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Polymer coatings have gained a lot of attention in the recent past because of their ability to be easily coated on complex shapes, their low cost, and their ability to reduce friction as compared to other materials. Polyether ether ketone (PEEK) is one such high-performance polymer that has gained significant attention in recent years due to its exceptional mechanical properties, chemical resistance, and thermal stability making it a prominent candidate for applications in industries. However, PEEK in its pristine form exhibits poor wear resistance with a moderate coefficient of friction (0.30–0.38). Many attempts have been made by several researchers to improve its wear resistance and lower the COF by developing composite coatings. Hence, in this review, we aim to summarize and present in detail the tribological evaluation of pristine PEEK and PEEK composite coatings by discussing the various methods adopted by the researchers to improve the properties of PEEK, the different types of reinforcements and various dispersion techniques used to develop PEEK composite coatings. By consolidating and analyzing the existing body of knowledge, we also aim to offer valuable insights into the development of more durable, high-performance PEEK nanocomposite coatings for a broad range of tribological applications. [ABSTRACT FROM AUTHOR]

This study examined the development of Fe2B (diiron boronize) coatings on the surface of 35NiCrMo4 steel through the thermochemical surface hardening process called boronizing. The morphology and thickness of the boronize coatings were assessed using Scanning Electron Microscopy (SEM) and optical microscopy (OM). A novel mathematical mass transfer model was developed to estimate the diffusion coefficients of boron in hard coating. The presence of uniformly distributed boronize coatings with a typical sawtooth pattern on the surface of the substrate was confirmed. The boronize coating's chemical composition and phase constituents were analyzed utilizing X-ray energy dispersive spectroscopy (EDS) and X-ray diffraction analysis (XRD). The study confirmed the presence of a single-phase boronize coating (Fe2B). Furthermore, microhardness tests indicated that the boronized specimen's surface demonstrated an average hardness of approximately 1953 HV. The wear study were conducted using the pin-on-disk method under dry debonding conditions at room temperature to estimate the coefficient of friction (COF) of the boronized (average ≈ 0.35) and untreated (0.725) specimens. The results revealed approximately 200% improvement in wear resistance due to the boronized coating. The empirical validation of the mathematical model was carried out for two additional boronizing conditions at 1223 K for 3 h and 1273 K for 1.5 h, resulting in an estimated percentage error of around 2.5% for both conditions. Additionally, an ANOVA analysis was performed, taking into account the temperature and time factors. The findings indicate that both factors exert a substantial influence on the dependent variable (u), with temperature (T) contributing 64.68%, time (t) contributing 27.37%, and the interaction of both factors (T × t) contributing 5.13%. [ABSTRACT FROM AUTHOR]

A problem has been noted regarding the admixture of fuel to a low viscosity lubricant in hybrid electric vehicles (HEVs). This is very detrimental to the wear and tear of engine operating components. In this study, the operating conditions of HEVs were analysed. Using X-ray fluorescence spectrometry (XRF), engine oils of two different viscosity classes were compared after the operating process and these data were compared with fresh reference samples. Attention was paid to the content of elements such as Ca, Zn, Mo, Sn, Cd, Fe Pb, Si, Cu, and Ni. The depletion of anti-wear additives, as well as the higher content of metallic wear products relative to the operated 5W30 (engine oil), contributed to the overall assessment of the lubricity of the 0W30 oil, as well as to the tribological results. Then, under laboratory conditions, oil samples contaminated with up to 1 to 8% fuel were subjected to rheological (mini AV-X viscometer) and tribological (four-ball tester) tests. The dependence of the local pressure at the metal-to-metal contact point in the kinematic node on viscosity showed the dissimilar nature of the used and fresh oil and the divergence of the domains for the two groups of samples. Increasing the fuel contamination of used oil above 4% drastically reduces the pressure responsible for maintaining the oil film. In order to improve lubricant performance during HEV operation in urban conditions, it was proposed to carry out extra-urban traffic driving in order to evaporate the fuel from the engine oil. A shorter oil change interval is also recommended. [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]

In this study, the tribological characteristics of TiN, AlTiN, and AlTiCrN coatings sliding against a SUS420J1 stainless steel pin were investigated in atmospheric and vacuum environments. The coatings were deposited on SUS440C substrates using the arc-physical vapor deposition technique. The friction and wear behavior of the coatings were evaluated based on the systematic analyses of the friction coefficient data as well as the physical and chemical state of the wear track. The results revealed that the friction coefficients of the SUS440C specimen and AlTiCrN coatings increased, whereas those of the TiN and AlTiN coatings decreased when the environment was changed from atmospheric to vacuum. It was confirmed that the formation of an oxide layer and adsorption of oxides on the surface were dominant factors that influenced the tribological behavior in the atmospheric environment. On the other hand, the compatibility, oxidation inhibition, and droplets of the surface mainly affected the frictional characteristics in the vacuum environment. The results of this work are expected to aid in the selection of proper coating materials for tribological systems operating in a vacuum. [ABSTRACT FROM AUTHOR]

Introduction: Friction drilling is an innovative method in hole-making for sheet metal applications, thin sheets of conventional structural alloy materials like copper, titanium, steel etc., even though there are other methods, such as thermal distortion for thewelding of nuts, riveting of nuts, and threading. For the last hundred years, researchers have focused on studying the development of this technique to maintain strength, hole roughness, hole geometry, hardness etc. It is interested in finding solutions for wear, tool life, and plastic deformation. Method: Friction drilling is also called a green hole-making process because this process uses the friction between the rotating tool and the workpiece. In this research, instead of regular HSS and Tungsten Carbide tools, the H13 tool steel is used, because the H13 steel tool has unique chemical compositions like chromium and molybdenum, which give high toughness, hot hardness, and wear resistance. Diamond-like-carbon (DLC) coating has been used in this research to enhance tool life and AZ31B magnesium alloy is used as the work material. Initially, in this research, the wear stability of the DLC-coated H13 tool was investigated, and later, the tool surface roughness and hole quality were verified. Results and Discussion: The material loss observed for the DLC-coated H13 steel tool in the pin-on-disk test was 0.05 g. This investigation used two different diameter tools, namely 3 and 7 mm. Research has concluded that the 7mmtool is better for friction drilling by seeing the roughness and hole quality. However, the conditions were that the spindle should rotate at 4,000 rpm and the feed rate of the tool to be at 200 mm/rev. [ABSTRACT FROM AUTHOR]

This study investigated changes in the crystal lattice, tribological properties and friction mechanism of AISI 316 steel irradiated with swift 160 MeV xenon ions. The irradiation process caused the increased roughness of the steel surface and the swelling of the material. The thickness of the irradiated layer increased by about 13 nm. Following irradiation with the fluences 2.5 × 1014 and 3.2 × 1014 (Xe24+/cm2), martensite formed in the surface layer. Fluctuating changes were also observed with respect to the coefficient of friction and the degree of wear of the AISI 316 steel samples. Irradiation also increased the microhardness of the steel. [ABSTRACT FROM AUTHOR]

This article presents wheel wear in light rail traffic and the friction behavior of wheel material under both dry and lubricated conditions. The main purpose of this research is to study the wheel-rail tribology for the Addis Ababa Light Rail Transit and to evaluate the friction and wear behavior of the wheel material under both dry and lubricated conditions. Composition, hardness, and ring compression tests were conducted to characterize the existing and the developed material. The percentage composition of carbon, manganese, and silicon gained 0.5%, 0.7%, and 0.25%, respectively, for existing and 0.8%, 1.15%, and 0.38% for alloyed wheel steel. It is also shown that the hardness value of the wheel material increased from 98.88 to 99.7 HRC when the existing material is compared with the developed material. The samples with dimensions outer diameter of 42 mm, inner diameter of 21 mm, and height of 14 mm were used for this study, and the dimensional change occurring under ring compression is different depending on the dry and lubricant conditions. Based on experimental analysis, 0.15, 0.13, and 0.09 were the evaluated coefficients of friction for dry, grease, and oil conditions, respectively. It is concluded that 0.09 is a coefficient of friction and oil is a suitable lubricant. To minimize wheel wear in the wheel-rail, proper lubrication and better application, improved wheel material, and revised track alignment for easier cornering and improvement are required. [ABSTRACT FROM AUTHOR]

Ceramic coatings have much potential for steel tubulars' protection against high temperature corrosion of gases and liquids, often containing abrasive solid particles, and to enhance their integrity in severe power generation, mineral and oil & gas production environments. Combining self-propagating high-temperature synthesis (SHS) with high-speed centrifugal process, alumina-based coatings were produced onto the inner surface of tubulars for these applications. According to the developed SHS batch formulation and the designed centrifugal device and process, well-consolidated composite ceramic layers with a thickness of 1.5–3 mm have been obtained. The developed SHS process does not create hazardous gases, and it takes ∼30 s for the ceramic phase formation. A high-level compaction due to centrifugal forces and a liquid phase sintering approach provided a dense gradient ceramic structure formed by oxide grains cemented by a glassy phase and bonded with a steel substrate through a thin iron layer. The coatings were successfully produced onto the inner surface of carbon and stainless steels' tubes of up to 12 ft-lengths and standard dimensions from 2 to 3/8″ to 7.5" OD. The coatings were tested, for the first time, in wear and high-temperature corrosive environments, e.g., in steam–H 2 S–CO 2 gases and molten salts, with encouraging results due to high contents of Al 2 O 3 and some other oxides and consolidated ceramic structure. They can be recommended for applications in high-temperature (900 °C and greater) corrosive environments and erosive flows. [ABSTRACT FROM AUTHOR]

AlCoCrFeNiTi0.5 high entropy alloy (HEA) coating with high hardness and excellent wear resistance was deposited on TC4 surface by electron beam cladding, and the process parameters, microstructure and properties of the coating were studied. The analysis shows that the microstructure of HEA coating is composed of dendritic (DR) and interdendritic (IR) phases. The IR phase, which is mainly composed of Fe and Cr, is confirmed to be BCC solid solution, while the DR phase is FCC solid solution with AlNi2Ti (or AlCo2Ti) structure. The grain orientation of the HEA coating is random, without obvious texture. Hardness gradually decreases from the upper part area of the HEA coating to the inner of the TC4 substrate. The hardness curve in the HEA coating region has some fluctuations, but the fluctuations are small, indicating a homogeneous microstructure. The average hardness of the HEA coating is 796.18 HV0.2, which is about 2.6 times that of the TC4 substrate. The HEA coating exhibits a higher coefficient of friction (COF) compared to the TC4 substrate. The average COF of HEA coating and TC4 substrate in the stable stage are 0.57 and 0.48, respectively. Wear loss of the HEA coating is 0.0657 mm3, about one tenth of that of TC4 substrate (0.6112 mm3). The hardness of the HEA coating is high, no obvious furrow is found, and its wear mechanism is considered to be a mixture of adhesive wear and oxidation wear. [ABSTRACT FROM AUTHOR]

Based on the characteristics of octopus arm suction cup shape and distribution, a laser cylindrical texture with dimensions of R = 500 μm, W = 200 μm, and H = 50 μm was designed on the surface of G20CrMo substrate material using laser surface processing technology. The grooves of texture were filled with SnAgCu and comparative tests were respectively conducted under dry friction and grease lubrication conditions with a loading force of 10 N, reciprocating frequency of 1 Hz, and stroke of 8 mm. A comprehensive characterization and parameter analysis of wear scars were performed using various material surface analysis instruments. The experimental results showed that the cylindrical textured surface filled with SnAgCu reduced the friction coefficient by 22.9% compared to G20CrMo substrate surface under the dry friction condition. In addition, under the grease lubrication condition, although the cylindrical textured unfilled surface resulted in a higher friction coefficient, the friction coefficient and wear loss of cylindrical textured surface filled with SnAgCu were respectively reduced by 18.6% and 60% compared to those of G20CrMo substrate surface. [ABSTRACT FROM AUTHOR]

In this research work, Al matrix is reinforced with graphene, synthesized by the powder metallurgy method, and further processed by the hot extrusion process. The microstructure of aluminum and Al-graphene composite samples was investigated using FESEM and optical microscopy. The grain structure is investigated to analyze the grain size of pure aluminum and aluminum-graphene composites. Pin on Disk wear test setup is used to investigate the tribological behavior of the developed composites. Developed samples were tested experimentally to evaluate the influence of graphene addition, applied load, and sliding velocity on wear behavior. From the results, the wear rate of Al-Graphene composites is observed to be lower compared to monolithic aluminum samples. However, wear rate increases with the increase in velocity of sliding and the applied load. The Coefficient of Friction (COF) of composite samples was less than that of pure aluminum samples. Results reveal that the graphene-Al composites exhibit superior tribological properties during tribological tests and exhibit a 38.1% reduction in wear rate at a 60 N load. [ABSTRACT FROM AUTHOR]

The present work focuses on suggesting Gr as a valuable self-lubricating reinforcement for hybrid composite samples and offering a minimum wear rate for sliding pairs with fewer mechanical surface defects at the same time. A series of samples were fabricated using the route by stir casting method considering B4C and Gr as the two reinforcements. The morphology of the sample has been studied using the X-ray diffraction graphs, Energy dispersive X-ray analysis and Scanning electron imaging stating the homogeneity of reinforcement in various composite cast. The theoretical and experimental density of the series of samples has been studied and compared stating the low porosity of the samples fabricated. A maximum wear rate (Wr) of 0.351 × 10−4 mm3/m. was found for pure aluminium sample against EN31 steel disc with 0.053 as friction coefficient (µ). Wr was somehow seen to reduce up to 0.286 × 10−4 mm3/m for Al-B4C composite with µ of 0.48. For hybrid samples, the wear rate was further seen to improve to 0.187 × 10−4 mm3/m for Al-B4C and Gr 2.0% weight with µ of 0.38. Least Wr was found for composite having Gr 3.5% weight, of 0.149 × 10−4 mm3/m. with µ of 0.36. SEM images of the worn surface give evident results for delamination and crack formation on the pin face for the pure-Al sample. Taguchi-ANOVA analysis has been carried out showing the valid contribution of pin type, load and sliding speed on Wr and friction coefficient as the P-value lies below 0.05 for input parameters considering the 95% confidence level of the model developed. An F-value of 44.57 with R2 of 0.895 is developed for Wr model and an F-value of 54.2 with R2 of 0.934 for the µ model. [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]

In this study, the effects of hot dip aluminizing (HDA) (90 s at 725°C) and diffusion annealing on the microstructural and tribological properties of DP800 steel were investigated. After HDA treatment, one of the sample was left to cool in air (HDA-1) and the other one left to cool in air after being subjected to a diffusion annealing for 1 hour in an oven set at 300°C (HDA-2). Evolution in mechanical and tribological properties depending on the developments in the coating microstructure investigated in terms of hardness and wear behaviour, respectively. Mechanical characterization results show that diffusion annealing increases the hardness value of hot dip aluminized steel to 1100 HV values. Considering the wear ball volume and friction coefficients, the most advanced tribological properties were observed in the diffusion-annealed HDA process (HDA-2). [ABSTRACT FROM AUTHOR]

Most recently, metro rigid overhead wire-pantograph systems are subjected to severe wear of overhead wires and current collectors throughout China, which are difficult to completely solve up to now. The severe wear of metro rigid overhead wire-pantograph systems is probably brought about by the medium-high frequency vibration of the metro rigid overhead wire-pantograph systems. Coincidentally, corrugation is frequently found in rigid overhead wire systems, but rarely in flexible catenary systems. A frictional self-excited vibration model of a rigid overhead wire-pantograph system was set up. The self-excited vibration characteristics were investigated using the transient analysis and the motion stability analysis. Results show that when the friction coefficient is greater than 0.07, the rigid overhead wire-pantograph system is more prone to self-excited vibration. The self-excited vibration frequencies cover a range of 20–1000 Hz. The simulated overhead wire corrugation approaches the measured corrugation in wavelength. The influence factor analysis displays that the friction coefficient, zigzag layout of rigid catenary wires, and sliding direction of pantographs have significant effects on overhead wire corrugation, and but the train speed, normal force, main spring stiffness, and span of two positioning clips have a little effect. [ABSTRACT FROM AUTHOR]

This article explores the properties of composite materials employed in dental fillings. A traditional nano-hybrid composite containing nanofiller particles exceeding 82% by weight served as a benchmark. The remaining samples were fabricated from ormocer resin, maintaining an identical nanofiller content of 84%. In all specimens, the nanoparticles were dispersed randomly within the matrix. This study presents findings from investigations into surface geometry, hardness, wettability, and tribological behavior. The microscopic observations revealed that ormocer-based samples exhibited greater surface roughness than those composed of the traditional composite. Hardness testing indicated that both ceramic addition and sample preparation significantly influenced mechanical properties. Ceramic-enhanced samples demonstrated superior hardness, surpassing the reference composite by 30% and 43%, respectively. Contact angle measurements revealed hydrophilic characteristics in the classic composite, contrasting with the hydrophobic nature of ceramic-containing samples. Tribological evaluations revealed the superiority of the classic composite in terms of friction coefficients and volumetric wear compared to ormocer-based materials. [ABSTRACT FROM AUTHOR]

(1) Objectives: This study investigated and compared the wear and flexural strength of two highly filled (injectable), one flowable and one paste composite. (2) Methods: Two highly filled flowable composites (G-aenial Universal Injectable and Beautifil Plus F00), a paste composite (Empress Direct) and a conventional flowable (Tetric EvoFlow) were tested. A two-body wear test was carried out using 10 disc-shaped samples from each group, which were subjected to 200,000 wear machine cycles to simulate wear, followed by Scanning Electron Microscope analysis. Flexural strength was tested using a three-point bend test using 15 beam samples for each of the four groups. Values were statistically compared using one-way analysis of variance (ANOVA) for flexural strength and a Kruskal–Wallis test for wear. (3) Results: The median volume loss for G-aenial Universal Injectable and Beautifil Plus F00 was statistically lower than that of both Empress Direct and Tetric EvoFlow. For flexural strength the two highly filled flowable composites both exhibited statistically higher mean flexural strength values compared to Empress Direct (p < 0.004) and Tetric Evoflow (p < 0.001). There were no statistically significant differences in the values of wear and flexural strength between the two highly filled flowable composites. (4) Conclusions/significance: Highly filled flowable composite resins with nano filler particles outperformed a conventional flowable and a paste composite resin in terms of wear resistance and flexural strength, and may be suitable to use in occlusal, load-bearing areas. [ABSTRACT FROM AUTHOR]

In this study, for the first time, the optimization of applied pressure for achieving the one of the best tribological properties of diamond-like carbon (DLC) coating on graphite surface using plasma-enhanced chemical vapor deposition (PECVD) method was investigated. Raman spectroscopy and microscopy methods were used to characterize the applied coating. Additionally, the mechanical properties of the coating were investigated through nanoindentation testing. The wear resistance of coating has been tested as functional test. The results indicated that with increasing gas pressure, the sp3 hybridization percentage decreases, while the ID/IG ratio increases. The average roughness values for the uncoated sample and the coated samples at working pressures of 25, 30, and 35 mTorr were obtained as 1.6, 5.1, 3, and 2.4 nm, respectively. The results of hardness and wear tests showed that these properties were optimized by reducing the applied gas pressure. The highest hardness was 11.59 GPa, and the best sample in terms of the mechanical properties of the coating was the sample applied at a gas pressure of 25 mTorr. Results show that the optimal sample in tribological performance is the one applied at a working pressure of 25 mTorr. Because this sample demonstrates the lowest coefficient of friction, and wear depth. [ABSTRACT FROM AUTHOR]

This investigation employs the salt bath nitriding to extend the service life and improve the surface characteristics of AISI 52100, commonly employed in bearing applications. A wear test was conducted using a pin-on-disc device according to the ASTM G-99 standard, and the findings show a 30% reduction in wear loss. Sliding wear experiments were conducted at 1.5 m/s with a 5 N force at room temperature on uncoated and nitrided pins which was obtained as optimum value from RSM. The three variables and five levels of central composite design (CCD) were utilized to reduce the number of trials and the model relations were examined through ANOVA. Surface hardness, friction coefficient, wear coefficient, and loss in wear are measured over pins without coating and nitride pins. Investigations were done into how 5W30 oil affected passive and drip lubrication. Nitride substrates had a hardness of 590 HV. Also, nitriding has a favorable effect on the friction coefficient, lowering it by up to 23%. The 5W30 lubricant will further decrease the friction coefficient. The lowest friction coefficient was seen with the addition of 14% drip oil lubrication. Significantly less wear loss in the pin was caused by a combination of high hardness and low friction coefficient. [ABSTRACT FROM AUTHOR]

The present study adopts a multi-facet approach to design bio inspired concentrated alloys for potential application as articulating surfaces in joint replacements. A series of equiatomic, Nb rich and Ti rich TiMoNbZr based medium entropy alloys (MEAs) were processed via arc melting and their mechanical, in-vitro corrosion, wear, and in vitro and in vivo biocompatibility were investigated. Equiatomic MEA had primarily bcc with minor hcp phases where the single bcc was achieved with the addition of Nb. The single bcc Nb rich alloy resulted in 13 % elongation, much higher than equiatomic or Ti rich alloy. All the MEAs showed comparatively higher yield strength due to the climb of edge dislocations which is the main rate limiting mechanism at 300 K, as evident molecular dynamics (MD) simulation. The locally fluctuating energy landscape promotes kinks on edge dislocation, and at local minima nanoscale segments gets pinned. Upon yielding the entangled kink leaves a trail of vacancies/interstitials and escapes via climb motion to render high yield strength. The higher corrosion and pitting resistance of Nb enriched alloys can be attributed to the stable ZrO 2 , Nb 2 O 5 , TiO 2 , and MoO 3 oxides, high polarization resistance (106–105 Ωcm−2), and low defect densities (1016–1018). In vitro cell-materials interaction using MC3T3-E1 showed bioinert but cytocompatible nature of the MEAs. The wear rate of the MEAs was in the range of 7–9 × 10−5 mm3N−1m−1. The wear debris did not show any tissue necrosis when implanted in rabbit femur rather new bone regeneration can be seen around the particles. In the present work, a noble Nb enriched MEAs with superior mechanical, in vitro wear, corrosion and cytocompatibility properties was designed for articulating surfaces in joint replacement. • Single bcc in Nb enriched MEAs resulted in 13 % elongation with high hardness and yield strength. • Climb of entangled edge segment is the rate limiting mechanism in controlling high yield strength of MEAs at 300 K. • High polarization resistance (106–105 Ωcm−2), and low defect densities (1016–1018) attributes to ZrO 2 , Nb 2 O 5 , TiO 2 , and MoO 3 oxides enriched passive film. • Wet sliding wear rate ranged in order 7–9 × 10−5 mm3N−1m−1. In-situ generated wear debris when implanted in rabbit femur did not show any tissue necrosis rather new bone regeneration was observed around debris. [Display omitted] [ABSTRACT FROM AUTHOR]

The fracture strength was compared in a scratch test of coatings based on the ZrN system with the introduction of Ti, Nb and Hf, which were deposited on a titanium alloy substrate. The coatings were deposited using Controlled Accelerated Arc (CAA-PVD) technology. In coatings that simultaneously include Zr and Ti, a nanolayer structure is formed, while in coatings without Ti, the formation of a monolithic single-layer structure is observed. The comparison was carried out according to two parameters: adhesion strength to the substrate and overall coating strength. The (Zr,Hf)N coating showed better resistance to destruction, but had worse adhesion to the substrate. As a result, although the coating is retained directly in the scribing groove, a large area of delamination and destruction is formed around the groove. The (Ti,Zr,Nb)N coating, with its somewhat lower strength, has a high adhesion to the substrate; no noticeable delamination is observed along the groove boundary. In this paper, not only is the fracture resistance of various coatings deposited on a titanium alloy substrate compared, but the nature of this fracture is also investigated depending on the composition of the coatings. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

In this study, we investigated the mechanical and tribological properties of the layer-by-layer structure of additively manufactured implant-grade Polyether Ether Ketone (PEEK) through the Material Extrusion (ME) process as a potential substitute for artificial joints. The effective elasticity modulus of the anisotropic 3D-printed PEEK was determined to be 2.505 GPa along the vertical and horizontal build orientations. The lubricated friction and wear performance were assessed using a pin-on-disk test under various loads, including 14, 30, 50, and 70 N, with a sliding speed of 50 mm/s over a total distance of 1 km at 37 °C. The contact parameters between the hemispherical steel pin and 3D-printed PEEK disks, involving contact pressures over the circle of contact, were observed to increase as the load increased. The results indicated that the wear coefficient exhibited a rise from 1.418   ×   10 − 5 to 2.089   ×   10 − 1   as the applied loads increased, signaling a shift from mild to severe wear regimes. Fetal Bovine Serum (FBS) as a lubricant exhibited a mixed mechanism, ascertained through the Stribeck curve, as well as a minimum fluid film thickness of 1.346 nm under an isoviscous–elastic regime, as calculated by the maximum load. Moreover, the mechanism governing wear during sliding, influenced by both normal axial and shear loads, primarily involved adhesion. [ABSTRACT FROM AUTHOR]

Electric vehicles (EVs) continue to evolve, and sales continue to increase as the world pushes toward improved sustainability. This drives the need for research to understand the unique environments in which fluids operate within the Electric Drive Units (EDUs) of EVs in order to improve durability and reduce frictional losses. However, for this to happen, test rigs are required to operate with an electric current passing across the test parts and through the lubricant. Very few electrified test rigs currently exist, with most being adaptations of rigs undertaken by academia and independent and national research labs. In this work, the PCS Mini Traction Machine (MTM) was modified to supply a voltage across a tribological contact. New parts for the MTM were designed in collaboration with the instrument manufacturer. Work was undertaken in both the author's labs and the manufacturer's labs with the aim of bringing a commercially available unit to market as quickly as possible. A test matrix was completed on the MTM utilizing a range of temperatures, loads, and voltage inputs for three different lubricants commonly used in EDUs. The test matrix consisted of 36 test conditions, with some runs performed in triplicate, resulting in 81 tests for each oil and a total matrix of 243 tests. The test matrix was run to obtain the results and to test the robustness of the rig design. After testing was completed, the MTM disc wear scars were measured. The results from these measurements indicate that the application of alternating current (AC) and direct current (DC) causes a significant increase in the wear scar compared to non-electrified test conditions. This, in turn, results in increased traction values under non-electrified conditions. It was also noted that the repeatability of the traction curves and end-of-test wear was reduced under both AC and DC electrified conditions. [ABSTRACT FROM AUTHOR]

In this study, we analyze the extent to which thin hard coatings can serve as tribological protective layers for the selected plastic substrate materials PA12 (polyamide 12) und PEEK (polyetheretherketone), with and without fiber reinforcement. The approximately 1 µm thick coating variants ta-C, ta-C:N, and ta-C:B, which were applied using the laser arc process, are investigated. In oscillating sliding wear tests against a steel ball in an air atmosphere without lubricant, the wear of the coating and counter body is compared to analogous coating variants applied in parallel to AISI 52100 steel. The ta-C-based coatings show good adhesion strength and basic suitability as wear protection layers on the plastic substrates in the tribological tests. However, there are variations depending on the coating type and substrate material. The use of a Cr interlayer and its thickness also plays an important role. It is demonstrated that by coating under conditions where the uncoated plastic substrate would normally fail, a similarly good performance as with analogously coated steel substrates can be achieved by ta-C:N. [ABSTRACT FROM AUTHOR]

Improving the capabilities of online condition monitoring systems, able to detect arising of catastrophic wear on cutting tools, has been an important target to be pursued for the metal cutting industry. Currently, different systems have been proposed, moved by the rising need of part quality improvements and production cost control. Despite this, cutter wear development, being related to several process variables and conditions, is still really difficult to be predicted accurately. This paper presents a detection wear method based on the time-domain analysis of vibro-acoustic signals. Specifically, cutter wear monitoring, using sound signals of a milling process, was performed at a laboratory level in a well-isolated working room. Sound signals were recorded at fixed main machining parameters, i.e., cutting speed, feed rate and depth of cut. The tests were carried out starting with a new set of inserts with significant wear conditions for the investigated process configuration. Results showed a consistent overlapping between the beginning of the catastrophic wear and an evident increment in the trend of the root mean square of the monitored acoustic signal, showing the potential of the methodology in detecting a suitable time to stop the milling process and to change the worn-out cutters. [ABSTRACT FROM AUTHOR]

Reinforced PTFE materials can be designed to show high mechanical stability against harder materials under sliding wear conditions. Especially bearing metal-reinforced PTFE is of high practical interest. In this class of materials, bronze-filled PTFE was reported to obtain high wear resistance, a low coefficient of friction (COF), and excellent self-lubrication properties in sliding conditions. In the statistical approach of this work, PTFE composites reinforced with 25 vol%, 40 vol%, and 60 vol% bronze particles were evaluated against pure PTFE regarding wear behavior under varied wear test parameters, i.e., material, normal load, and sliding speed. Wear tests were planned to use a standard orthogonal array based on the Taguchi design method. An analysis of variance test was utilized to quantify the effects of test parameters on the wear behavior of the bronze/PTFE composites and pure PTFE. According to the variance analysis, the material type has the largest influence on the COF and the specific wear rate (SWR) under test conditions of this work. Both COF and SWR were found to be influenced by the material type (29.83% and 96.16%), the normal load (33.34% and 0.95%), and sliding speed (9.14% and 1.28%). The lowest SWR and COF values were achieved at the optimum wear test conditions where the wear test parameters were 1 m/s sliding speed (A4B2C2) at PTFE + 60 vol.% bronze reinforced composite 50 N application load and 0.32 m/s sliding speed (A4B3C1) at PTFE + 60 vol.% bronze reinforced composite 100 N application load, respectively. [ABSTRACT FROM AUTHOR]

The hard particles in the copper-based powder metallurgic material of a brake pad for a wind turbine brake falls off and presses into the surface of the brake disc to form abrasive particles under high-speed and heavy-load working conditions. The presence of abrasive particles will produce abrasive wear with micro-scratch and micro-scribe on the copper-based material of the brake pad. The critical scratch depth effect in the abrasive wear process is proposed based on the critical depth effect of the metal removal process at the micro-scale. The abrasive wear is divided into two types: scratch wear and scratch wear, which is proposed according to the comparison of the actual scratch depth and the critical scratch depth. The range of braking speeds and friction coefficients in abrasive wear is determined by the recommended parameters of the disc brake. The ABAQUS2020 software is used to simulate and analyze the micro-scale abrasive wear of a brake pad. The brake strain/stress curves of the brake pad under different brake speeds and friction coefficients are compared and analyzed for two abrasive wear types based on the range of braking parameters, and the key factors affecting abrasive wear are proposed. [ABSTRACT FROM AUTHOR]

This paper presents theoretical notions with practical applications for establishing the lifetime of a dental bur (durability and reliability) based on the wear of the active part and considering a series of statistical indicators. To justify applying theoretical notions in practice, a conical–cylindrical dental bur is studied experimentally to obtain a series of data of the work process necessary for statistical calculation. The parameter taken into consideration in this paper is mass lost through the wear of the dental bur active part, based on testing. This is useful for dental bur lifetime establishment and its extension or even optimization in operation. The loss of mass of the dental bur active part is analyzed in the work process using the results and experimental data obtained and validated by statistical–mathematical numerical calculation. The numerical calculation approximates the mass lost through wear at different rotation speeds and operation times, and based on a comparison with the experimentally determined ones, the lifetime was established. The results show that the dental bur works with high yield in the first 20 h of work, after which it should be replaced with a new one. Theoretically, the studied dental bur can work over 21 h. Practically, it can work up to 18 h without major risk of failure, but the lifetime can be extended up to 20 h, at which point the failure risk can reach 10% and it is recommended to replace the bur. [ABSTRACT FROM AUTHOR]

Blade wear is the critical problem in the operation of multiphase pump. This paper presents a numerical study of the multiphase flow of multiphase pump. The trajectory of particles in the pump is calculated by the discrete phase model. Then, the simulation results are compared with the model test results of the pump to verify the correctness of the simulation method. The results show that the particles in the impeller domain are mainly near the hub, and the particles in the diffuser domain form a agglomerated area in the middle of the flow channel. The average wear rate of the impeller is more affected by the particle size than that of the diffuser. The maximum wear rate of blade surface increases first and then decreases with the increase of particle size. According to the wear data under different particle sizes, the regression model between particle size and wear rate is fitted to predict the wear of mixed transport pump in actual operation. The research results have important reference value for the prediction of the wear performance of the multiphase pump. [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]

A self-lubricating coating is a kind of coating formed on the surface of the material by various processes that can self-replenish lubricating substances during the friction and wear process. This paper presents a comprehensive review of the processes and properties of self-lubricating ceramic coatings developed through Micro-arc Oxidation (MAO) on light alloys, including aluminum, magnesium, and titanium. Three technical approaches for the preparation of self-lubricating coatings via MAO are recapitulated. The structures and properties of the self-lubricating coatings prepared by each technical route are compared and analyzed, and the future development tendency of this field is also anticipated. [ABSTRACT FROM AUTHOR]

In this study, we demonstrated that adding 0.05 wt.% cellulose nanofibers (CNFs) to CNFpoly(methyl methacrylate) (PMMA) composite materials enhanced hardness, toughness, and maximum flexural strength, surpassing commercially available PMMA variants. Furthermore, CNF addition substantially improved PMMA's wear resistance, reducing wear volume through increased hardness and CNF's lubricating effect. The observed variation in slope in the wear volume versus dissipated energy plot suggests different wear mechanisms, and the potential to serve as a sensor for detecting wear interface behavior. [ABSTRACT FROM AUTHOR]

To improve the performance of laser cladding coatings, magnetic field-assisted laser cladding technology was combined with rare earth oxide Y2O3 to form composite laser cladding coatings on 300 M steel. The results of the experiment reveal that the magnetic field and Y2O3 had a magnetostrictive effect on the cladding coatings, and it had a significant impact on the lattice parameters. In the magnetic field, Y2O3 is beneficial to improve the uniformity of the element distribution and refine the grains, thereby improving the mechanical properties of the coatings. The effects of Y2O3 and the magnetic field on the wear and corrosion resistance of the cladding coatings were investigated through dry friction and electrochemical corrosion tests. The results revealed that the cladding coatings with a magnetic field and 3 wt.% Y2O3 had the best wear and corrosion resistance. The combined effect of the magnetic field and Y2O3 has a positive effect on the prevention of cracks and enhances the performance of the laser cladding coatings. [ABSTRACT FROM AUTHOR]

A 3-D printing method to produce dental prostheses of complex shapes from a commercial, photocurable resin-ceramic slurry is developed and optimized. The microstructure, mechanical properties and wear behavior of the resulting material are evaluated and compared with a conventional/control sample and other ceramic-polymer dental composites. Commercial resin-ceramic dental slurries can be successfully extruded and appropriately photocured in a low cost 3-D printing system to produce cost-efficient complex dental parts that could be used in indirect restorations. The printing process does not appreciably introduce defects in the material and the 3-D printed composites exhibit mechanical properties (hardness, elastic modulus) and wear resistance comparable to the control material and analogous, conventional dental composites. The main wear mechanisms under sliding contact against a hard antagonist are plastic deformation at the asperity level and ceramic particle pull-out due to filler/matrix interfacial weakness. [ABSTRACT FROM AUTHOR]

This study focuses on the production of functionally graded composites by utilizing magnesium matrix waste chips and cost-effective eggshell reinforcements through centrifugal casting. The wear behavior of the produced samples was thoroughly examined, considering a range of loads (5 N to 35 N), sliding speeds (0.5 m/s to 3.5 m/s), and sliding distances (500 m to 3500 m). The worn surfaces were carefully analyzed to gain insights into the underlying wear mechanisms. The results indicated successful eggshell particle integration in graded levels within the composite, enhancing hardness and wear resistance. In the outer zone, there was a 25.26% increase in hardness over the inner zone due to the particle gradient, with wear resistance improving by 19.8% compared to the inner zone. To predict the wear behavior, four distinct machine learning algorithms were employed, and their performance was compared using a limited dataset obtained from various test operations. The tree-based machine learning model surpassed the deep neural-based models in predicting the wear rate among the developed models. These models provide a fast and effective way to evaluate functionally graded magnesium composites reinforced with eggshell particles for specific applications, potentially decreasing the need for extensive additional tests. Notably, the LightGBM model exhibited the highest accuracy in predicting the testing set across the three zones. Finally, the study findings highlighted the viability of employing magnesium waste chips and eggshell particles in crafting functionally graded composites. This approach not only minimizes environmental impact through material repurposing but also offers a cost-effective means of utilizing these resources in creating functionally graded composites for automotive components that demand varying hardness and wear resistance properties across their surfaces, from outer to inner regions. [ABSTRACT FROM AUTHOR]

Alloyed high-carbon steels are materials primarily intended for components operating under conditions of intense tribological wear. The carbides present in the microstructure of these materials significantly contribute to improving the wear resistance of such alloys. However, changes in the morphology of these precipitates can considerably alter the wear rate, leading to a deterioration in the properties of the materials. Therefore, this study aims to analyze the influence of several factors on the tribological wear of alloyed high-carbon steel. The research included friction tests under various load conditions and different sliding paths. Additionally, the samples were subjected to heat treatment to change the morphology of the observed precipitates. The tribological tests were conducted in a block-on-ring configuration under dry friction conditions. The tribological tests were analyzed statistically using analysis of variance (ANOVA). The results of the statistical analysis indicated that the primary factor influencing the observed differences between the samples was the heat treatment time of the material. Additionally, there were no significant statistical differences when pressure and friction path were varied. These findings, in conjunction with the SEM studies, allowed for the evaluation of the wear mechanism. The results demonstrated that, within the adopted tribological system, no alterations in the wear mechanism were observed with changes in test parameters. The observed differences in wear properties between the samples were found to be related to their heat treatment. The heat treatment resulted in alterations to the particle size distribution, with the annealing of the material at an elevated temperature leading to the dissolution of finer particles within the material. An increase in the average diameter of the carbide present in the material was observed to improve the wear resistance of the alloy tested. [ABSTRACT FROM AUTHOR]

To explore wear-resistant and high-strength materials, Fe50Mn25Co10Cr10Ti5 high entropy alloy with non-equal atomic ratio was designed and prepared. The influence of annealing temperature on wear and mechanical properties was researched. The results show that the as-cast Fe50Mn25Co10Cr10Ti5 alloy presents hypereutectic microstructure which is composed of primary Laves phases and eutectic structure with FCC plus Laves phases. The main wear mechanism is contained fatigue wear, oxidation wear and abrasive wear. The microstructure and wear mechanism of the alloy have not changed significantly after annealing. With the increasing annealing temperature, the hardness and volume wear loss of the alloy present a tendency of going up first and then going down. The friction coefficient has not changed significantly after annealing 900 and 950 °C, while the alloy has increased significantly after annealing 1000 °C. In addition, the mechanical properties of Fe50Mn25Co10Cr10Ti5 alloy have not significantly improved after annealing 900 and 950 °C, while the compression rate and fracture strength have increased from 8.3 to 11.2% and 1493.2 to 1710.2 MPa, respectively, after annealing 1000 °C. The research results could provide experimental references to modify the wear and mechanical performance by using the annealing process. [ABSTRACT FROM AUTHOR]

In this study, properties of 316L SS coated with zirconium carbide (ZrC) incorporated Ti-6Al-4 V are discussed. Ti-6Al-4V-2ZrC coating is deposited on 316L SS by magnetron sputtering technique, and also coating morphologies were investigated using SEM, XRD, EDS and AFM. The coatings thickness of 4–5 µm shows dense structure with smooth and crack-free surface and improved surface roughness (Ra) of 0.03 µm. Nanohardness of coated 316L surfaces has been upgraded and showed maximum nanohardness of 14.31 GPa with the highest elastic modulus of 207 GPa. The wear behavior has been analyzed by applying a load of 2–3 N with a contact pressure of 78.56 MPa against E-52100 steel balls which shows improvement in resistance to plastic deformation. The presence of a Ti-6Al-4V-2ZrC layer on the surface of 316L steel has increased the tribocorrosion resistance by 1.2 times higher than the uncoated 316L steel. Scratch test results show the improved adhesion behavior. At an outset, due to its enhanced properties, Ti-6Al-4V-2ZrC-coated SS 316L is an excellent alternative and can replace artificial hip joints. [ABSTRACT FROM AUTHOR]

The present Bayesian network meta-analysis compared different types of polyethylene liners in total hip arthroplasty (THA) in terms of wear penetration (mm/year) and rate of revision. The type of liners compared were the crosslinked ultra-high molecular weight polyethylene (CPE/UHMWPE), Vitamin E infused highly cross-linked polyethylene (HXLPE-VEPE), modified cross-linked polyethylene (MXLPE), highly cross-linked polyethylene (HXLPE), Cross-linked polyethylene (XLPE). This study was conducted according to the PRISMA extension statement for reporting systematic reviews incorporating network meta-analyses of healthcare interventions. In June 2024, PubMed, Scopus, Embase, Google Scholar, and Cochrane databases were accessed. A time constraint was set from January 2000. All investigations which compared two or more types of polyethylene liners for THA were accessed. Only studies that clearly stated the nature of the liner were included. Data from 60 studies (37,352 THAs) were collected. 56% of patients were women. The mean age of patients was 60.0 ± 6.6 years, the mean BMI was 27.5 ± 2.0 kg/m2. The mean length of follow-up was 81.6 ± 44.4 months. Comparability was found at baseline between groups. XLPE and HXLPE liners in THA are associated with the lowest wear penetration (mm/year) and the lowest revision rate at approximately 7 years of follow-up. [ABSTRACT FROM AUTHOR]

In order to improve the wear and corrosion resistance of Ti6Al4V alloy, a Ti-N compound layer was formed on the alloy by plasma nitriding at a relatively low temperature (750 °C) and within an economical processing duration (4 h), in a mixture of NH3 and N2 gases with varying ratios. The influence of the gas mixture on the microstructure, phase composition, and properties of the Ti-N layer was investigated. The results indicated that the thickness of the nitrided layer achieved in a mixed atmosphere with optimal proportions of NH3 and N2 (with a ratio of 1:2) was substantially greater than that obtained in an atmosphere of pure NH3. This suggests that appropriately increasing the proportion of N2 in the nitriding atmosphere is beneficial for the growth of the nitrided layer. The experiments demonstrated that the formation of the surface nitrided layer significantly enhances the corrosion and wear resistance of the titanium alloys. [ABSTRACT FROM AUTHOR]

For space missions to either the Moon or Mars, protecting mechanical moving parts from the abrasive effects of prevailing surface dust is crucial. This paper compares the abrasive effects of two lunar and two Martian simulant regoliths using special pin-on-disc tests on a stainless steel/polytetrafluoroethylene (PTFE) sealing material pair. Due to the regolith particles entering the contact zone, a three-body abrasion mechanism took place. We found that friction coefficients stabilised between 0.2 and 0.4 for all simulants. Wear curves, surface roughness measurements, and microscopic images all suggest a significantly lower abrasion effect of the Martian regoliths than that of the lunar ones. It applies not only to steel surfaces but also to the PTFE pins. The dominant abrasive micro-mechanism of the disc surface is micro-ploughing in the case of all tests, while the transformation of the counterface is mixed. The surface of pin material is plastically transformed through micro-ploughing, while the material is removed through micro-cutting due to the slide over hard soil particles. [ABSTRACT FROM AUTHOR]

The primary characteristic of ablative materials is their fire resistance. This study explored the development of cost-effective ablative materials formed into application-specific shapes by using a polymer matrix reinforced with ceramic powder. A thermoplastic (polypropylene; PP) and a thermoset (polyester; UPE) matrix were used to manufacture ablative materials with 50 wt% silicon carbide (SiC) particles. The reference composites (50 wt% SiC) were compared to those with 1 and 3 wt% short glass fibers (0.5 mm length) and to composites using a 1 and 3 wt% glass fiber mesh. Fire resistance was tested using a butane flame (900 °C) and by measuring the transmitted heat with a thermocouple. Results showed that the type of polymer matrix (PP or UPE) did not influence fire resistance. Composites with short glass fibers had a fire-resistance time of 100 s, while those with glass fiber mesh tripled this resistance time. The novelty of this work lies in the exploration of a specific type of material with unique percentages of SiC not previously studied. The aim is to develop a low-cost coating for industrial warehouses that has improved fire-protective properties, maintains lower temperatures, and enhances the wear and impact resistance. [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]

The present work involves in a novel approach of studying the material characteristics of AZ31 alloy by varying the cooling method in powder metallurgy and particle size of the matrix material. It also has a novel approach of reinforcing AZ31 alloy with quarry dust and providing self oxide coating to the material in a distinct way for corrosion resistance. The alloy is prepared through powder metallurgy with a pressure of 675 MPa, sintered at 540 ºC, with one hour of soaking. The Scanning Electron Microscopy images are taken to analyse the microstructure. Wear and corrosion studies are done to analyse the effect of parameters. Optimisation for wear is also done with Taguchi method. The AZ31 samples reinforced 5, 10 and 15% of quarry dust are prepared and studied for mechanical properties. The material prepared using 75–150 micron range, cooled in still air cooling and with 5% reinforcement has shown higher values of compressive strength and microhardness. The alloy provided with self-oxide coating has shown higher resistance to corrosion than that of uncoated alloy and the composite. [ABSTRACT FROM AUTHOR]

In this study, tungsten–copper (W–Cu) composite was fabricated using the sintering process to examine the corrosion, wear and hardness of the fabricated samples at three different temperatures of 1050, 1150 and 1300 °C. The potentiodynamic polarization behavior of the composite samples was evaluated in 3.5% NaCl solution containing different benzotriazole inhibitors. Finally, the microstructure of the W–Cu composite was examined by SEM, TEM, XRD and EDS analyses. The XRD results on the milled samples showed that the optimal conditions were obtained with a ball to powder ratio of 16:1 and a milling time of 15 h, so that the crystals with a size of 16.76 nm were obtained. Also, the highest hardness (185 HV) and relative density (97.34%) were obtained in the samples sintered at 1300 °C. With increasing the wear force, the work hardening increased in the mechanically mixed layer, which led to a rise in the wear rate and a decrease in the friction coefficient. The corrosion behavior of the composite indicated that by addition of 200 ppm inhibitor in the corrosion solution, the corrosion current density decreased from 3.73 to 0.59 μA/cm2 and the corrosion potential improved from − 630.46 to − 336.28 mVSCE. [ABSTRACT FROM AUTHOR]

This study investigates the corrosion resistance and wear behaviour of aluminium matrix composites (AMCs) manufactured through the ultrasonic-assisted stir-casting technique. These composites were synthesized by introducing titanium carbide (TiC) and nickel (Ni) into aluminium alloys (AA6061). The X-ray diffraction results confirmed the presence of α-Al, TiC and Al3Ni phases within the composites. Microstructural examination demonstrated an uniform dispersion of TiC particles and dispersion of Al3Ni along grain boundaries. To evaluate the corrosion behaviour, samples were subjected to immersion tests and electrochemical techniques, including potentiodynamic polarization and electrochemical impedance spectroscopy (EIS), in a 3.5 wt% NaCl solution. Immersion tests indicated that the composites exhibited slower dissolution rates than base AA6061 alloys. Potentiodynamic polarization results revealed that the inclusion of TiC and Ni reinforcements enhanced corrosion resistance, with TiC having a more pronounced influence. The EIS tests suggested that the composites had higher charge-transfer resistance than AA6061 alloys. After conducting corrosion tests, scanning electron microscope (SEM) images of the base AA6061 alloys unveiled the presence of deep pits but the inclusion of reinforcements resulted in the shallow pits. In addition, Vickers hardness tests and pin-on-disc wear tests were conducted to investigate hardness and wear properties. Notably, hybrid composites containing 3% TiC and 3% Ni exhibited a substantial 42.18% increase in hardness as compared to the base alloy. These hybrid composites also demonstrated superior wear resistance, with a wear rate that was 58.6% lower compared to AA6061 alloy and 41% less than that of the 3% Ni-reinforced composite. [ABSTRACT FROM AUTHOR]

Wear caused by friction is one of the main causes of most mechanical component failures. The application of powders as anti-wear lubricating materials has achieved great advances, which are of great significance in reducing friction and wear. This review focuses on the applications of phyllosilicates mineral powders as anti-wear lubricating materials in lubricating oil. The tribological behaviors of phyllosilicates mineral powders and the combination of phyllosilicates mineral powders with other materials as lubricant additives are provided. Moreover, the fundamental mechanism are systematically reviewed and concluded based on tribology data and surface, and interface analysis. Finally, current unsolved issues and suggestions for future research on phyllosilicates mineral powders as lubricant additives are proposed. [ABSTRACT FROM AUTHOR]

In this study, MoS2 nanosheets have been prepared and treated ultrasonically with silver ammonia solutions. The MoS2/Ag precursor was reduced using dopamine (DA) as reducing and linking agent at room temperature, and it was subjected to a hydrothermal treatment to produce MoS2/Ag nanocomposites (denoted as MoAg). The MoAg samples were functionalized with N-oleoylethanolamine to improve dispersion in the base oil component of additives. Use of the functionalized MoAg (denoted as Fc-MoAg) as a lubricant additive for steel balls resulted in effective friction reduction and anti-wear. This work avoids ion exchange during exfoliation, and the Ag+ has been reduced to nano-silver particles by dopamine to enlarge the layer spaces of MoS2. Taking the case of lubrication with base oil containing Fc-Mo0.6Ag15, the wear scar diameters and coefficients of friction of the steel balls were 0.428 and 0.098 mm, respectively, which were about three-fifths base oil. In addition, MoS2/Cu and MoS2/Ni nanocomposites were synthesized and the tribological properties associated with steel/steel balls assessed. The results demonstrate that all MoS2/metal composites exhibit enhanced tribological behavior in the steel/steel pair tests. Both nanocomposite synergy and the tribofilm containing sulfide, oxide, carbide, and other compounds play important roles in achieving reduced friction and improved anti-wear. The friction and wear properties of base oil containing Fc-MoAg and commercial additives were evaluated using a four-ball wear tester with steel/steel, steel/zirconia and zirconia/zirconia pairs. The base oil containing Fc-MoAg delivered smaller coefficients of friction (COFs) and/or scarring groove depths than those observed with the use of pure base oil and base oil containing commercial additives. [ABSTRACT FROM AUTHOR]