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Highlights Determining the appropriate formulation in designing and developing brake friction materials is one of the most complex tasks. This study investigates the synergistic effect and optimization of twaron fiber on the fade and recovery performance of brake friction composites. For this purpose, a series of friction materials containing varying amounts of twaron between 1 and 9 wt% were developed, and their characterization and tribo evaluation were carried out. The tribo performance of the composites was evaluated in a Krauss‐type friction test machine in line with the ECE R90 procedure in terms of their fade and recovery behaviors. It was noted that the fade‐recovery friction response of composites was affected when fiber is added; that is, an increase in fiber content improved the fade performance, friction fluctuations decreased, and a higher recovery response was observed. The fade and average coefficient of friction were found to be the main determinants, while recovery was found to be the stabilizer. Analytical hierarchy process (AHP) was used to determine the priority of importance of criteria in the performance evaluation, and VIKOR (multi‐criteria optimization compromise solution) was used for ranking evaluation. The formulation with a concentration of twaron 7 wt% was found to have exhibited an optimal braking performance. The worn surfaces scanning electron microscope (SEM) study confirms the general friction and wear mechanisms of friction layers with fiber content. Development of twaron pulp‐reinforced eco‐friendly brake friction composites. Use of MCDM approach in the development of BFCs for braking applications. VIKOR optimization positioned 7 wt% twaron‐addition BFC as the optimal choice. It was observed that fiber amount is effective on the behaviors of composites. [ABSTRACT FROM AUTHOR]

ABSTRACT Objective Materials and Methods Results Conclusion Clinical Significance To evaluate the effect of staining, glazing, and polishing of stabilized zirconia with 5 mol% of yttrium oxide (5Y‐TZP) on the wear behavior of opposing tooth enamel.The plane specimens of 5Y‐TZP were divided into 6 groups (n = 10), according to surface treatment: as sintered, staining, glazing, polishing, staining followed by glazing, and staining followed by polishing, and positioned against tooth enamel during the two‐body wear test (20 N, 2 Hz, until completing 300,000 cycles). The wear rates of tooth enamel were evaluated using a profile projector and a digital pachymeter as a measure of vertical height loss. The data were analyzed by one‐way ANOVA and a Tukey post hoc test (α = 0.05).Polishing reduced the vertical height loss (p < 0.001) while there was no difference among other groups.Polishing is recommended as a finishing procedure to reduce the wear rates of tooth enamel, and finishing procedures (glazing or polishing) performed after staining did not affect the vertical height loss of tooth enamel.Polishing is the recommended finishing procedure for preshaded 5Y‐TZP to reduce the wear rates of opposing tooth enamel. Staining is applied to the occlusal surface to reproduce the pigmented groove appearance, and glazing or polishing performed after staining did not affect the wear rates of opposing tooth enamel. [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]

Acetabular cup liners made of ultra‐high molecular weight polyethylene (UHMWPE), in hip implants fail mostly due to wear debris generation and poor wear resistance. Consequently, strengthening UHMWPE becomes essential. The current work exhibits how the addition of 5 vol% carbon nanotubes (CNT) and functionalized carbon nanotubes (fCNT) in UHMWPE (denoted as U) affects the mechanical properties (hardness, elastic modulus) and tribological properties (wear resistance) of biocomposites. To form a composite, powders were mixed using a planetary centrifugal mixer followed by freeze‐drying to disperse‐CNTs, followed by its compression molding at 220°C for 1 h at 10 MPa. With the addition of CNT and fCNT, ≥95% densification was obtained for all samples resulting an increase in hardness and elastic modulus from 74.96 MPa to 168.11 MPa (124%) and 1.65 GPa to 2.96 GPa (79%), respectively, which led to the reduction in wear rate from 12.5 × 10−5 mm3/Nm (U) to 2.5 × 10−5 mm3/Nm (UfCNT). The amount of apatite formation enhanced from U (58.2%) to UfCNT (65.1%) is confirmed via X‐ray diffraction and X‐ray photoelectron spectroscopy. Cell proliferation studies have validated the cytocompatible efficacy of U‐CNT composites with osteoblast‐like MG‐63 cells, making UfCNT as potential material for acetabular cup liners. [ABSTRACT FROM AUTHOR]

Large gas engines are typically applied to compensate for peak loads and grid instabilities in the electric power supply. A key component of these engines is the spark plug. Because of the harsh conditions encountered in their use, the spark plug electrodes are subject to significant wear. Conventional electrodes are expensive due to the precious metal alloys they contain. As an alternative, ceramic materials from the groups of silicide, carbides, and nitrides were selected for preliminary experiments that investigate functional as well as mechanical properties and wear behavior. Because of the harsh conditions during operation, the new materials must have a high melting temperature, good thermal shock resistance, high thermal conductivity, and high corrosion/oxidation resistance as well as high density. It was found that the mechanical and thermomechanical properties of certain ceramic candidates are sufficient for application as spark plug electrodes. Furthermore, the chosen ceramic materials achieve an adequate performance in terms of secondary voltage trace and ignition behavior. However, wear resistance may not be sufficient for service times longer than the service time of existing spark plugs and further research is still necessary before ceramic electrodes may be established as a commercial alternative to existing electrodes. [ABSTRACT FROM AUTHOR]

Solid lubricants are added to polymers to upgrade their tribological properties, especially in cases where adhesive and abrasive friction are valid. However, there are not enough studies on the effects of solid lubricants on particle erosion. This study investigated the effects on solid particle erosion behavior of three different well known solid lubricants (molybdenum disulfide, polytetrafluoroethylene, and graphite). These solid lubricants were added at three different ratios (5, 10, and 15 wt.%) to the two different type (rigid and toughened) epoxy resins. Garnet abrasive particles (180–400 μm) were blasted to the sample surface under 1.5 bar for 15 s to conduct solid particle erosion tests. The erosive wear mechanisms of neat and solid lubricant‐reinforced epoxy resins were investigated in relation to the epoxy type, solid lubricant type, and solid lubricant reinforcement ratio. Statistical analysis was performed according to response surface methodology to support the experimental results, and ANOVA tables were obtained. The wear and deformations that occurred on the surface after solid particle erosion were examined using a noncontact optical profilometer system and scanning electron microscopy, and a significant relationship was detected between the deformation on the surface and particle erosion. Analysis results showed that the factor causing the greatest erosion rate change was the epoxy resin type. Finally, it has been observed that all solid lubricants reduce the erosive wear resistance, and this resistance decreases as the weight ratio increases. Highlights: Investigations were conducted into the erosion behavior of two types of epoxy resins: rigid and toughened. The toughened epoxy resin exhibited greater resistance to erosion. Although it has the same type of content, on average, rigid epoxy worn 2–4 times more than toughened epoxy.The effect of adding polytetrafluoroethylene tended to increase the erosion rate of both rigid and toughened epoxy resin less than that of other solid lubricants.Graphite particles increased the erosion rate of toughened epoxy by 1.5–3 times and that of rigid epoxy by 2–3 times, depending on the value of the reinforcement ratio.MoS2 increased the erosion rate of toughened epoxy by 1.5–3 times and that of rigid epoxy by 2–3 times.Using a noncontact optical profilometer (for investigating surface topography), it was proven that there is a significant relationship between the erosion rate and roughness characteristics. Wear mechanisms were identified by SEM analysis. [ABSTRACT FROM AUTHOR]

Highlights The characterization of S. persica (Salvadora persica) extract, which involved evaluating its antibacterial activity, demonstrated the extract's strong efficacy. Additionally, incorporating it into PMMA/HA showcased the composite's good antibacterial activity. The objective of this work is to evaluate how the incorporation of S. persica extract affects the wear resistance of the dental composite PMMA/HA, considering the critical importance of wear resistance in dental applications. The wear response of this biocomposite was tested against an Alumina ball using a pin‐on‐disc tribometer. Initially, the hydroxyapatite (HA) micro particles demonstrate a remarkable influence on wear behavior when incorporated at an optimal percentage (10%wt). This optimal inclusion rate not only significantly increases the wear rate but also instigates a shift in the wear mechanism, favoring abrasive wear while minimizing adhesive wear comparing to PMMA. The addition of the extract nanoparticles to the composite PMMA/HA decreases the wear rate except the composite containing 10 wt% of each filler. Additionally, it introduces adhesive wear, in addition to the existing fatigue and abrasion wear. Thus, the composite PMMA/HA could accommodate up to 10 wt% of the S. persica extract as the optimal percentage that provides antibacterial activity to this biocomposite without exhibiting a deterioration in wear performance. The evaluation of the effect of incorporating S. persica extract, which provides antibacterial activity, on the wear resistance of the PMMA/HA dental composite generally demonstrates a reduction in this property. The addition of S. persica extract introduces adhesive wear in addition to the fatigue and abrasion wear already present in the PMMA/HA composite. The composite PMMA/HA can accommodate up to 10 wt% of S. persica extract without compromising its wear performance. [ABSTRACT FROM AUTHOR]

As it is known, Polytetrafluoroethylene (PTFE) is one of the most preferred polymeric materials for tribological applications. This study investigates the performance of PTFE and its composites under different tribological conditions. The effects of short glass fiber (GF), carbon particle (CP) and bronze particle (BP) reinforcement agents and their hybrid filling with molybdenum disulfide (MoS2) on sliding, erosive and abrasive wear were examined. Sliding tests were carried out with a ball‐on‐disc test apparatus, erosive wear tests were carried out with solid particle erosion and abrasive wear tests were carried out with a scratch test. It has been found that reinforcement agents improve sliding and abrasive wear resistance but worsen the erosion resistance. The hardness and contact angle of the samples were associated with their wear performances. Topographic and morphological analyzes of worn surfaces were performed using optical profilometer and scanning electron microscopy (SEM), respectively, and wear mechanisms were discussed. Highlights: Filling materials (glass fiber, carbon particle and bronze particle) increase the adhesion and abrasion resistance of PTFE, while decreasing its erosion resistance.The effect of hybrid addition of MoS2 solid lubricant on wear performances depends on the type of filler.There is a correlation between surface properties (hardness and contact angle) and wear performances.Optical profilometer and scanning electron microscopy were used to examine wear mechanisms. [ABSTRACT FROM AUTHOR]

Highlights This study advances the creation of biocomposite materials and serves to reduce and utilize agricultural waste such as pineapple leaf fibers (PALF). In this study, PALF‐reinforced natural rubber (NR) composites with included multi‐walled carbon nanotubes (MWCNT) were analyzed and characterized at various fiber loadings. The PALF content was ranged from 0, 10, 20 to 30 parts per hundred rubber (phr) while the MWCNT content was maintained at 10 phr. A two‐roll mill mixing process followed by molding was employed to fabricate the NR composites. Based on the curing behavior, tribological properties, and morphological analysis, it was confirmed that the hybrid reinforcement of the MWCNT and PALF improved the curing behavior, wear resistance, and morphology of the composites. The wear and friction properties of the composites namely coefficient of friction (COF), frictional force and specific wear rate (SWR) are significantly influenced by the applied loads. The COF of NR/30PALF and NR/30PALF/MWCNT composites is reduced to 0.80 and 0.72 respectively under 15 N of load. Physical properties namely the cross‐link density and swelling behavior of the composites ranged from 3.70 × 10−4 to 5.71 × 10−4 mol/cm3 and 207.81 to 386.17%, respectively. According to the results obtained, the best cure and wear behavior followed by the morphological analysis are observed in NR/30PALF/MWCNT composite. Among the samples tested, NR/30PALF composite exhibited the best performance in both cross‐link density and swelling behavior. It is anticipated that the findings of this study are expected to provide theoretical data for the design and optimisation of high‐performance automotive and footwear applications. NR/30PALF/MWCNT hybrid composite exhibited the shortest tc90$$ {t}_{c90} $$ The addition of MWCNT improved the wear resistance of the composites The reinforcement of PALF at 30 phr possessed the lowest swelling ratio and the highest cross‐link density of the composites The addition of MWCNT decreased cross‐link density of the composites [ABSTRACT FROM AUTHOR]

3D printing has shown promise in the development of notable sensing and health detection devices. Nonetheless, challenges remain in the concurrent development of highly durable wearable sensors with low‐friction surfaces. This challenge serves as a limiting factor in the operational lifespans of these sensors. In this study, a magnetically assisted 3D printing technique is developed to fabricate composites reinforced with magnetic Fe3O4@SiO2 nanochains (NCs) with dimensions of 60.2 µm in length (L) and 0.2 µm in diameter (D), indicating an L:D ratio exceeding 300. By applying a vertical magnetic field and extrusion flow field to the sensor's surface layer, the NCs can be arranged differently (together with the printed textures), reducing the coefficient of friction by 27.7% and improving the wear resistance. This approach is inspired by nacre, known for its impressive durability and resilience. A motion monitoring sensor with an extended lifespan is successfully fabricated by using liquid metal ink integrated with an anti‐wear layer. These findings offer significant insights into the evolution of wearable sensors, demonstrating their adaptability to multi‐material printing and resulting in improved performance and service lives. [ABSTRACT FROM AUTHOR]

Laser cladding technology is an advanced surface modification technique that has gained significant attention in various fields due to its energy savings, efficiency, and environmental friendliness. This paper discusses the preparation of AlCoCrFeNi high‐entropy alloy (HEA) coatings on the surface of a 5083 aluminum alloy using laser cladding technology under the Ar gas conditions. An orthogonal test system was used to optimize the laser cladding process parameters. The microstructure, as well as the mechanical, frictional, and electrochemical properties of the HEA coatings, were comparatively analyzed under the two process conditions S4 and S10. The results indicate that, under S10, the HEA coatings exhibit optimal surface quality. The coatings contained a mixture of Face‐centered cubic (FCC) and Body‐centered cubic (BCC) phases. Microscopic examination revealed three distinct areas: dark, gray, and off‐white. The coatings can significantly improve the wear and corrosion resistance of the alloy substrate. For the best results, it is set the laser power to 200 W, the laser scanning distance to .05 mm, and the laser scanning rate to 1250 mm/s. This present study offers a novel technical foundation for the fabrication of HEA coatings. [ABSTRACT FROM AUTHOR]

Highlights In polymer‐based dental composites, wear is a three‐body wear system mainly abrasive, because of the food particles and wear products suspended in the oral cavity, which are transferred to the microcavities of the surface of the replacements. Due to this fact, the incorporation of nanodiamond as reinforcement in these polymer–matrix composites, which promotes the creation of a solid lubricant tribofilm surface could be advantageous. With the reinforcement of nanodiamonds, BisGMA/TEGDMA‐based composites increase their microhardness by 95%–420%. A maximum hardness exceeding 65 HV is achieved with a reinforcement of 3.2 wt%. The specific wear rate of neat BisGMA/TEGDMA is near 10−4 mm3/Nm and the Archard's coefficient is 2.6 × 105. The incorporation of a content of 1.6 wt% ND is enough to cause a diminution of ~78% in the friction coefficient and a reduction of the specific wear rate and Archard's coefficient of ~50%. Nevertheless, the addition of relatively high contents reduces the effectiveness of photoinitiation and photocuring, which is related to the scattering and absorption of light radiation by ND. This causes a significant decline in elastic properties starting at 50 μm from the surface. Photocuring polymer resin was successfully reinforced with nanodiamonds. Microhardness increases from 95% up to 420%, close to commercial composites. Friction coefficient and wear rate are reduced with 1.6 wt% nanodiamonds. High levels of reinforcement reduce the effectiveness of photocuring. [ABSTRACT FROM AUTHOR]

In this study, a small‐sized shredder machine equipped with spiral oriented double‐edged rotating and fixed blades was utilized to shred high‐density polyethylene (HDPE) waste. The performance of the shredder machine was determined based on the recycling and shredding efficiency, the percentage of retention, and the wear of its rotating and fixed blades. The wear of the blades was examined using an optical microscope, a scanning electron microscope, an energy dispersive x‐ray, and an x‐ray diffraction. High recycling (~95 %–98 %) and shredding (~66 %–70 %) efficiency, and low percentage of retention (~1.2 %–4.1 %) indicated a reliable performance of the shredder machine. The rotating blade exhibited higher wear at the back end, compared to the front end for the fixed blade. The wear of the blades was due to scratching and edge chipping. Formation of iron oxides during shredding did not cause significant changes in the hardness of the blades. Based on the evaluation, cost‐effective and time saving maintenance of the shredder blades could be achieved by gradual maintenance starting from the blade exhibited high wear. [ABSTRACT FROM AUTHOR]

As an essential mechanical component, a rolling bearing can exhibit multiple failure modes that may occur independently or in correlation with one another. A reliability analysis method that meticulously accounts for the interdependencies among various bearing failure modes is presented in this paper. The examination of wear and fatigue failure mechanisms in rolling bearings is carried out using the Physics of Failure (PoF) approach. By considering the influence of uncertain variables, the limit state functions for individual failure modes are formulated through the application of stress‐strength interference theory. In the context of wear failure, the limit state function is derived using working clearance as the characteristic quantity. On the other hand, the limit state function for fatigue failure is constructed with a focus on fatigue damage accumulation. The Copula function is used to characterize the relationship between wear failure and fatigue failure, and a reliability calculation model for rolling bearings is developed, considering the correlation between these failure modes. Ultimately, the proposed method is utilized to assess the reliability of bearings under two different sets of test conditions. The feasibility of this method is confirmed through test data, demonstrating its effectiveness in predicting bearing reliability. Through the application of this method, engineers can optimize bearing size parameters, select appropriate initial clearances, and enhance the reliability design of bearing. [ABSTRACT FROM AUTHOR]

In the present work, hybrid composites made of Al2214 alloy with B4C and graphite were produced by using a liquid metallurgical process. Al2214 alloy was utilized to create hybrid composites that had 1.5–6 wt% of B4C particles and a constant 3 wt% of graphite particles. Microstructural analysis using scanning electron microscope (SEM), energy dispersion spectroscopy (EDS), and X‐ray diffraction (XRD) was done on the produced composites. The density, hardness, ultimate, yield strength, and elongation as a percentage were carried out using ASTM E8 for tensile and E10 standard for hardness test. The wear behavior of Al2214‐B4C and graphite composites was examined as per ASTM G99 standard using a wear testing device under a variety of loads and rotation speeds. Graphite and boron carbide particles were equally dispersed throughout the Al2214 alloy, according to SEM photographs. Graphite and B4C particles were detected in the Al2214 alloy by EDS and XRD analyses. The density of Al alloy composites was decreased by adding dual particles to the matrix. The Al2214 alloy's hardness, ultimate strength, yield strength, and wear resistance were all enhanced by the inclusion of dual particles, which increased these properties by 15.4%, 40.4%, and 46.7%, respectively. The presence of hybrid particles in the Al2214 alloy was revealed by EDS and XRD patterns. The density of Al alloy composites was decreased by adding dual particles to the matrix. Tensile force micrographs provided further evidence of the unique fracture behaviors shown by the Al2214 alloy and its composites. In order to examine the wear mechanisms and different morphologies of worn surfaces, scanning electron micrographs were taken. [ABSTRACT FROM AUTHOR]

Highlights Graphite phase carbon nitride (g‐C3N4) has shown great promise as a functional filler in the field of friction. But at present, research in the field of friction mainly focuses on bulk g‐C3N4 or obtaining g‐C3N4 nano‐sheets through inefficient exfoliation strategies, which greatly limits its industrial applications. In the study, a simple and effective secondary calcination method has been developed to successfully fabricate ultrathin white g‐C3N4 nano‐sheets. The mass ratio of the same volume of bulk g‐C3N4 and white g‐C3N4 nano‐sheets was as high as 50:1. Subsequently, the tribological performance of epoxy (EP) composite coatings containing different contents of bulk g‐C3N4 and g‐C3N4 nano‐sheets were researched. The EP composite coatings containing 1 wt.% g‐C3N4 nano‐sheets possess the lowest wear rate and friction coefficient in all samples, which is attributed to the two‐dimensional planar structure and high specific surface area of g‐C3N4 nano‐sheets make it easier to transfer to the dual surface to form the excellent transfer film under the action of friction force, so that the friction mainly occurs between a dual surface and a transfer film, which effectively improves the tribological performance of the coatings. Ultrathin white g‐C3N4 nano‐sheets were prepared by secondary calcination. EP‐1 wt.% g‐C3N4 nanosheets show the best tribological properties. g‐C3N4 nanosheet is easy to transfer to dual surfaces to form transfer films. This work provides guidance for the application of nanofillers in tribology. [ABSTRACT FROM AUTHOR]

Highlights This study investigates the influence of hexagonal boron nitride (h‐BN) content on the mechanical and tribological properties of polytetrafluoroethylene (PTFE)/glass fibers/MoS2/h‐BN composite materials. Their tensile strength and hardness were measured to evaluate the improvement effect of h‐BN. The results indicate that h‐BN particles can enhance the tensile strength and surface hardness of the PTFE composites. Tribological properties were conducted under dry conditions using a ball‐on‐disk tribometer, and the worn surfaces were examined through scanning electron microscopy. The results reveal that the friction coefficient initially decreases and then increases with the increase of h‐BN content. The lowest friction coefficient (reduced from 0.118 to 0.088) and wear rate (reduced by 16.16% compared to the sample without h‐BN addition) is achieved with the addition of 0.05 wt% h‐BN. Additionally, Energy Dispersive Spectroscopy (EDS) analysis was conducted on the SiC balls to reveal the wear mechanism by analyzing the composition of the transfer film. Finally, molecular dynamics simulations revealed the movement and interactions of h‐BN and PTFE at different content. This study provides valuable guidance for the incorporation of h‐BN particles into PTFE composites. The addition of hexagonal boron nitride (h‐BN) enhanced the mechanical and tribological properties of polytetrafluoroethylene (PTFE) composites. The effect of h‐BN on the transfer film was quantitatively analyzed using scanning electron microscopy and EDS. Revealed the interaction mechanism between h‐BN particles and PTFE. [ABSTRACT FROM AUTHOR]

Highlights There has been growing interest in using sustainable and eco‐friendly products to produce engineering materials. For this purpose, composite material applications obtained from agricultural wastes are gaining popularity. This study examines the synergistic effect of rice husk and rice stalk wastes on the fade and recovery performance of brake friction composites. Brake friction materials were developed using rice husk and rice stalk separately and in two different weight percentages as a 5–10 ratio in the formulation. For comparison purposes, a reference brake pad using copper as a substitute and a commercially available brake pad were used. Various physical, mechanical and thermal properties were analyzed. The tribological behavior of friction composites was evaluated on the Krauss test device in line with the ECE R90 procedure. The worn surface properties were analyzed using scanning electron microscopy. Tribo test results of friction composites were taken as criteria for performance optimization. While the importance weight of the criteria was determined by AHP, the VIKOR method was used in the sorting of alternatives. The experimental results have revealed that rice husk‐added friction composites had a good coefficient of friction value with better fade and recovery performance compared to rice stalk‐added ones. Increasing the amount of rice husk and rice stalk in the formulation tended to decrease the fade performance; however, it has increased the wear rate and recovery properties. Optimization results have shown that the brake friction composite containing 5 wt % rice husk ranks first in meeting the desired tribological criteria. Cu‐free rice husk and rice stalk‐added friction composites were developed. Fibrous structure in the matrix developed the contact plateaus. Rice husk‐based tribo‐layer protected the composite from further wear damage. The addition of agro‐waste to friction composites exhibited good potential. [ABSTRACT FROM AUTHOR]

Highlights Glass fiber reinforced polymer (GFRP) composites can be subjected to different environmental conditions such as temperature, humidity, ultraviolet radiation, hydrothermal cycle, acidic and alkaline solution in environments where they operate. These environmental conditions cause different damage mechanisms in composites such as pore formation, micro‐cracks, delamination, fiber breakage, fiber/matrix interface separation, plasticization, swelling and surface color change. In this study, wear properties of hybrid glass fiber reinforced polymer composites exposed to various environmental conditions for constant load (60 N), speed (500 rpm) and 2 h were examined comprehensively, depending on material content and environmental conditions. In this experimental study, the service conditions in glass fiber reinforced composites were simulated using different artificial aging environments such as acidic environment, hydrothermal cycle and UV radiation. In addition to the material content, it appears that the environmental conditions to which composites are exposed has a significant effect on friction coefficient. Considering environmental conditions, it is seen that the acid environment and hydrothermal cycle have reduced wear resistance of GFRP composites, while UV radiation improved wear resistance of the composites. In C2 sample, the wear rates under different conditions are 1.87 × 10−14 m3/Nm in non‐treated sample, 6.05 × 10−14 m3/Nm in acid environment, 4.79 × 10−14 m3/Nm in hydrothermal cycle and 0.59 × 10−14 m3/Nm in UV radiation. Friction coefficient of glass fiber reinforced polyester (GFRP) is higher under aged condition compared to non‐treated. Glass fibers used in correct proportions can reduce friction coefficient in GFRP. GFRP exposed to environmental conditions has an important effect on wear. Acid environment and hydrothermal cycle has reduced wear resistance of GFRP. UV radiation improved wear resistance of GFRP composite. [ABSTRACT FROM AUTHOR]

The present paper describes the fabrication and wear behaviour of CaO and MgO added stabilized zirconia (ZrO2) ceramics produced by powder metallurgy method were examined and modelling with artificial neural networks was studied using the experimental data obtained. CaO/MgO added stabilized zirconia ceramics were fabricated by using a combined method of ball milling, cold pressing ‐ cold isostatic pressing and sintering. CaO and MgO in different amounts (0–8 %mole) were mixed with zirconia. These mixtures were prepared by mechanical alloying method. The green compacts were sintered at 1600 °C. The wear experimental results obtained were converted into data suitable for modelling with artificial neural networks. Wear Load, wear time, CaO and MgO data were used as artificial neural networks input variables. The amount of wear according to the pressing method was taken as the output variables of artificial neural networks. An artificial neural networks was established for the prediction of wear properties of zirconia pressed using the adaptive neuro fuzzy inference systems (ANFIS) learning technique. As a result, a high R2 value of 0.9187 for cold pressing samples and 0,9449 for cold isostatic pressing samples was achieved based on the approach of comparing the success of the model with the test data set and the result produced. [ABSTRACT FROM AUTHOR]

Ceramic composites are suitable materials to improve the surface characteristics of steel. Therefore, in this research, Ni–Cr oxide nanocomposite was coated on 304 stainless steel (SS304) by the electrophoretic approach. The effect of chemical composition and coating parameters (time and voltage) was investigated on morphology, corrosion, microhardness, and wear behavior. The nanocomposites were successfully synthesized in three different compositions (Ni–Cr oxides of 70–30, 60–40, and 50–50). The products were coated on the SS304 in 1, 2, and 3 min and 90, 110, and 130 V. Fourier‐transform infrared spectroscopy, X‐ray diffraction, transmission electron microscope, and field emission scanning electron microscopy analyses were employed to investigate the characteristics of the synthesized powder and resulting coatings. The hardness, wear properties, and corrosion resistance of the coating were studied by microhardness, ball‐on‐disk, electrochemical impedance spectroscopy, and polarization methods. The coatings deposited at 1 min and 110 V were sound and free of microcracks. The wear resistance increased by increasing Cr%, so the 50–50 coating showed the best wear resistance with a friction coefficient of.763 and wear mass of 1.6 mg. However, the coating 70–30 presented the highest microhardness of 180.28 Hv. The coating 60–40 had the best corrosion resistance with a corrosion current density of 5.92 µA/cm2. The corrosion resistance improved for thicker coatings. [ABSTRACT FROM AUTHOR]

Graphene nanoplatelet (GNP)–reinforced TiB2 + SiC composites were fabricated by reactive spark plasma sintering (SPS) from a TiC–B4C–SiC powder mixture with equal‐volume percentages, optimizing their SPS temperature and evaluating their unlubricated sliding wear against diamond. First, it is shown that during the heating ramp of the SPS cycle, TiC and B4C react according to the chemical reaction 2TiC + B4C → 2TiB2 + 3C, and that the thus‐formed C is graphenized as GNPs, leading to composites with microstructures consisting of a ceramic matrix of fine TiB2 and SiC grains with abundant randomly oriented GNPs at grain boundaries. It is also shown that this reactive SPS is optimal at 2000°C (under 75 MPa pressure and 5 min soaking), resulting in a very hard (∼28.5–29.9 GPa) and very tough (∼6.7(3) MPa m1/2) composite. And second, it is shown that these two properties and its proneness to develop an oxide tribolayer make this composite very resistant to unlubricated sliding wear against diamond (∼2.8(1)·108 (N m)/mm3), undergoing only very mild two‐body abrasion. Finally, opportunities for the fabrication of toughened and very hard ceramic composites for contact‐mechanical and tribological applications are discussed. [ABSTRACT FROM AUTHOR]

Functionally graded ceramic systems consisted of Al2O3/(Al2O3–ZrO2) and Al2O3/(Al2O3–Nd2Ti2O7) have been produced by gel casting. In Al2O3/ZrO2 systems, Al2O3 was gathered with three different Al2O3/ZrO2 mixtures with varying ZrO2 contents. For Al2O3/Nd2Ti2O7 system, Al2O3 layer was combined with 3 mol% Nd2Ti2O7‐doped Al2O3. All samples sintered at 1480 and 1540°C showed strong adhesion between layers without any crack formation. In the Al2O3/ZrO2 systems, both layers were intact; a distinct separation was observed, whereas a large reaction zone was observed for the Al2O3/Nd2Ti2O7 system as a consequence of reaction between both phases. The separation between layers for both systems was identified by SEM–EDX analyses. The hardness and wear tests of the samples showed that functional grading approach ensures combining various physical properties in a monolithic body. [ABSTRACT FROM AUTHOR]

The tribological performance of the tungsten carbide substrate (WC‐Co), improved by ceramic coatings, is still being reported in new studies that have been carried out to date. It has become a hot research topic that are widely applied in hard material research, especially in the tools manufacturing fields. This study was conducted to investigate the wear characteristics of a commercial cemented carbide tool (WC‐Co) coated with a physical vapor deposition chromium‐vanadium nitride film (CrVN), followed by a boriding process as a final thermochemical treatment. Tested in dry sliding contact against an alumina ball as a static partner, the tribological responses of the specimen were analyzed and compared with an uncoated specimen. Friction coefficients, calculated from volume loss, were around .58 for all specimens except the uncoated specimen at 10 N of applied load. Wear scar analyses revealed the occurrence of several wear mechanisms that is polishing, oxidation, wear debris formation, surface binder removal, grain fragmenting, and grain pull‐out. [ABSTRACT FROM AUTHOR]

In this work, boronitrogenated methyl epoxyoleate (BNMEO) was prepared by boronization and nitrogenation of methyl epoxyoleate (MEO). The tribological properties of BNMEO and MEO as bio‐based lubricating additives in a petroleum oil were determined on a four‐ball tribometer. The topographies, element compositions, and tribochemical species of the worn surfaces were analyzed by a scanning electron microscope, an energy dispersive X‐ray spectrometer, and an X‐ray photoelectron spectroscope, respectively. Results showed that both BNMEO and MEO, especially the former, were excellent in fortifying load‐carrying capacities and friction‐reducing and antiwear abilities of the oil under mild loads. However, their abilities in improving extreme pressure property of the oil under severe loads were very limited. The prominent ability of BNMEO in reducing friction and wear was characterized by well‐increased maximum nonseizure loads and decreased wear scar diameters and friction coefficients and was attributed to generation of a dense and robust boundary lubrication film which consisted of a matrix of BNMEO with inclusions of aminic compounds, boron oxide, iron oxide, and hydrocarbons, thanks to strong adsorptions and tribo‐oxidations of BNMEO on the metallic surfaces in the tribological processes. [ABSTRACT FROM AUTHOR]

Wear behavior of a fine‐grained dual‐phase high‐entropy carbide/boride ceramics was investigated using ball‐on‐flat dry sliding methods in air, applying rotational and linear reciprocation motion with SiC counterpart. The investigated system showed very high nanohardness of the carbide and boride grains with mean values of 37.4 ± 2.3 and 43.0 ± 2.9 GPa, respectively, with the microhardness of dual system HV1 29.4 ± 2.0 GPa. The stabilized friction coefficient values during the circular tests changing from.62 to.77. During the reciprocal test, the frictional coefficient values are very similar with an average value of.53. The specific wear rates during the circular motion were similar in the range from 4.65 × 10−7 to 1.68 × 10−7 mm3/N m. During the reciprocal test, the wear rates at 5 and 25 N were similar as in the case of circular motion, but at 50 N load, the wear rate increased significantly to the value of 9.11 × 10−6 mm3/N m. The dominant wear mechanisms in all cases were oxidation driven tribochemical reaction and tribolayer formation in boride grains and mechanical wear in carbide grains. During the linear reciprocation test, the loading mode created conditions resulted in relatively low coefficient of friction and very high specific wear rate. [ABSTRACT FROM AUTHOR]

To enhance the friction and wear performance of TC4 titanium alloy, micro‐arc oxidation(MAO) coating was fabricated on its surface, which was subsequently sealed with a modified graphene/epoxy resin coating to form a composite coating of micro‐arc oxidation ‐modified graphene/epoxy resin. The friction and wear performance of samples sealed by different methods are analyzed and characterized using a scanning electron microscope, an energy spectrometer, and friction and wear tester. The results indicate that the modified graphene/epoxy resin coating successfully combines with the micro‐arc oxidation coating and fills the pores, thereby enhancing the friction and wear performance of the composite coating. In tribological tests, compared with other samples, this composite coating has a lower friction coefficient and specific wear rate, showing excellent friction and wear performance, and its main wear mechanism is adhesive wear. Therefore, the fabrication of a micro‐arc oxidation ‐modified graphene/epoxy resin composite coating can improve the friction and wear performance of TC4 titanium alloy. [ABSTRACT FROM AUTHOR]

A hybrid of halloysite nanotubes decorated with titanium dioxide nanoparticles (HNTs@TiO2) was synthesized by the sol–gel method and then mixed with ultra‐high molecular polyethylene (UHMWPE) by melt compounding to enhance its wear resistance properties. The incorporation of HNTs@TiO2 increased the crystallinity as well as the hardness of UHMWPE nanocomposites, which benefited less prone to plastic deformation during the friction process. In addition, the UHMWPE/HNTs@TiO2 maintained a high ductility character with a slight decrease in tensile strength compared to pure UHMWPE. With the addition of 3 wt% HNTs@TiO2, the UHMWPE nanocomposite achieved a remarkably low friction coefficient of 0.073 and a reduced wear rate of 6.67 × 10−6 mm3/N·m. These values represented a 32.4% decrease in friction coefficient and a 43.9% decrease in wear rate compared to pure UHMWPE. The improvement in wear resistance was due to the dislodged TiO2 and HNTs had good synergistic rolling effects at the counterface. Furthermore, the wear scan morphology observation revealed that the transferred HNTs@TiO2‐based materials could help to improve the quality of the tribofilms, which alleviated the abrasive wear from the metallic counterpart. This work offers a feasible way to enhance the wear resistance of UHMWPE nanocomposite without sacrificing the high ductility for expanding its engineering applications. Highlights: TiO2‐decorated halloysite nanotubes were synthesized by the sol–gel method.The addition of HNTs@TiO2 maintained the high ductility character of UHMWPE.The UHMWPE composite with 3 wt% HNTs@TiO2 had the best wear resistance. [ABSTRACT FROM AUTHOR]

This study focused on the wear behavior of unidirectional, thick GF epoxy composites produced using the autoclave method. The thermal aging process was applied for 250 and 500 cycles to understand the wear behavior of the material as it ages over time. To evaluate the wear behavior of the samples, wear tests were carried out under three different loads (10, 20, and 30 N) and three different sliding distances (150, 300, and 450 m). Taguchi‐based regression analysis was used to analyze the experimental results. The results obtained were evaluated using ANOVA tables and main and contour graphs. When the test results are examined, it is surprisingly observed that the wear resistance of the composite material increases positively with the aging effect. With thermally aging while the coefficient of friction value of composite samples increases from approximately 0.12 to 0.3, the wear volume decreases from approximately 4 to 1.3 mm3. Taguchi based regression analysis showed that the relationship between wear and thermal cycle sliding distance and load can be established by reducing the number of experiments in wear studies. Highlights: Thermal aging effect on wear properties of thick GFRP was determined.Minimum wear volume and COF values were determined by applying ANOVA.It was determined that a load increment has the most impact on wear volume.Worn surface images supported the reduction in the wear rates of the thick GFRP.Empirical regression models developed for the mathematical prediction. [ABSTRACT FROM AUTHOR]

This study investigates the tribological and mechanical properties of poly‐ether‐ether‐ketone (PEEK) and polytetrafluoroethylene (PTFE) based composites with molybdenum di‐sulphide (MoS2) reinforcements. Polymeric composite materials have gained popularity in various tribology applications due to low weight, reduced wear and friction characteristics, and improved commercial aspects. MoS2 exhibits superior strengthening characteristics and improved tribological functionality depending on its concentration. Mechanical properties were assessed using micro‐scratch testing, whereas tribological characteristics were investigated using pin‐on‐disc arrangement in dry conditions. Counter face discs were made up of 316 L Steel with four different roughness characteristics obtained from common machining operations: polished, turned, milled, and grit‐blasted. Friction and wear results were analyzed under three loading conditions and four roughness characteristics. MoS2‐reinforced composites exhibited a scratch hardness that is roughly double that of PEEK and around ten times higher than that of PTFE. Simultaneously, adding 3 wt.% of MoS2 in PEEK and PTFE composite reduces both volumetric wear and friction significantly compared to other combinations of materials. This study can, therefore, be practically important to produce direction in order to make a composite such as PEEK‐PTFE‐MoS2 (1–3 wt%) to achieve tailored tribological performances based on system operational features such as load, speed, temperature, and roughness characteristics. Highlights: PEEK and PTFE based composites reinforced with molybdenum disulphide (MoS2).Pin‐on‐disc and scratch tests are considered for experimental analysis.3 wt.% of MoS2 base‐composite turned out to be the best performer.Investigation progresses with a variation of sliding speed and surface roughness. [ABSTRACT FROM AUTHOR]

Nowadays, researches on the use of alkali metal salts as friction‐reducing and anti‐wear oil additives are continuing. In this study, the tribological effects of heavy metal containing MoS2 and alkali metal salt CaF2 additives on pure engine oil (20W50) were investigated using block‐on‐ring tester configured as surface contact geometry. The tests were performed at various contact loads, revolutions, and additive ratios. The crystal structure of the additives and their effects on surface quality and surface roughness analysed by x‐ray crystallography, scanning electron microscope and profilometry. Moreover, Energy dispersive spectrometry was used for element detection on worn surfaces. Results indicated that additives of MoS2 and CaF2 can reduce the friction, increase the capacity of load‐carrying and the wear resistance of surfaces. The additives improved the operation of the base oil in boundary lubrication zone by increasing the tribofilm forming effect. It was observed that the CaF2 additive exhibited more stable friction behaviour, while the MoS2 additive has better protective effects against scratches on the block surface. [ABSTRACT FROM AUTHOR]

In the current experimental work, using secondary phase hard nano titanium carbide (TiC) particles as reinforcement, two different magnesium metal matrices i. e., AZ31B/TiC and AZ61 A/TiC composite materials were synthesized by friction stir processing. Using the traditional testing approach for the developed materials, the simultaneous gain in metallurgical, mechanical, electrical, and tribological characteristics compared to the base substrate was examined. The microstructure study results for AZ31B/TiC and AZ61 A/TiC composites showed a uniform distribution of reinforced particles as well as an evolution in grain size, from 82 μm to 4.2 μm and from 74 μm to 3.7 μm, respectively, which consequently contribute in a significant gain in the microhardness of both composites i. e., around 2.2 times and 2.67 times respectively, greater than the base metal. When compared to monolithic alloys, the synthesized AZ31B/TiC and AZ61 A/TiC composites showed improvements in the areas of tensile strength, compressive strength, and coefficient of friction up to 1.81 times, and 1.64 times, 1.74 times and 1.58 times, and 57.92 % and 58.47 %, respectively. Furthermore, these improvements in characteristics also increase the final strengthening of the nanocomposite and reduce electrical conductivity. [ABSTRACT FROM AUTHOR]

The coal indirect liquefied diesel soot (Coal‐to‐liquids diesel soot, CS) was collected by a self‐made soot trapper. CS was modified with cetyltrimethyl ammonium bromide (CTAB) and named as CS‐CTAB. The tribological properties of CS and CS‐CTAB in 10#white oil(10#WO) were tested on a WTM‐2E controlled atmosphere miniature friction and wear testing machine. The morphology, composition, and tribological mechanism of CS and modified CS‐CTAB were studied by using TEM, XPS, XRD, Raman, and other instruments. The results showed that CS modified by CTAB is wrapped and entangled in long chains. Their main structure components are all amorphous carbon with a small amount of graphite crystallites. The addition of CS‐CTAB (0.8 wt%) significantly reduces both AFC and wear rate, with reductions of 32.9% for AFC, and 65.6% for wear rate compared to no additive. The anti‐friction and anti‐wear effect of CS is greatly improved after being modified by CTAB. Mechanism analysis shows that CS as a lubricant additive, acts as a micro‐bearing in the friction process and falls off under the action of shear force to generate an independent graphite sheet, thus forming a graphite protective film on the surface of 304 stainless steel plate. However, CS has the defects of low graphitization degree, large particle size, and easy agglomeration. During friction, uneven adsorption of CS on the surface can worsen wear. However, CTAB modification can improve dispersion stability in 10#WO and effectively reduce wear on the friction surface. [ABSTRACT FROM AUTHOR]

Semi‐solid lubricant in the leg joints of insects is represented by tiny cylindrical fragments. The dynamics of lubricant behavior between contact surfaces at the joint scale are investigated using numerical simulation. Results of modeling show that lubricant fragments tend to stick together and form clots of varying shapes and sizes under the influence of shear motion. Formation of such clots, accompanied by constant loss and reproduction of the lubricant, allows maintaining of fluctuating clearance between contact surfaces and helps to reduce friction. Foreign contaminant particles penetrating an open insect joint are removed by the lubricant, to which they stick, reducing abrasive wear. [ABSTRACT FROM AUTHOR]

This study investigates the effects of filler content and type on the mechanical (tensile strength and impact resistance) and tribological properties of woven glass fiber‐reinforced composites (WGFC) produced using three different nanofillers (MgO, CuO, and Al2O3) at various loading levels (0.7, 1.4, and 2.8 wt%). Additionally, analyses of the artificial neural network algorithm were reported for the predictions of wear rate, mass loss, and coefficient of friction (COF) by given applied load, sliding distance, filler ratio, and filler type. The composites were fabricated using the hand lay‐up method. The filled composites were characterized using Fourier Transform Infrared (FTIR) spectroscopy, and the worn surfaces of the samples after the wear test were analyzed using Scanning Electron Microscopy (SEM). The wear resistance of the composite samples improved at 0.7 wt% CuO and 1.4 wt% MgO filler contents. At 200 m sliding distance and 1.4 wt% filler ratio, the highest wear ratio was determined as 55 mm3/m × 10−3 in the Al2O3‐filled composite, and the lowest was determined as 31 mm3/m × 10−3 in the MgO‐filled composite. At 1.4% filler ratio and 15 N load, the lowest friction coefficient was determined as 0.45 μ in MgO‐filled composite, and the highest was 0.56 μ in Al2O3‐filled composite. Al2O3 filler increased the mass loss and wear rate of the composite material. In Charpy impact tests, the maximum impact energy of 13.9 J/m2 was obtained with a 2.8 wt% Al2O3 filler content. Tensile tests showed an increase in tensile strength for all filler contents compared to unfilled composites. The highest tensile strength of 242.1 MPa was achieved with 0.7 wt% CuO reinforcement. Highlights: In all applied wear parameters and filler ratios, the Al2O3 filler adversely affected the wear resistance of the composite, while the MgO filler showed the best performance in terms of wear resistance.All types and ratios of fillers increased the tensile strength compared to the unfilled composite.Contrary to its negative effect on wear, the Al2O3‐filled composites exhibited the highest impact resistance.The prediction analysis of the tribological behavior of composite material using ANN reveals that the Levenberg–Marquardt algorithm fits very well. [ABSTRACT FROM AUTHOR]

The aim of the study was to evaluate the effects of erosion and abrasion on resin‐matrix ceramic CAD/CAM materials [CERASMART (GC); VITA ENAMIC (VITA Zahnfabrik); Lava Ultimate (3 M)] in comparison to feldspar ceramic (VITABLOCS Mark II, VITA Zahnfabrik) and resin composite materials (ceram.x universal, Dentsply Sirona). Daily brushing and acid exposure were simulated using a brushing apparatus and a solution of 0.5 vol% citric acid. Microhardness, surface roughness, and substance loss were measured at baseline and after simulation of 1 and 3 years of function. All materials showed a decrease in microhardness after 3 years and an increase in surface roughness (Ra) after 1 and 3 years. The Ra increase was statistically significantly lower for the resin‐matrix ceramics than for feldspar ceramic and similar to composite material. After 3 years, only feldspar ceramic showed no significant substance loss. In conclusion, resin‐matrix ceramics demonstrate reduced roughening compared to feldspar ceramics, potentially improving restoration longevity by preventing plaque buildup, but differences in abrasion resistance suggest the need for further material‐specific research. Future research should aim to replicate clinical conditions closely and to transition to in vivo trials. [ABSTRACT FROM AUTHOR]

Analysis of polyethylene (PE) wear in knee implants is crucial for understanding the factors leading to revision in total knee arthroplasty. Importantly, current experimental and computational methods for predicting insert wear can only be validated against true in vivo measurements from retrievals. This study quantitatively investigated in vivo PE wear rates in fixed‐bearing (FB) (n = 21) and rotating‐platform (n = 53) implant retrievals. 3D surface geometry of the retrievals was measured using a structured light scanner. Then, a reference surface that included the deformation, but not the wear that the retrievals had experienced in vivo, was constructed using a fully automatic surface reconstruction algorithm. Finally, wear volume was calculated from the deviation between the worn and reconstructed surfaces. The measurement and analysis techniques were validated and the algorithm was found to produce errors of only 0.2% relative to the component volumes. In addition to quantifying cohort‐level wear rates, the effect of mechanical axis limb alignment on mediolateral wear distribution was examined for a subset of the retrievals (n = 14 + 26). Our results show that FB implants produce significantly (p = 0.04) higher topside wear rates (24.6 ± 10.1 mm3/year) than rotating‐platform implants (15.3 ± 8.0 mm3/year). This effect was larger than that of limb alignment, which had a smaller and nonsignificant influence on overall wear rates (+4.5 ± 11.6 mm3/year, p = 0.43). However, increased varus alignment was associated significantly with greater medial compartment wear in both the FB and rotating‐platform designs (+1.7 ± 1.3%/° and +1.8 ± 1.6%/°). Our findings emphasize the importance of implant design and limb alignment on wear outcomes, providing reference data for improving implant performance and longevity. [ABSTRACT FROM AUTHOR]

Nanostructures as an inert additive to the lubricant act as a tiny friction reduction element by providing asperity filling, polishing, and film formation mechanism at the nanoscale dimension under the boundary layer regime. Here, we explore the synthesis and tribology application of iron‐carbon‐based nanoparticles encapsulated multiwall carbon nanotubes (Fe‐C‐CNTs). Three Fe‐C nanoparticles phase that is, Fe3C‐CNTs, Fe3C‐Fe‐CNTs, and Fe‐CNTs are synthesised. In particular, the emphasis here is on the effect of nanoparticle phase variation on the tribology property. The tribology property of the prepared nanomaterials is studied by dispersing it in commercially used Servo gearbox oil. The coefficient of friction and wear is found reduced in all dispersions compared to the base gearbox oil confirming the manifestation of nanoscale mechanisms at the tribo‐interface. It is revealed that the phase variation shows more impact on the alteration of friction coefficient compared to the dispersion concentration variation analysed using ANOVA two‐way technique. Further, the diameter and composition analysis of the wear scar is used to comprehend the underlying mechanism of the encapsulated particle phase variation. The findings suggest that the Fe‐CNTs dispersions are efficient in reducing friction to a larger extent but also promote the interface oxidation leading to enhanced wear and roughness whereas, Fe3C‐CNTs and Fe3C‐Fe‐CNTs are chemically stable providing smooth sliding and less wear. [ABSTRACT FROM AUTHOR]

The cross‐linked polytetrafluoroethylene (PTFE) and PTFE/carbon fiber (CF) composites were synthesized through electron beam irradiation in the molten state of PTFE at a controlled temperature of 340 ± 3°C under an inert gas atmosphere for this study. The wear resistance of raw (raw‐PTFE), irradiated modified PTFE (RM‐PTFE), and CF‐reinforced PTFE composites were evaluated using a friction and wear testing machine. The testing was conducted under varying ambient temperatures and dynamic loads. After irradiation, the samples were sectioned into specific sizes for subsequent testing purposes. Under the test conditions of 4.64 MPa positive pressure, 800 rpm speed, and a duration of 300 s at 20°C, the wear amount of PTFE after irradiation modification is significantly reduced from 1.4103 mm to only 0.0233 mm, representing a remarkable reduction by a factor of 60. Similarly, under the test conditions of 4.64 MPa positive pressure, 200 rpm speed, and a duration of 300 s at 20°C, the friction coefficient of PTFE after irradiation modification is substantially decreased from an initial value of 0.13 to just 0.03. The observed improvement can be attributed to the transformation of PTFE's crystalline form into spherulite, accompanied by a significant enhancement in the degree of cross‐linking within its molecular chain. The PTFE was supplemented with 10% CF prior to irradiation. Under the test conditions of a positive pressure of 4.64 MPa, rotation speed of 800 rpm, and a duration time of 300 s at 20°C, the wear amount of the composite material measured only 0.0007 mm, representing a reduction by a factor of 2000 compared to that observed for pure PTFE. This improvement can be attributed to the CF filler's high wear resistance properties and the composite's enhanced thermal conductivity. [ABSTRACT FROM AUTHOR]

In this article, the multifaceted challenges of abrasive wear are explored, delving into its impact on components across diverse industries such as automotive, aerospace, mining, manufacturing, and energy production. The introduction of hard eutectic niobium carbide (NbC) networks into a high C martensitic steel and its effect on abrasive wear properties specifically is investigated. Four ingots are casted with Nb contents of 0.01, 0.25, 0.5, and 1.0 wt% and a base compositions of Fe–1.0C–0.96Mn–0.22Si–0.26Cu–0.11Ni–0.50Cr–0.005V–0.012Nb to determine the influence of eutectic NbC on hardness and wear resistance. Microstructural evaluation performed using scanning electron microscopy, electron dispersive spectroscopy, and X‐ray diffraction reveals that the eutectic NbC networks are broken up and distributed in bands within the microstructure upon hot‐rolling. A general increase in material hardness and wear resistance with an increase in Nb content is observed as measured by dry sand/rubber wheel (DSRW) testing. Nb alloying leads to a 65% decrease in DSRW mass loss between the 0.01 and 1.0 wt% Nb alloys at an approximate rate of 6% per every 0.1 wt% Nb added. [ABSTRACT FROM AUTHOR]

The tribological performance of two polymeric friction modifiers, one based on an ester‐based compound and another based on an ethoxylated fatty ester and an organic friction modifier, oleamide, was studied at 50, 90 and 140°C using a Mini Traction Machine equipped with optical interferometry and electrical contact resistance. The ability to form surface film is found to vary among the friction modifiers and with temperature and rubbing duration. Despite a thinner film being formed, polymeric friction modifier (PFMs) exhibited lower friction and wear than oleamide at all the studied temperatures. Further, the PFMs reduced boundary friction more effectively at higher temperature. In accordance with lower boundary friction, a smoother surface topography characterized by low wear was exhibited by PFM lubricated surfaces at higher temperatures. Scanning electron microscopy‐energy dispersive x‐ray analysis and time‐of‐flight secondary ion mass spectrometry provided insights on the tribofilm formation. The improvement in the tribological performance of PFMs is attributed to temperature‐induced conformation transition of adsorbed polymer chains on the surface. The results are corroborated by data obtained from dynamic light scattering and gel permeation chromatography. [ABSTRACT FROM AUTHOR]

To study the influence of nickel addition on the microstructure, mechanical and lubricated wear properties of Zn‐40Al‐2Cu alloy, one ternary and five quaternary Zn‐40Al‐2Cu‐(0.5‐2.5)Ni alloys were made by permanent mold casting. The wear behavior of these alloys was studied using a block‐on‐cylinder type test machine, after examining their microstructural and mechanical features. The microstructure of Zn‐40Al‐2Cu alloy was comprised of aluminum‐rich α dendrites and a eutectoid α+η phase mixture. The addition of nickel caused the formation of intermetallic Al3Ni particles in the microstructure of this alloy. As the nickel content of alloys increased their hardness, friction coefficient, working temperature, and average surface roughness increased to certain extents but their strength, ductility, impact resistance, and wear volume decreased. However, the values of their wear volume and average surface roughness exhibited opposite changes with increasing nickel content. The worn surfaces of Zn‐40Al‐2Cu‐Ni alloys were observed to be characterized by smearing and scratching marks. Furthermore, the wear and mechanical properties of these alloys were correlated, and the results were discussed in terms of their microstructural features. Finally, it may be concluded that the nickel addition adversely affects the ductility of Zn‐40Al‐2Cu alloy but increases its wear resistance. [ABSTRACT FROM AUTHOR]

Objectives: To compare volumetric wear of lithium disilicate against different ceramic (3 mol% yttria‐stabilized (3Y) zirconia, 5 mol% yttria‐stabilized (5Y) zirconia, lithium disilicate, porcelain and enamel antagonists). Materials and Methods: Forty lithium disilicate (e.max CAD) specimens (n = 8/antagonist) were wet sanded to 1200grit SiC and mounted into a UAB wear device. Antagonist spheres (diameter = 4.75 mm) were made from polished 3Y zirconia, 5Y zirconia, lithium disilicate, porcelain and human enamel. A two‐body wear test was performed with 20 N load and 1.5 mm slide for 400,000 cycles at 1 Hz. 33% glycerin was used as a lubricant. Wear facets were measured with optical profilometry. Wear scar areas of antagonists were measured with digital microscopy. Scanning electron microscopy was performed on wear facets and scars. Vicker's microhardness was measured of all antagonist materials. All data were compared with 1‐way ANOVA and Tukey post‐hoc analysis. Results: Significant differences in lithium disilicate volumetric wear (mm3) occurred with various antagonist materials: 0.38 ± 0.01a (3Y zirconia), 0.33 ± 0.01b, (5Y zirconia), 0.16 ± 0.01c (lithium disilicate), 0.11 ± 0.03d, (enamel), and 0.07 ± 0.01e (porcelain). The lithium disilicate antagonist demonstrated a larger wear scar than other materials. Zirconia was the hardest material and enamel the least hard. Conclusions: Zirconia causes significant wear on lithium disilicate and lithium disilicate causes significant wear against itself. Clinical Significance: When selecting a material to oppose an existing lithium disilicate crown, a porcelain or lithium disilicate surface would cause significantly less wear to the existing crown. If an existing zirconia crown exists opposed to a prepared tooth, lithium disilicate may not be an ideal material selection to restore the tooth. [ABSTRACT FROM AUTHOR]

Carbon fiber–reinforced SiC ceramic matrix composites (C/C–SiC composites) with advantages of high wear resistance and corrosion resistance are of high application potential as ceramic bearings. In this study, the frictional and wear behaviors of C/C–SiC with different fiber orientations mating with Al2O3 and SiC balls, respectively, have been investigated. Results reveal that fiber orientation effectively affects the friction and wear properties of carbon–ceramic composites in paired friction experiments with ceramic balls. In comparison to C/C–SiC with unidirectional fiber orientation, C/C–SiC pads with randomly arranged fibers exhibited a more stable coefficient of friction and lower volume wear, presenting the best performance among the pads considered herein, which may have the potential to be applied to bearing materials. The factors affecting the formation of continuous tribo‐film, which influence the comprehensive performance, are researched. It is proposed that the amount of wear debris and the formation of SiC/SiC micro‐hard frictional pairs may inhibit or promote the formation of continuous friction film. The dominant wear mechanisms for friction pairs of C/C–SiC and ceramic are abrasive wear and oxidation wear. [ABSTRACT FROM AUTHOR]

The present paper reviewed the role of factors influencing the wear properties of iron alloy‐based coating material. In brief, these factors are categorized into four major types such as substrate properties, high‐velocity oxy‐fuel spraying parameters, heat treatment processes and wear testing parameters. Substrate properties include roughness, thermal resistance, and adhesive strength between substrate and coating materials. High velocity oxy fuel parameters include spray distance, oxygen flow rate, fuel flow rate, angle of spray, spray density, coating speed, thickness, number of coating layers etc. Erosion wear testing parameters include impact speed, impingement angle, erodent discharge, slurry concentration etc. Furthermore, erosion wear testing parameters are sub‐categorized into three types which are particulate‐based parameters such as size, shape and hardness of particle, impact‐based parameters such as angle of impact, impact velocity, and composition‐based parameters such as microstructure, physical and mechanical properties of materials. The annealing process speeds up the development of crystal phases. Therefore, to get the best coating materials, a detailed investigation and optimization of all the factors must be performed. [ABSTRACT FROM AUTHOR]

Titanium and its alloys are used to make dental implants because of its low density, high strength, and corrosion resistance. This paper describes the development of a potential biomaterial Ti‐10Nb by powder metallurgy utilizing four different compaction pressures and analyses its microstructural, physical, mechanical, electrochemical, biological, and tribological behavior under various situations. The alloys were fabricated using four different compaction pressures, that is, 600, 650, 700, and 750 MPa, and sintered in a vacuum atmosphere at 1000°C for 1.5 h. The density of the samples was measured using Archimedes principle. X‐ray diffraction and scanning electron microscopy equipped with energy dispersive spectroscopy were used to investigate the phase composition and microstructure, and a profilometer was used to examine the surface roughness of various samples. Vickers hardness tester was used to evaluate hardness, and a universal testing machine was used for compression testing. Corrosion and wear behavior were examined using a potentiostat and a Bio‐Tribometer, respectively. This Ti‐10Nb alloys consist of α + β phase, and have 16% highest porosity in sample compacted at 600 MPa. The samples compacted at 750 MPa achieved highest hardness, yield strength, compressive strength, and elastic modulus of 450 ± 29.72 HV, 718.22 ± 16.37 MPa, 1543.59 ± 24.37 MPa, and 41.27 ± 3.29 GPa, respectively. In addition, it also possesses highest corrosion and wear resistance with lowest icorr of 0.3954 ± 0.008 μA/cm2 and wear volume of (31.25 ± 0.206) × 10−3 mm3. These results indicate that the developed alloys have a variety of desirable properties, including high hardness, adequate compressive strength, good corrosion and wear resistance, apatite‐forming capability, and a low elastic modulus, which is advantageous for avoiding stress shielding. Therefore, it may be recommended to use it as a dental implant material. [ABSTRACT FROM AUTHOR]

Purpose: To measure the wear at the implant interface between the Grade 4 titanium (Ti) of the implant and frameworks fabricated using two additively manufactured alloys (Ti alloy and cobalt–chromium [Co–Cr]) pre‐ and post‐artificial aging. Material and methods: Three‐unit frameworks supported by two implants were additively manufactured (Atlantis; Dentsply Sirona) using Ti and Co–Cr dental alloys. Two implants (OsseoSpeed EV, Astra Tech; Dentsply Sirona) were torqued on each non‐engaging framework. The assembled implant–frameworks were secured into polyurethane foam blocks. Groups were created based on the material and surface assessed: framework (Ti‐framework and Co–Cr‐framework groups) and implant (Ti‐implant group). Two subgroups were created depending on the location: premolar (PM) and molar (M). Computed tomography images were obtained pre‐ (as manufactured) and post‐simulated mastication procedures. The pre‐ and post‐simulated mastication files of each specimen were aligned using the best‐fit algorithm using a metrology program. Wear was measured by calculating the volumetric discrepancies at the implant interface on 64 measurement points per area analyzed. Three‐way ANOVA and Tukey tests were used to analyze the data (α = 0.05). Results: The mean volumetric discrepancy values ranged from 0.8 to 3.1 µm among all the subgroups tested. The group (framework vs. implant) (p < 0.001) and tooth location (p < 0.001) were significant factors of the mean volumetric discrepancy values obtained. The framework group presented with significantly lower volumetric discrepancy mean values (1 µm) compared with the implant group (3 µm), whereas the premolar area obtained significantly lower mean volumetric discrepancy values (1.9 µm) compared with the molar location (2.3 µm). Conclusions: Volumetric discrepancies were found at the implant–framework interface tested between the pre‐ and post‐artificial aging measurements ranging from 1 to 3 µm after 1,200,000 cyclic loading that simulated approximately 12 months of function. [ABSTRACT FROM AUTHOR]

In this work, two zinc‐based metal–organic frameworks (Zn‐MOFs) with different morphologies were successfully produced by the surfactant‐mediated synthesis method. They were grown on the Polytetrafluoroethylene (PTFE)/polydopamine (PDA) to prepare PTFE/PDA/Zn‐MOFs fiber fabrics. Then the epoxy resin (EP) matrix was poured onto fabrics to prepare EP/PTFE/PDA/Zn‐MOF. PTFE was modified by introducing a PDA adhesion layer, which can provide absorption sites for Zn‐MOFs growth and improve the bonding strength with EP. The microscopic morphologies and structures of the PTFE and modified PTFE were studied. Compared with pure EP, the friction coefficient and specific wear rate of the EP/PTFE/PDA/ZnMOF2 composite were reduced by 67% and 91%, and the EP/PTFE/PDA/ZnMOF1 composite were reduced by 55% and 88%, respectively, which were due to the loading of ZnMOF2 onto the PTFE surface, improving the interfacial bonding between the PTFE and EP matrix and can prevent the PTFE fabric from coming out of the EP matrix. ZnMOF2 also presents its structural advantage: the unique thin layer structure plays a vital role in friction and wear reduction. [ABSTRACT FROM AUTHOR]

In the current study, the friction and wear properties of Furcraea foetida fiber‐reinforced epoxy composites were investigated. This study evaluated the effect of Furcraea foetida fiber content on the tribological behavior of composites. A water‐retting method was employed to extract the fibers, and resin transfer molding was used to fabricate the composites. The frictional force, coefficient of friction (COF), and wear rate were measured under dry test conditions and various applied loads (80, 100, 120, and 140 N). Microstructural analysis was conducted using scanning electron microscopy to investigate the surface morphology and wear mechanisms of the composites. The results revealed that the composite with 50 vol% of fibers exhibits the lowest frictional force and COF in both normal and parallel orientations with overall average COF of 0.43 in normal orientation and 0.42 in parallel orientation. Moreover, the composite with 60 vol% demonstrates the best wear resistance with an overall average specific wear rate of 2.1982 × 10−5mm3/Nm in normal orientation and 4.3478 × (10−5) mm3/Nm in parallel orientation. Overall, this study provides valuable insights into the tribological behavior of Furcraea foetida fiber‐reinforced epoxy composites and identifies the optimal volume fractions for improved friction and wear performance. Highlights: Higher vol% yields denser composites with minimized voids.Normal fiber orientation shows maximum SWR of 10.0614 × (10−5) mm3/Nm.Optimal frictional force and COF in 50 vol% composite.Enhanced wear resistance observed in 60 vol% composite.Higher vol% increases interfacial bonding and wear resistance in composites. [ABSTRACT FROM AUTHOR]

The primary focus of this paper is to review the latest developments in iron based amorphous/nanocrystalline high velocity oxy fuel coatings. The extensive development towards the enhancement in the mechanical properties such as micro‐hardness, compressive strength, adhesion strength etc. and comparative investigations are the key objectives set by the coating material scientist. The industrial application fields of iron alloy based coating are growing rapidly and owing to the rapid increase in industrial applications, there are many more advancements in the coating deposition techniques. In the present review, various factors influencing mechanical performance of high velocity oxy fuel coating material have been listed and ranked according to the level of influence. It can be concluded that the mechanical performance of coating materials is significantly influenced by coating parameters, including spray distance, oxygen fuel ratio, coating thickness, and number of layers. [ABSTRACT FROM AUTHOR]