cr6 cold-work tool steel was tested by means of high-intensity plasma pulses, magnetron sputtering, and electron pulse irradiation. The influence of the type of tool coating on the evolution of the coefficient of friction, the change in the sheet surface topography, and the temperature in the contact zone is presented in this paper. An increase in the coefficient of friction with sample elongation was observed. Countersamples modified with protective coatings provided a more stable coefficient value during the entire friction test compared to dry friction conditions. The electron pulse irradiated countersample provided the highest stability of the coefficient of friction in the entire range of sample elongation until fracture. The skewness Ssk of the sheet metal tested against the coated countersamples was characterized by negative value, which indicates a plateau-like shape of their surface. The highest temperature in the contact zone during friction with all types of countersamples was observed for the uncoated countersample. [ABSTRACT FROM AUTHOR]

ABSTRACT The study investigated the potential of waste plastic oil (PO) as an alternative to petroleum‐based lubricants, specifically mineral oil. The rheological properties, dispersion stability, friction, and wear performance of PO were examined and compared with mineral oil. Results showed that PO demonstrated similar lubrication performance to mineral oil. To enhance the lubrication performance of PO, the study incorporated various concentrations of nano CuO solid lubricant additives, resulting in the formation of CuO nano lubricants. These lubricants showed an improvement in friction and wear by 20% and 44% compared with PO. Furthermore, the CuO solid lubricant additives were functionalized and incorporated in the same concentrations into PO, resulting in the formation of functionalized nano lubricants, which further lowered the friction and wear by 28% and 91% compared with PO. The novelty of the paper is that a simple chemical functionalization process that not only helped in improving its dispersion stability of additives in the PO, but also enhanced the wear performance. The mechanisms behind the enhancement of friction and wear performance were discussed. Based on these findings, it can be concluded that incorporating functionalized nano additives in PO improve friction and wear performance in mechanical components, promoting wider utilisation of PO. [ABSTRACT FROM AUTHOR]

This study highlights the impact of low amounts of MoS2 quantities on composite performance by examining the effects of ultrasonication exfoliated MoS2 at different loadings (0.1–0.5 wt%) on the mechanical and tribological parameters of epoxy composites. Even at low concentrations, the ultrasonication and exfoliation procedures greatly improve the dispersion of MoS2 in the epoxy matrix, enabling its efficient incorporation into the tribofilm during sliding. Optimum mechanical properties were demonstrated by the MoS2/epoxy composite at 0.3 wt%, including a modulus of elasticity of 0.86 GPa, an ultimate tensile strength of 61.88 MPa, and a hardness of 88.0 Shore D, representing improvements of 61.5%, 35.45%, and 16.21%, respectively. Corresponding tribological tests revealed that high sliding velocity (10 N load, 0.2 m/s) resulted in a 44.07% reduction in the coefficient of friction and an 86.29% reduction in wear rate compared to neat epoxy. The enhanced tribological performance is attributed to the efficient removal and incorporation of MoS2 into the tribofilm, where it acts as a solid lubricant that significantly reduces friction and wear. Even though an ultra-low amount of filler concentration was added to the composite, a unique finding was the high MoS2 content in the tribofilm at higher sliding speeds, enhancing lubrication and wear protection. This study establishes that even ultralow MoS2 content, when uniformly dispersed, can profoundly improve the mechanical and tribological properties of epoxy composites, offering a novel approach to enhancing wear resistance. [ABSTRACT FROM AUTHOR]