Tribological Tests Research Articles

Enhancing Mechanical and Tribological Properties of Epoxy Composites with Ultrasonication Exfoliated MoS2: Impact of Low Filler Loading on Wear Performance and Tribofilm Formation.

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.

Synergistic Effect of Polyurethane on Pore-Sealing and Lubrication of Microarc Oxidation Coating.

Microarc oxidation (MAO) is a widely used surface treatment technology. However, its processing inevitably leads to the presence of micropores, microcracks, and other defects in the MAO coating. These defects lead to suboptimal tribological performance and diminished corrosion resistance of the MAO coating. Thus, this study proposed a new pore-sealing method with environmental protection and high efficiency. Polyurethane reactive (PUR) composite coating was prepared on the surface of MAO coating. The sealing effect of the PUR sample was analyzed using scanning electron microscopy (SEM). The molecular structure and elemental changes of the coating were analyzed using X-ray photoelectron spectroscopy (XPS). The tribological properties were analyzed using a tribological testing machine, and the corrosion resistance was tested using an electrochemical workstation. The test results show that the lubricity and corrosion resistance of PUR sample are improved significantly compared with MAO coating. When the mass fraction of PUR is 3 wt %, the PUR sample shows the best lubrication performance, and the coefficient of friction decreases by 70.8%. Compared with the traditional sealing technology, this experimental method is simple and low-cost and has a wide application prospect, which promotes the development of MAO technology.

Comparative analysis on high temperature tribological behaviour of additive manufactured and cast AlSi10Mg alloy

Abstract In recent years, additive manufacturing (AM) of AlSi10Mg, a material widely used in the aerospace and automotive sectors, has gained considerable interest for its ability to produce intricate shapes with improved mechanical properties. This proposed study aims to experimentally assess the high-temperature tribological performance of as-printed AlSi10Mg and compare it with traditionally cast AlSi10Mg to determine its suitability for high-temperature tribological applications. Samples of AlSi10Mg were manufactured via powder bed fusion, followed by tribological testing at elevated temperatures (30 °C, 100 °C, 200 °C, and 300 °C). The performance of both printed and cast AlSi10Mg pins was compared against an EN31 disc. The microstructure, worn surface, and wear debris of both printed and cast AlSi10Mg were examined using XRD and SEM with EDX analyses. As the load and temperature increase, both printed and cast AlSi10Mg materials demonstrate an increase in wear rate and friction coefficient. The wear rate of printed AlSi10Mg decreased by 60 % compared to cast AlSi10Mg at higher temperatures. There is a consistent trend in the coefficient of friction between printed and cast AlSi10Mg samples at low temperatures and loads. Abrasive wear predominantly occurs in both printed and cast AlSi10Mg samples at 30 °C within a load range of 10 to 20 N, while adhesive wear predominates in the same samples at temperatures ranging from 100°C to 300 °C with an applied load of 30 N. At low temperatures, smaller wear debris is observed, whereas at high temperatures and under a load of 30 N, larger wear debris is observed for both cast and printed AlSi10Mg samples.

Functional properties of expanded austenite generated on AISI 316L by plasma nitrocarburizing using different active screen materials

Abstract This study investigates the functional properties of the expanded austenite layers generated on AISI 316L austenitic stainless steel resulting from active screen plasma nitrocarburizing using different active screen materials, i.e. steel or solid carbon. Treatments were conducted at 460 °C for 5 hours in a nitrogen-hydrogen feed gas, whereas for the treatments using a steel active screen, methane was added as carbon precursor. Additionally, the bias plasma conditions applied at the samples were varied between 0 kW and 1.25 kW. Samples were characterized by complementary microstructural and compositional investigations, surface roughness and hardness measurements, pin-on-disk tribological tests as well as potentiodynamic polarization tests in H2SO4 and NaCl electrolytes. The functional properties of the case are discussed based on the contents of nitrogen and carbon in the expanded austenite and on their effective diffusion depths. The results show that the usage of a carbon screen generally produces surfaces with uniform layer thickness, high hardness, improved wear resistance and a delayed tendency to pitting corrosion independent of the bias condition applied to the samples. When applying both screen materials at non-biased condition, the general corrosion resistance is slightly reduced under the conditions used, however, the layers generated using the carbon screen have a wear rate that is 3 times lower. It can be concluded that the carbon screen represents a robust treatment variant for austenitic stainless steels to produce sufficiently thick and wear-resistant surface layers in a short treatment duration, which still have the potential to maintain the corrosion resistance in different environments.

Enhancement of mechanical and tribological properties in glass fiber-reinforced polymer composites with multi-walled carbon nanotubes and ANN-based COF prediction

ABSTRACT The study investigated the effects of incorporating multi-walled carbon nanotubes (MWCNTs) into glass fiber-reinforced polymer composites on their mechanical and tribological properties. Experimental results demonstrated significant enhancements across various parameters. Microhardness increased by 25.03%, attributed to improved interfacial bonding and load transfer facilitated by MWCNTs. Tensile strength and modulus improved by 10.58% and 28.2%, respectively, indicating reinforced load-bearing capacity. Flexural strength and modulus increased by 33.78% and 36.29%, respectively, due to enhanced interfacial bonding. Inter-laminar shear strength (ILSS) exhibited a notable increase of 20.79% with MWCNT incorporation. Ity mpact toughness improved by 19.41% in Izod and 32.32% in Charpy tests, attributed to MWCNTs’ energy-dissipating properties and enhanced interfacial bonding. Tribological tests showed decreased wear and friction coefficients, along with reduced debris formation and fiber breakage in SEM analysis, indicating improved bonding between the matrix and fibers. Furthermore, an artificial neural network (ANN) model accurately predicted the coefficient of friction, aligning well with experimental values, offering potential for predictive modeling in composite material analysis. Overall, the incorporation of MWCNTs significantly enhanced mechanical properties and wear resistance of the composite material.

Formation of coatings from accelerated ions of fluorinated fullerene C<sub>60</sub>(CF<sub>3</sub>)<sub>12</sub>

The first results of the deposition of coatings from accelerated ions of fluorinated fullerene C60(CF3)12 are presented. The coatings were formed at room temperature on Si substrates from a beam of singly charged C60(CF3)+12 ions with an energy of 5 keV, as well as from an ion beam, which also contained doubly charged C60(CF3)122+ ions and a certain amount of ionized fragments of molecules. The properties and structure of coatings obtained from accelerated ions of fluorinated fullerene are compared with the properties and structure of coatings obtained from accelerated C60 fullerene ions under the same conditions. According to X-ray photoelectron spectroscopy, fluorinated fullerene coatings contain about 4% fluorine. Investigations of the coatings structure and chemical bonds by X-ray photoelectron spectroscopy and Raman scattering showed that the presence of fluorine leads to decrease in the content of sp3 bonds and the formation of graphite-like sp2 structures. Coating hardness (H) and Young's modulus (E) compared to C60 ion coatings decrease from 36 to 18 GPa and from 245 to 133 GPa, respectively. The H/E ratio remained the same (~0.14). Tribological tests have shown for all coatings a friction coefficient close to 0.1. Also, all coatings are characterized by very low wear, less than 10–7 mm3/N∙m for coatings obtained from C60(CF3)12 ions, the contact angle is ~76°–78°. In the absence of fluorine, for the coating obtained from C60 ions, it is ~90°.

Investigation of Tribological Properties of Inconel 601 under Environmentally Friendly MQL and Nano-Fluid MQL with Pack Boronizing

Friction and high temperatures greatly affect the hardness and processing efficiency of superalloys. Therefore, it is important to provide a coating on their surfaces with a hard layer. In this study, pack boronizing was applied on Inconel 601 to improve its microstructure and tribological properties. In this regard, tribological tests were performed under MQL, nano-MQL1 (MQL + CuO), and nano-MQL2 (MQL + TiO2) environments. The research results showed that the lowest wear depth, friction force, coefficient of friction (CoF), and volume loss values were obtained in pack-boronized Inconel 601 in a nano-MQL2 environment. In the nano-MQL2 environment, the wear depth decreased by 17.81% (from 57.922 µm to 47.605 µm) with package-boronized Inconel 601 compared to as-received Inconel 601 at a 45 N load. Pack-boronized Inconel 601 experienced an average reduction of 30.23%, 41.60%, and 52.32% in friction force when switching from dry to MQL, nano-MQL1, and nano-MQL2 environments, respectively. It was also observed that the coefficient of friction (CoF) and volume loss values decreased with pack boronizing in an MQL/nano-MQL environment. In a nano-MQL2 environment at 15 N load, volume losses for as-received and boron-coated Inconel 601 were determined as 0.288 mm3 and 0.249 mm3, respectively (13.54% decrease). The findings of this study demonstrate that pack boronizing and MQL and nano-MQL techniques enhance the tribological characteristics of Inconel 601 alloys.

Novel insights into the synthesis and tribo-mechanical performance of high-entropy (Hf0.2Zr0.2Ti0.2W0.2Mo0.2)B2 ceramics

High-entropy (Hf0.2Zr0.2Ti0.2W0.2Mo0.2)B2 ceramics were synthesized using a two-step spark plasma sintering process, with densification at 1600 °C followed by sintering at 1850 °C. This method produced dense materials with excellent mechanical and tribological properties. Hardness values ranged from 18.85 GPa to 39.65 GPa, with a maximum Young’s modulus of 319 GPa. Micro-scratch tests showed high resistance to plastic deformation and minimal surface damage, highlighting durability under mechanical stress. Tribological tests at 15 N and 20 N loads demonstrated exceptional wear resistance, attributed to hard primary phases and lubricating soft secondary phases. These findings confirm the material’s robustness and show the effectiveness of the two-step synthesis in optimizing microstructure and enhancing properties, making it suitable for high-stress and wear-intensive applications.

Synergism of h-BN and La2O3 in improving the tribological performance of Al2O3 coatings

Wear is a significant cause of material loss, contributing to surface degradation of crucial components, notably within engineering sectors. This article is dedicated to enhancing tribological properties through the implementation of Al2O3-based ceramic coatings, specifically targeting situations where reciprocating sliding wear predominates. This study introduces lanthanum oxide (La2O3), a rare earth oxide, as a reinforcing material in Al2O3 coatings in varying weight percentages of 1.2%, 1.6%, and 1.8% respectively along with 3% hexagonal boron nitride (h-BN). The coatings were developed by the high-velocity oxy-fuel (HVOF) surface modification technique, with SS304 serving as the substrate. The porosity, hardness, and chemical composition of the developed coatings were examined. Additionally, reciprocating tribological testing of the coatings was conducted at two loads (5 N and 15 N) under dry sliding conditions. Results indicated that coating containing 95.4% Al2O3–3% h-BN–1.6% La2O3 reduced the porosity up to 50% and improved hardness by 46% compared to the 97% Al2O3–3% h-BN coating. The formation of the α-Al2O3 phase leads to an increase in coating hardness and a reduction in porosity. Notably, the coating comprising 97% Al2O3–3% h-BN exhibited the lowest coefficient of friction among all developed coatings under both loads. Furthermore, an increase in load led to a decrease in the coefficient of friction for all developed coatings. Furthermore, the addition of La2O3 (1.6 wt%) to the coating with 3 wt% h-BN exhibited the lowest wear at both loads. The findings also revealed increased wear at high loads for all developed coatings. SEM, EDS, and XRD analysis of the worn surfaces revealed the contribution of h-BN and La2O3 in enhancing friction behavior through the formation of oxides such as α-Al2O3, B2O3, Al8B2O15, and Al11La0.497O17, along with alterations in wear mechanism and the size of wear debris. The composite coatings developed in this study shall be helpful in advanced engineering applications.

Enhancing Lubrication Performance of Ga–In–Sn Liquid Metal via Electrochemical Boronising Treatment

ABSTRACTAs one of the liquid metals, Ga–In–Sn liquid metals can function as an advanced lubricant with high conductivity in a tribology system. It has already revealed advancements in several applications, such as coolants and electromechanical relays. However, Ga–In–Sn liquid metal shows poor lubrication performance on industrial metallic materials, which limits its application in engineering. In this study, the electrochemical boronising strategy was applied to improve the lubrication effect of Ga–In–Sn liquid metal on steel friction pairs. Electrochemical boronising treatment was performed to the base material AISI 52100, and a boronised layer with a thickness of around 64 μm was generated. Tribology tests were carried out on both boronised and original samples with the lubrication of Ga–In–Sn liquid metal (68.5 wt% Ga, 21.5 wt% In and 10 wt% Sn). Results show that the wear resistance of the tribo‐system reveals great improvement: The coefficient of friction decreases by 59% and the wear rate drops 85% compared to the steel/steel friction pair. EDS and XPS results show that a tribofilm consisted of Fe/Ga was in situ–generated on the wear scar of the boronised sample, which results in the synergy effect between the boronised layer and the Ga–In–Sn liquid metal. Therefore, we provided a robust strategy to enhance the lubrication performance of Ga–In–Sn liquid metal on a steel friction pair by using electrochemical boronising treatment, which could broaden the application field of Ga–In–Sn liquid metals.

The Influence of Temperature in the Wire Drawing Process on the Wear of Drawing Dies.

This paper presents a wear analysis of tungsten carbide drawing dies in the process of steel wire drawing. The finite element method (FEM) analysis showed a significant correlation between drawing die geometry, single reduction size and drawing speed on the rate of drawing die wear. It has been shown that in steel wire drawing at higher drawing speeds, intense heating of the drawing die occurs due to friction at the wire/drawing die interface, leading to premature wear. Tribological tests on the material for the drawing die cores (94%WC+6%Co) confirmed the gradual abrasion of the steel and carbide sample surfaces with the "products" of abrasion sticking to their surfaces. The increase in temperature increases the coefficient of friction, translating into accelerated wear of the drawing dies.

Technological solutions for applying special coatings to increase wear resistance of machine parts and components

Subject of research: technology for applying alloyed diamond-like coating (DLC), the influence of the atmosphere of the working area on the results of work. Purpose of research: search for the optimal alloyed diamond-like coating for loaded parts of a car transmission in order to ensure the required service life of the unit. Methods of research: all coatings, the research results of which are described in this article, were obtained by reactive magnetron sputtering. Main results of research: an analysis of the structural-phase state of a number of coatings is provided: containing chromium, titanium and silicon, obtained by magnetron sputtering in argon-acetylene-nitrogen atmospheres. Data are presented on the phase composition and size of coherent scattering regions, as well as the relationship between the structure and mechanical properties of the APP. A basic scheme for tribological testing of coatings has been determined, and the obtained nanocomposite structures of the APP are analyzed.

An injectable self-lubricating supramolecular polymer hydrogel loaded with platelet lysate to boost osteoarthritis treatment

Globally, osteoarthritis (OA) is the most prevalent joint disease and is characterized by infiltration of M1 macrophages in the synovium, anabolic–catabolic imbalance of the extracellular matrix (ECM), increased articular shear force and overproduction of reactive oxygen species (ROS). Disease-modifying OA drugs are not yet available, and treatments for OA focus solely on reducing pain and inflammation and have limited therapeutic effect. Herein, we developed an injectable self-lubricating poly(N-acryloyl alaninamide) (PNAAA) hydrogel loaded with platelet lysate (PL) (termed “PNAAA@PL”) for treating OA. Tribological and drug release tests revealed suitable lubrication properties and sustained release of bioactive factors in PNAAA@PL. In vitro experiments showed that PNAAA@PL alleviated interleukin-1β (IL-1β)-induced anabolic–catabolic imbalance of chondrocytes and repolarized pro-inflammatory M1 macrophages to the anti-inflammatory M2 phenotype via intracellular ROS scavenging. Additionally, the PNAAA@PL hydrogel enhanced the migratory capacity and chemotaxis ability of stem cells, which are essential for chondrogenesis. In vivo, the functionalized PNAAA@PL hydrogel acted like synovial fluid following intra-articular injection into a rat OA model with anterior cruciate ligament transection, ultimately attenuating cartilage degeneration and synovitis. According to molecular mechanism studies, PNAAA@PL repairs cartilage in the OA model by inhibiting the NF-ĸB pathway. Overall, this self-lubricating PNAAA@PL hydrogel offers a comprehensive strategy for preventing OA progression by engineering a biophysiochemical microenvironment to generate high-quality hyaline cartilage.

Optimization through combined compromise solution and weight determination through SHANNON-ENTROPY for multi criteria decision making in tribological testing of ultrahigh molecular weight polyethylene nano-composite in SBF environment and compression testing with it’s invitro analysis

Aluminium oxide and graphene reinforced with ultrahigh molecular weight polyethylene (UHMWPE) composites offer significant potential for prosthetic and implant applications due to their unique combination of properties. In this article, a series of aluminium oxide and graphene reinforced with ultrahigh molecular weight polyethylene (UHMWPE) composites were successfully fabricated through compression moulding. The average hardness of all the composites was observed to be higher than the UHMWPE (6.1 Hv). Composite U-15A-5 G was found to be the hardest with hardness of 10.5 Hv owing to strong bond between Al2O3 and UHMWPE. The compression strength of the U-15A-5 G material was about 81.936 MPa, which is 40.9% better than the pure UHMWPE. The compression modulus was about 330 MPa which is 22.2% higher than neat UHMWPE. Composite samples were tribo tested under simulated body fluid (SBF) lubricating environment. Using combined entropy-COCOSO method it was found that 50 mm/s speed, 200N load and 5% graphene are the optimum tribological parameters. with Cof of 0.04 and wear rate of 4.8745*10−4 mm3/Nm. Microstructure analysis indicated that long-range structured lamellar structures and microfibers were created between the crystals with the assistance of graphene layers. Apatite layer was also found on the sample. The apatite layer included phosphate and carbonate ions, which is good for in vitro bioactivity on polymeric films. This composite is a good candidate for prosthetics and implant components.

Structure-property relationship of pea protein microgels as fat analogues in Pickering oil-in-water emulsions: effect of salt addition.

The design of plant-based microgels provides a platform for food ingredients to enhance palatability and functionality. This work aimed to explore the modifying effect of salt addition (KCl) on the structure of pea protein microgel particles (PPI MPs), on the interfacial adsorption and characteristics of formed emulsions as fat analogues. Salt addition (0-200 mmol L-1) promoted a structural transformation from α-helix to β-sheet, increased the surface hydrophobicity (from 1160.8 to 2280.7), and increased the contact angle (from 56.73° to 96.47°) of PPI MPs. The electrostatic shielding effect led to the tighter packing of MPs with irregular structures and lowered the adsorption energy barrier. Notably, salt-treated PPI MPs could adjust their adsorption state at the interface. The discernible adsorption of PPI MPs with 200 mmol L-1 salt addition that possessed enhanced anti-deformation ability dominated the interfacial stabilization, whereas a relatively rougher stretched continuous interfacial film formed after spreading and deformation of 0 mmol L-1 MPs. A tribological test suggested that emulsion stabilized by MPs at 0 (0.0053) and 80 mmol L-1 (0.0068) had similar friction coefficients to commercial mayonnaise (0.0058), whereas a higher salt concentration (200 mmol L-1) lowered its oral sensation due to the adsorption layer and enhanced the resistance to droplet coalescence during oral processing. Salt could be a modifier to tune the structure of microgels, and further promote the formation and attributes of emulsions. This study would improve application attributes of PPI MPs in the design of realistic fat analogues. © 2024 Society of Chemical Industry.

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.

Methods of active friction control in the presence of lubricant compositions with mesogenic additives

Purpose of research. The aim of the study is to systematize the latest literature data related to the modulation of the friction coefficient by external fields when using lubricant compositions with liquid crystal mesogens and polymer composites.Methods. The article considers the methods of tribological tests using various schemes of friction pairs (cylinder-disk, pin-on-disk). Some commonly used methods of applying coatings to the elements of friction pairs are considered: ion beam-assisted deposition, chemical and physical thermal spraying, molecular layer deposition, photopolymerization, etc. Of the discussed methods of characterizing tribosystems, the following are indicated: dielectric spectroscopy, Raman scattering, polarization optical microscopy, nuclear-physical methods (positron annihilation spectroscopy and Xray diffraction).Results. The article systematizes modern trends in the development of modulated modes of operation of tribological circuits with lubricant compositions containing liquid crystals and polymer composites. The following approaches are used to implement active control of the friction coefficient: 1) modulation of friction by an electric field, 2) modulation of friction by a temperature field, and 3) modulation of friction on optical gratings under light irradiation. These approaches take into account the changed characteristics of the lubricant associated with the use of mesogenic additives, modes of exposure to electromagnetic and thermal fields, electrical characteristics, geometry of the surface of friction pairs, and provide the values of tribological characteristics (friction coefficient and wear) that are achieved as a result of friction modulation.Conclusion. A positive effect of mesogenic additives of liquid crystals and polymers on tribological characteristics with active control of the friction coefficient has been established: a decrease in the friction coefficient is observed, which helps to reduce material wear.

Microstructural evolution and tribological behavior of HVAF sprayed FeCoNiCrMox (x=0, 0.2, 0.5, 1) coatings

High entropy alloy coatings with a unique microstructure and excellent mechanical properties show significant potential for development in friction-related applications. In this study, the microstructure, phases, hardness and tribological behavior of FeCoNiCrMox (x = 0, 0.2, 0.5, 1.0) coatings fabricated by HVAF spraying were investigated. The coating changes from a single FCC structure (x=0, 0.2) to a dual phase structure of FCC and σ (x=0.5, 1), accompanied by an expansion in the segregation regions of Cr and Mo elements. The hardness of coatings increased with higher Mo content. Tribology tests were carried out at room temperature using Si3N4 ceramic and GCr15 steel as counterfaces. The results demonstrate that, when paired with GCr15, the wear resistance of the coatings scale proportional with hardness. However, when paired with Si3N4, the coating wear rate exhibits an initial increase followed by a decrease. Notably, the FeCoNiCr and FeCoNiCrMo0.2 coatings exhibited milder friction and wear behavior when in contact with Si3N4 compared to GCr15 steel, attributed to the dominant oxidative wear. This study provides new insights and directions for the design of customized high-entropy alloy coatings based on specific friction conditions.

Investigating the Influence of Protic Ionic Liquid on the Triboelectrical Properties of Trimethylolpropane Trioleate (TMPO)

Under triboelectric conditions, where tribocharging accelerates lubrication failure, lubricants with enhanced electrical properties are essential. Trimethylolpropane Trioleate (TMPO) oil, derived from esters that possess good lubricating properties and wear performance but is lacking in terms of electrical properties which can be further improved when blended with Ionic Liquid. This study blends 1 – 5 wt% of Protic Ionic Liquid (PIL) into TMPO and evaluate the frictional and wear performances of the blends under 1 – 2 A current conditions to understand the behaviour towards the tribological properties of different blends of material. Electric currents ranging around 1 – 2 A are implemented to the custom-designed ball-on-disc tribometer, with a constant 4.5 V voltage supply and the static resistance are measured. Mechanical wear properties are observed after the tribological test with different samples. The frictional properties of all concentrations of PIL in TMPO showed significant frictional improvements with 1%wt PIL showed 53% better results indicating improvements in frictional properties and wear performance under 2A current conditions, owing to its lowest film resistivity of 0.14 mΩ.

Modeling wear of different surface layers of agricultural tools in soil abrasive mass

Uniform quantitative measures have not been developed to identify the areas with the greatest intensification of tool wear. Therefore, this paper developed original approach to assess the wear of cutting elements by identifying the intensity of local volumetric wear. A tribological test was conducted under natural operating conditions in two soil types: sandy loam and loam. The specimens were mounted on a 9-tined cultivator with spring tines aggregated with an agricultural tractor. A method was developed to discretise the local volume changes of a component using surface scanning models developed from 3D scanning. The notion of the rake angle has been defined, allowing the assessment of changes in the shape of the element during wear. The practical usefulness of the developed method was verified on three types of surface layers, i.e. 38GSA steel, ELHARD70 deposited on it, and a G10 layer of carbide. For each of the tested variants, local volumetric consumption was defined based on the identification of the wear grid. These should be the basis for developing the technology of surface strengthening of elements. The work confirmed the complexity of the process of wear of working elements in natural soil conditions, presented in many research works. A different course of wear of the 38GSA steel and the Elhard 70 weld layer was shown, depending on the type of treated soil. In the case of samples made of G10 cemented carbide, the largest volumetric wear for heavy soil occurred outside the place of reinforcement application. The highest volumetric wear in the front zone was recorded for 38GSA steel in heavy soil. Wear results from the modelling are similar to those obtained from the experiment under natural conditions in light soil using the nominal model (CAD) and the actual friction surface.