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To safeguard materials against abrasive corrosion, various thermal spraying techniques can be employed, including powder spraying with a gas flame, plasma spraying, deposition and melting, highspeed oxygen-gas spraying, and detonation spraying. Thermal spraying is highly effective for protecting materials from wear and corrosion, thus extending their service life. This article discusses the changes in the surface of Ni-Cr-Al coatings subjected to pulsed plasma treatment using a plasma generator. The coatings were initially applied via detonation spraying (DS) and then underwent pulsed plasma treatment (PPT). The study investigates alterations in the structural and phase states of the coatings under plasma exposure. A comprehensive analysis of the detonation Ni-Cr-Al coatings' characteristics was conducted using scanning electron microscopy (SEM), X-ray energy dispersive spectroscopy (EDX), X-ray diffraction (XRD), surface roughness measurements, hardness tests, and tribological assessments. The findings indicate that pulsed plasma treatment enhances the wear resistance of the coatings' surface layer by reducing the coefficient of friction and increasing microhardness. X-ray phase analysis reveals that the improved tribomechanical properties of the treated surfaces are linked to an increased presence of CrNi3, NiAl, and NiCr phases in the coatings. [ABSTRACT FROM AUTHOR]

Silicate drilling fluids have strong inhibitive capacity and good environment protection property, but their poor lubricity limits their application. In screening good lubricating agents for silicate drilling fluids, extreme pressure (EP) lubrication tester is used to measure the coefficient of friction of silicate drilling fluid samples containing amphiphilic carbon dots and polyoxyethylene surfactant. The best lubricating agent selected is then tested with total organic carbon analyzer, dynamic light scattering tester and contact angle tester to analyze its mechanisms of lubrication. The test results show that the amphiphilic cardon dots have excellent lubricity and high temperature stability. A 5% sodium silicate (Na2SiO3 ) water solution treated has EP coefficient of friction of around 0.500. The solution is then treated with 0.3% amphiphilic carbon dots (C12-CDs), and the EP coefficient of friction is reduced to 0.065. After hot rolling the C12-CDs treated Na2SiO3 solution at 110 ℃ for 16 h, the EP coefficient of friction of the solution is further reduced to 0.063, that is, the EP coefficient of friction of the Na2SiO3 solution is reduced by 87.52%. On the other hand, the polyoxyethylene surfactant shows no effect on the lubricity of the Na2SiO3 solution. Further study shows that C12-CDs has excellent adsorption performance on the surface of the quartz sands, the surface tension of a C12-CDs solution (c = 100 mg/L) increases from 44.81 mN/m before the adsorption process to 64.03 mN/m after the adsorption process, the adsorption capacity is 89.23 mg/L. Particle size analysis shows that the C12-CDs can effectively reduce the particle sizes of the Na2SiO3 solution; the average particle size of the Na2SiO3 solution is reduced from 514 nm to 63.2 nm. The multi-hydroxy structure and the long hydrophobic chain on the surface of the carbon nuclei can improve the adsorption of the amphiphilic carbon dots on the surfaces of the drill string, the borehole walls and the silicate aggregates. The amphiphilic carbon dots as a good lubricating agent have good compatibility with silicate drilling fluids. Field application shows that C12-CDs can reduce the coefficient of friction of silicate drilling fluids by 86.34%, and are thus a good lubricating agent for silicate drilling fluids. [ABSTRACT FROM AUTHOR]

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

Copyright of FME Transactions is the property of University of Belgrade, Faculty of Mechanical Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The study explored the viability of using waste plastic oil (PO) as an alternative lubricant to petroleum-based lubricants in industrial settings. To enhance the lubrication performance of the PO, this study incorporated cost-efficient, oleic acid-modified, graphene nano platelets [GNP (f)] and hexagonal boron nitride [hBN (f)] nano solid lubricant additives into the PO in various concentrations, forming functionalized nano lubricants. The PO and its functionalized nano lubricant's rheological, dispersion stability, thermal degradation, friction, and wear performance were investigated. Results manifest that incorporating GNP (f) and hBN (f) into the PO significantly enhanced the viscosity and dispersion stability. In addition, it was seen that GNP (f) and hBN (f) nano lubricants lowered the coefficient of friction (COF) by 53% and 63.63% respectively, compared to the PO. However, the GNP (f) and hBN (f) nano lubricants demonstrated a 3.16% decrease and a 50.08% increase in wear volume relative to the PO. Overall, the GNP (f) and hBN (f) nano lubricants displayed a synergistic friction behavior, while they exhibited an antagonistic behavior pertaining to the wear volume. The study elucidated the mechanisms underlying friction and wear performance of the nano lubricants. [ABSTRACT FROM AUTHOR]

Copyright of Ingenius, Revista Ciencia y Tecnología is the property of Universidad Politecnica Salesiana and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The present study focusses on friction-induced noise arising during steel-on-steel sliding under sesame grease lubrication. The effect of sliding frequency (10 Hz, 20 Hz, and 30 Hz) and load (10 N, 20 N, and 30 N) on the frictional noise was studied. Taguchi's L18 orthogonal array was utilized to design experiments and a ball-on-disc configuration of tribo-setup was used to carry out friction experiments with EN31 steel ball and disc. Taguchi's S/N ratio analysis of the obtained experimental results was carried out for optimization of parameters. TOPSIS method was utilized for multiple objective optimization of response variables, viz., average frictional noise and average coefficient of friction (COF). Furthermore, the analysis of variance (ANOVA) technique was used to check the influence of input control variables on the response variables. In order to understand the wear mechanisms, the worn surfaces were analyzed using FESEM and EDS. The results revealed that employing sesame grease at the interface of steel-on-steel tribo-pair significantly reduces both average frictional noise and average friction coefficient compared to dry sliding conditions. The experimental control factor setting of load, 20 N, frequency, 10 Hz, and test condition, grease-lubricated, offers optimal results for both average frictional noise and average friction coefficient optimized together. [ABSTRACT FROM AUTHOR]

In this investigation, a duplex surface modification of M2 high-speed steel (HSS) was demonstrated, including electron beam treatment (EBT) followed by a tungsten nitride (WN) coating deposition. The influence of the EBT of the substrate on the functional properties of the film was also studied. The phase composition of the EBT sample consists of Fe (the main element in the M2 HSS), as well as MC and M6C carbides, while the phase composition of the EBT + WN sample consists of the α'-Fe, M6C, and WN phases. The depth of the treated zone is about 20 μm, and the thickness of the WN coating is about 300 nm in all cases. The hardness of the coating deposited on the EBT substrate is 12.4 GPa, while that of the WN film deposited on the untreated substrate is 8.8 GPa. The application of the electron beam treatment procedure and deposition of WN film leads to an improvement in the tribological properties where the coefficient of friction decreases from 0.81 to 0.66. However, the same coating deposited on untreated substrate exhibits even less friction coefficient values of 0.54. The applied modification technique suggests that this is a viable method for improving the mechanical and tribological properties of the surface of tool steels and, thus, their longevity and applicability. [ABSTRACT FROM AUTHOR]

The current investigation delved into the friction and wear characteristics of abrasive-finished Inconel 718 alloys fabricated by additive manufacturing and casting methods. Silicon carbide balls were used as counter-body materials for all tribology tests. Variable loads of 10 N, 20 N, and 30 N were applied, along with frequencies of 5 Hz and 15 Hz, while maintaining a 1 mm stroke length for 30 min. Cast samples showed an increase in coefficient of friction (COF) when the load increased from 10 to 20 N at 5 Hz. COF value was decreased from 0.28 to 0.25 when the load was increased from 20 to 30 N while the frequency was maintained at 5 Hz. At the same frequency of 5 Hz, additively manufactured samples displayed a constant increase in COF from 0.19 to 0.35 as the load increased from 10 to 30 N. Consistent COF values were determined at 15 Hz for cast and additively manufactured samples. The COF for cast samples at a frequency of 15 Hz was 0.26, 0.25, and 0.25 for loads of 10 N, 20 N, and 30 N, respectively. For the same loads and frequencies, COF values of 0.23, 0.24, and 0.24 were reported in additively manufactured samples. At 15 Hz, both cast (7.25 × 10–6 mm3/N.m to 9.91 × 10–6 mm3/N.m) and additively manufactured (5.80 × 10–6 mm3/N.m to 6.18 × 10–6 mm3/N.m) samples exhibited constant increasing trends of specific wear rates when the loads increased from 10 to 30 N. [ABSTRACT FROM AUTHOR]

Cigarettes with pronounced astringency can diminish consumers' enjoyment. However, due to the complex composition of cigarettes, quantifying astringency intensity accurately has been challenging. To address this, research was conducted to develop a method for assessing astringency intensity in a simulated oral environment. The astringency intensity of four cigarette brands was determined using the standard sensory evaluation method. The mainstream smoke absorbing solution (MS) was prepared by simulating the cigarette smoking process, and its physicochemical properties (such as total phenol content and pH levels) were analyzed. The lubrication properties of the five solutions were tested using the MFT‐5000 wear tester, and factors influencing cigarette astringency were examined. The findings showed that total phenol content and pH of MS were positively and negatively correlated with astringency intensity, respectively. Particularly, the lubrication properties of MS were significantly correlated with astringency intensity, and the correlation coefficient was affected by load and speed during testing. The study concluded that coefficient of friction was a more reliable measure for assessing the extent of astringency in cigarettes than the total phenol content and pH of MS, offering new insights into astringency evaluation and development of high‐grade cigarettes. [ABSTRACT FROM AUTHOR]

Single-phase (Dy 0.2 Ho 0.2 Er 0.2 Tm 0.2 Lu 0.2)B 12 high-entropy dodecaboride (HEDB) is synthesized by reactive spark plasma sintering, and its tribological and wear-resisting properties under different conditions are studied systematically using the ball-on-disk technique with the Al 2 O 3 and Gcr15 balls. These friction tests indicate that the whole wear process undergoes three discernable stages. The friction coefficients exhibit erratic variations and cyclic fluctuations during the running-in and stable periods, respectively, and there is a slight reduction during the severe wear period. Most remarkable is that the volume wear rates are much lower than that of the constituent binary dodecaborides and even a few orders of magnitude smaller than that of common anti-wear materials such as SiO 2 , hinting that the HEDB ceramic is a high wear-resistant material. The microstructural analysis shows that the fatigue wear of the HEDB arises from the combined action of surface and subsurface cracks, which conforms well to the delamination theory of wear. [ABSTRACT FROM AUTHOR]

This article presents the results of pilot studies on the lubrication of the blankholder zone in sheet metal forming using a pressurised lubricant. The authors invented a method and built a special tribometer for pressure-assisted lubrication. This approach reduces friction in sheet metal forming processes compared to conventional lubrication. Moreover, the artificial neural network approach combined with a force-directed Fruchterman-Reingold graph algorithm and Spearman's correlation was used for the first time to analyse the relationships between the friction process parameters and the output parameters (the coefficient of friction and the resulting surface roughness of the sheet metal). The experimental tests were conducted utilising strip drawing on four grades of steel sheets known to be outstanding for deep-drawing quality. Different oils, oil pressures and contact pressures were used. Artificial neural network models were used for the first time to determine these relationships in a strip drawing test where every parameter is represented by one node, and all nodes are connected by edges with each other. R Software version 4.2.3 was used to construct the network using the 'qgraph' and 'networktools' packages. It was found that friction conditions had a highly significant negative correlation with coefficient of friction (COF) and a moderately significant negative correlation with the final surface roughness. However, the initial surface roughness of the as-received sheets had a negative correlation with the COF and a positive one with the resulting surface roughness of the sheet metal. The parameters most related to the COF are the strength coefficient, the ultimate tensile strength and the friction conditions (dry friction or pressurised lubrication). Spearman's correlation coefficients showed a strong correlation between the kinematic viscosity and the friction conditions. [ABSTRACT FROM AUTHOR]

The research on friction and chemical behavior in CMP process is reviewed. The relevant articles are mainly divided into three aspects: Experimental study on the effect of chemical components in polishing fluid on the tribological lubrication state of wafer, molecular dynamics simulation of the reaction between polishing fluid components and wafer surface materials in しMP process and molecular dynamics simulation of reaction force field, CMP material removal rate model considering both tribological lubrication and chemical reaction. The mechanism of mechanical and chemical synergies in CMP process is still unclear, considering the synergies between mechanical friction and chemical reaction is one of the important research directions to improve the theoretical framework of CMP in the future. [ABSTRACT FROM AUTHOR]

The role of industrial lubricants in machinery is to reduce friction and wear between moving components. Due to the United Nations' tendency to reduce dependency on fossil fuel, a general awareness is strongly driven towards developing more eco-friendly lubricants. Palm oil possesses promising properties, which promote it to be a competitive alternative to the hostile mineral oils. Still, marginal oxidation stability, viscosity, and tribological properties remain critical issues for performance improvement. This paper presents an improved palm grease using reduced graphene oxide (rGO) and zinc oxide (ZnO) nano-additives at different concentrations. Oil and grease samples were tested for viscosity, oxidation stability, pour point, penetration, roll stability, dropping point, churned grease-oil release, copper corrosion, friction, and wear. ZnO additives enhanced the oxidation stability by 60% and shifted the pour point to 6 °C. Adding ZnO and rGO to the palm grease increased the load-carrying capacity between 30% and 60%, respectively, and reduced the friction coefficient by up to 60%. From the wear scar morphologies, it is believed that graphene 2D nanoparticles formed absorption layers which contributed to the increase in load-carrying capacity, while ZnO chemically reacted with the metallic surface layer, forming zinc compounds that resulted in a protective boundary lubricating film. [ABSTRACT FROM AUTHOR]

This study investigates the tribological properties of an AA 5754 aluminum alloy composite reinforced with the nanopowder of Al2O3, fabricated using the friction stir processing (FSP) technique with blind holes. The aim is to analyze the effects of varying the tool rotational speed (rpm) and blind hole diameter on the wear and friction behavior of the produced composite. A pin-on disk test is conducted under dry conditions and room temperature to assess the tribological properties against steel. Scanning electron microscopy (SEM) coupled with energy dispersive X-ray spectroscopy (EDS) is employed to examine the worn and wear surfaces of the produced composites post test. The results indicate that increasing the applied load results in a decrease in the coefficient of friction (COF), with values ranging from 0.775 to 0.852 for 10 N and 0.607 to 0.652 for 20 N. Moreover, the wear rate diminishes with higher Al2O3 content and optimal FSP tool rotation (1280 rpm). Hardness analysis reveals variations between 33–42 HV and 35–39 HV, influenced by nanoparticle distribution. The composite demonstrates superior wear resistance compared to raw AA5754 aluminum due to its reinforced nature. However, high FSP tool rotation rates lead to abrasive wear and surface cracks. These findings offer insights into optimizing FSP parameters to enhance the tribological performance of nano-reinforced aluminum alloys. [ABSTRACT FROM AUTHOR]

The processes occurring on the contact surface during friction of experimental carbon–carbon composite materials reinforced with a carbon fabric based on polyacrylonitrile (PAN) and a viscose precursor were studied. Tribological tests of the composites were carried out on a tribometer using a ring–disk contact scheme. Two materials were used as counterbodies: hardened steel and silicon carbide ceramics. It has been established that the wear rate and friction coefficient under the load-speed modes used in operation mainly depend on the choice of the counterbody material. Heat treatment (carbonization or graphitization) and precursor material (PAN or viscose) also have an effect, but depending on the selected counterbody. It is shown that when tested with a ceramic counterbody, the tribological characteristics (friction coefficient and wear resistance) are better compared to friction paired with a steel counterbody. The surfaces of counterbodies and composites were studied before and after tribological tests by scanning electron microscopy, X-ray spectral analysis, and optical profilometry. It is shown that during friction a film of secondary structures is formed on the surface of carbon composites from wear products. This is the determining factor that affects tribological characteristics. After testing with a steel counterbody, a significant amount of iron was found on the surface of the composites in the film, which indicated wear of the counterbody. This process negatively affects the tribological properties of the composites. At the same time, the ceramic counterbody practically does not wear out, which makes it a more preferable material for working in friction units paired with a carbon composite. [ABSTRACT FROM AUTHOR]

Laser surface texturing (LST) with different patterns was performed on silicon nitride (Si3N4) ceramic. Effect of patterns created by LST on coefficient of friction (COF) and surface damage under dry friction was investigated. Results indicated that fluctuation of COF decreased with the increasing loading force for both un-textured and textured samples. Under the same loading force, COF of Si3N4 ceramic with textured patterns was more stable than the samples with smoothly finished surface. The COF of textured samples was not always lower than that of un-textured samples. This may be caused by differences in the distribution of debris and the continuity of surface contact. The worn surface existed damages of plow and crack. However, peeling was observed on un-textured samples only. The surface damage of textured samples was slighter than un-textured samples. Especially under the high loading force, catastrophic damage appeared on the smooth surface. The worn surface of textured samples still maintained the similar state. This could be mainly due to the more complex friction process on the surface of textured sample. The wear rate of the frictional pair was also studied. The mechanisms of friction process for smooth and textured surface were analyzed. [ABSTRACT FROM AUTHOR]

This study employs the finite element (FE) method to analyze the Incremental Sheet Forming (ISF) process of Ti-6Al-4V titanium alloy. The numerical modeling of pressure-assisted warm forming of Ti-6Al-4V sheets with combined oil-heating and friction stir rotation-assisted heating of the workpiece is presented in this article. The thermo-mechanical FE-based numerical model took into account the characteristics of the mechanical properties of the sheet along with the temperature. The experimental conditions were replicated in FEM simulations conducted in Abaqus/Explicit, which incorporated boundary conditions and evaluated various mesh sizes for enhanced accuracy and efficiency. The simulation outcomes were compared with actual experimental results to validate the FE-based model's predictive capacity. The maximum temperature of the tool measured using infrared camera was approximately 326 °C. Different mesh sizes were considered. The results of FEM modeling were experimentally validated based on axial forming force and thickness distribution measured using the ARGUS optical measuring system for non-contact acquisition of deformations. The greatest agreement between FEM results and the experimental result of the axial component of forming force was obtained for finite elements with a size of 1 mm. The maximum values of the axial component of forming force determined experimentally and numerically differ by approximately 8%. The variations of the forming force components and thickness distribution predicted by FEM are in good agreement with experimental measurements. The numerical model overestimated the wall thickness with an error of approximately 5%. By focusing on the heating techniques applied to Ti-6Al-4V titanium alloy sheet, this comparative analysis underlines the adaptability and precision of numerical analysis applied in modeling advanced manufacturing processes. [ABSTRACT FROM AUTHOR]

In the present investigation, an Al-18Si-3.6Cu alloy was modified by cerium (Ce), heat treated (T6), and aged for 1, 3, 5, and 7 h at 210°C. The resulting microstructures revealed that the addition of Ce as a modifier changed the morphology of the primary Si from coarse with a sharp edge to spherical, large-acicular/needle-like eutectic Si into a fibrous state, and dendrites of the Al phase into round branches with less interface separation. After thermal ageing, the microstructure of the modified alloy revealed no change in the morphology of the primary Si phase. However, a considerable change in the eutectic Si phase and the formation of fine precipitates of Al2Cu and Al2CeSi intermetallics in the matrix. Hardness was found to be significantly higher in the modified and age-hardened alloys. A Pin-on-disc wear tester was used to investigate the dry sliding wear behavior of alloys at different loads (10, 20, 30, and 40 N) and 1.0 m/s sliding velocity. The results indicated that the wear rate in the modified alloy was lower than the base alloy. Furthermore, the modified alloy after 5 h age hardening demonstrated high wear resistance and improved wear bearing capacity compared to the 1, 3, and 7 h age hardened alloys. [ABSTRACT FROM AUTHOR]

This novel experimental work aims to bring further knowledge of frictional performance of common barrier products used in the treatment of incontinence-associated dermatitis and determine how the skin-pad interface changes when a treatment is applied to the skin. Key data is reported and there is an in-depth analysis into friction profiles which reveals great differences between how different skin-pad tribosystems operate when exposed to commercially available barrier treatments. In a wet-pad state Barrier cream A (3M™ Cavilon™ Barrier cream) reduced friction and had much lower dynamic and static coefficients of friction than the other barrier treatments (Barrier cream B (Sorbaderm Barrier cream) and the Barrier spray C (Sorbaderm Barrier spray)). Barrier cream A provided stable friction coefficients in reciprocating sliding, whereas the other treatments, and untreated skin, did not display this unique characteristic. The barrier spray gave rise to high static friction coefficients and exhibited the most stick-slip. All three candidate barrier protection products were found to reduce directional differences in the static coefficient of friction: indicative of reduced shear loading. Knowledge of the desirable frictional properties would drive innovation in product development, and benefit companies, clinicians and users. [ABSTRACT FROM AUTHOR]

This study explores, through a full factorial experimental design, the effects of graphite concentration and spray flow rate on the morphology, thickness, and tribological performance of graphite coatings for potential tribological applications. Coatings were applied to rough substrates using varying concentrations and flow rates, followed by analysis of their morphological characteristics, roughness, thickness, coefficient of friction (COF), and wear behavior. The results revealed distinct differences in the coating morphology based on flow rate, with low-flow-rate coatings exhibiting a porous structure and higher roughness, while high-flow-rate coatings displayed denser structures with lower roughness. A COF as low as 0.09 was achieved, which represented an 86% reduction compared to uncoated steel. COF and wear track measurements showed that thickness was influential in determining friction and the extent of wear. Flow rate dictated the coating structure, quantity of transfer film on the ball, and the extent of graphite compaction in the wear track to provide a protective layer. SEM and elemental analysis further revealed that graphite coatings provided effective protection against wear, with graphite remaining embedded in the innermost crevices of the wear track. Low flow rates may be preferable for applications requiring higher roughness and porosity, while high flow rates offer advantages in achieving denser coatings and better wear resistance. Overall, this study highlights the importance of optimizing graphite concentration and spray flow rate to tailor coating morphology, thickness, and tribological performance for practical applications. [ABSTRACT FROM AUTHOR]

Titanium (Ti) alloys have been widely used in biomedical applications due to their superior mechanical, physical, and surface properties, while improving their tribological properties is critical to widening their biomedical applications in the current era. The present review examines the recent progress made in enhancing the tribological performance of titanium alloys and titanium matrix composites for biomedical purposes. It specifically focuses on the progress made in biomedical coatings, mechanical surface treatment, and developing titanium matrix composites in terms of their processing, tribological testing conditions, and characterization. Despite thorough investigations, the specific testing procedures for evaluating the friction and wear properties of the alloy and/or biomedical component are still uncertain. The majority of researchers have selected test methods and parameters based on previous studies or their own knowledge, but there is a scarcity of studies that incorporate limb-specific tribological tests that consider the distinct kinematic and biological structure of human limbs. Since advanced microscopy has great potential in this field, a variety of advanced characterization techniques have been used to reveal the relationship between microstructural and tribological properties. Many coating-based strategies have been developed using anodizing, PEO, VD, PVD, nitriding, thermal spray, sol-gel, and laser cladding, however; composition and processing parameters are crucial to improving tribological behaviour. Reinforcing component type, amount, and distribution has dominated Ti matrix composite research. Ti grade 2 and Ti6Al4V alloy has been the most widely used matrix, while various reinforcements, including TiC, Al2O3, TiB, hydroxyapatite, Si3N4, NbC, ZrO2 have been incorporated to enhance tribological performance of Ti matrix. Mechanical surface treatments improve biomedical Ti alloys’ tribological performance, which is advantageous due to their ease of application. The implementation of machine learning methods, such as artificial neural networks, regression, and fuzzy logic, is anticipated to make a substantial contribution to the field due to their ability to provide cost-effective and accurate results. The microstructural and surface features of biomedical Ti alloys directly affect their tribological properties, so image processing strategies using deep learning can help researchers optimize these properties for optimal performance.

Dental restoration has been a major concern of healthcare since centuries. Several alloys are in use for dental prostheses including Ni–Cr–Mo alloy. The Ni–Cr–Mo alloy has advantage of economy and density over other alloys, while possessing equivalent corrosion and biocompatibility characteristics. However, beryllium in Ni–Cr–Mo dental casting alloys has associated health hazards, being carcinogenic. In this research Ni–Cr–Mo alloys with minor additions of boron (0.2 wt %), cerium (0.4 wt %) and titanium (2 wt %), to replace beryllium were developed through vacuum induction melting and investment casting technique. Manufacturing steps are detailed for the alloy development to have medically clean alloy, suitable for biomedical applications. The cast alloy samples were tested for microstructure, phases, melting temperatures, wear and corrosion characteristics. Corrosion and wear test results demonstrate that the composition with minor addition of cerium had a significant effect to have low corrosion rate (25.92 × 10−3 mills per year), low wear rate (0.04 × 10−4 mm3/N.m) and lowest coefficient of friction.

ABSTRACTLaser surface texturing (LST) with different patterns was performed on silicon nitride (Si3N4) ceramic. Effect of patterns created by LST on coefficient of friction (COF) and surface damage under dry friction was investigated. Results indicated that fluctuation of COF decreased with the increasing loading force for both un-textured and textured samples. Under the same loading force, COF of Si3N4 ceramic with textured patterns was more stable than the samples with smoothly finished surface. The COF of textured samples was not always lower than that of un-textured samples. This may be caused by differences in the distribution of debris and the continuity of surface contact. The worn surface existed damages of plow and crack. However, peeling was observed on un-textured samples only. The surface damage of textured samples was slighter than un-textured samples. Especially under the high loading force, catastrophic damage appeared on the smooth surface. The worn surface of textured samples still maintained the similar state. This could be mainly due to the more complex friction process on the surface of textured sample. The wear rate of the frictional pair was also studied. The mechanisms of friction process for smooth and textured surface were analyzed.

This paper presents the results of experimental tests of the efficiency of a single-stage worm gear. Two worm drives were used for testing, where the worms are made of improved steel 42CrMo4 and the worm gears are made of tin bronze CuSn12 and aluminium alloy A356. The values of the efficiency were determined at different values of revolutions and loads, where oils of different viscosities were used for lubrication. Determining the efficiency, the coefficient of friction of worm drives was calculated for experimental operating conditions, as well as the mass measurement of worm gears before and after testing. Based on the experimental results, depending on the operating mode and oil viscosity, the values of the efficiency of the worm drive made of the material 42CrMo4/CuSn12 are higher by 5 to 9 % compared to the worm drive 42CrMo4/A356. Higher values of the efficiency of the worm drive 42CrMo4/CuSn12 cause lower values of the coefficient of friction by 14 to 21 % as well as less wear of the worm gears.

In today’s paradigm petroleum and petro-based chemical products are being extracted and consumed at a substantial rate, proving to be hazardous and detrimental to the earth. Bio based resources are environmentally friendly, energy efficient, economical, and proved to be an alternative to the present mineral oils. This paper documents the research on naturally available mahua seed oil for bio-lubrication, its flash point and fire point, tribological properties namely coefficient of friction and wear scar diameter have been modified by the addition of zinc oxide (ZnO) nanoparticles in different concentrations by weight percentage (0.25, 0.50, 0.75, and 1.0). four-ball tester was used according to ASTMD-4172 standards (60 min under 40 kg running at 1200 rpm). Probe ultrasonicator was used for particle dispersion. It was found that 0.75 wt. % loading of ZnO in mahua oil resulted in a 57.14% drop of coefficient of friction, but a slight increase in the wear scar diameter of 30.60% was observed.

Increasing interest in utilizing bio-lubricants has been sparked by pollution caused by the mineral oil-based lubricants and their depletion. This study aimed to assess the effectiveness of Jatropha oil based grease as a basis and sodium thickener as an additive. The grease's lubricating abilities were tested using the ASTM 2266 four ball test and molybdenum disulphide as an additive. According to the findings, adding molybdenum disulphide particles decreased wear and the coefficient of friction, with the latter falling by 69% when compared to virgin Jatropha grease. Given that Jatropha grease passed the four ball test, a simulation of real-world conditions, this indicates that it is a reliable lubricant. Wear examinations were performed on steel balls using an optical microscope and scanning electron microscopy, and the results were consistent. It was found that addition of 0.25% MoS2 to virgin Jatropha grease reduced coefficient of friction to 0.12 (69%) from 0.39. Similarly wear scar diameter reduced from 800.583 µ to 788.44 µ in presence of 0.25% MoS2 blended grease. The study concludes that the grease prepared could an alternative to grease made from mineral oils. The focus on adopting Jatropha grease as a more sustainable and bio-degradable option can preserve the environment.

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

During co-action between contact elements in reciprocating motion, different working conditions exist in outer and inner zones of stationary elements. Because the tribological effects of surface texturing depend on the operating conditions, various dimple patterns were created in the middle part of the steel disc and near the reversal points. The behaviors of variable dimple patterns were compared with those of uniform texturing and untexturing. It was found that the dimple patterns in the middle disc zone depended on the resistance to motion. The best tribological behavior was obtained for a pit area ratio of 13% and diameter of 0.4 mm in the inner zone, and pit area ratio of 3% and diameter of 0.2 mm in the outer zones. Low resistance to motion and the smallest friction variation of all tested sliding pairs were achieved. For the same pit area ratio of 13% in a disc of 0.4 mm, the dimple diameter behaved better than in the 0.2 mm diameter disc. The greatest decrease in the coefficient of friction of 85% compared to untextured sliding pair was achieved for uniform laser texturing with a pit area ratio of 13% and dimple diameter of 0.4 mm, when the normal load was 40 N and frequency of displacement was 20 Hz. [ABSTRACT FROM AUTHOR]

The developments in manufacturing technologies are expected to reduce energy input without compromising product quality. Regarding the material densification process, numerical simulation methods are applied to achieve this goal. In this case, relevant material models are built using functions that describe the variation in mechanical parameters of the material in question due to its deformation. The literature review conducted for this research has revealed a shortage of experimental research methods allowing a determination of the coefficient of friction at low temperatures, approximately 200 K. This article proposes a method for determining the friction coefficient of dry ice sliding against steel. The experimental results were analysed to obtain several functions describing the variation in the coefficient of friction. These functions were then compared using goodness-of-fit indexes. Finally, two functions with similar goodness-of-fit values were chosen. The findings of this research project will complement the already available information and may be used in various research and implementation projects related to the development or improvement of currently used crystallised carbon dioxide conversion processes. [ABSTRACT FROM AUTHOR]

The object of the study is the process of changing tribological efficiency according to tribotechnical characteristics (wear intensity, friction coefficient, temperature in the contact zone) of composites based on phenylone C-1 and polyamide PA-6 with arimide-T filler and fullerene C-60. The study solved the problem of obtaining composites with high wear resistance. Based on the results of research, it was found that varying the content of arimide-T makes it possible to obtain composites with different patterns of changes in tribotechnical characteristics under conditions of dry friction, lubrication with water and I-50 oil. Composites with the composition: phenylone C-1+15 wt. have the maximum tribological efficiency. % arimide-T+3 wt. % fullerene C-60 and polyamide PA-6+30 wt. % arimide-T+3 wt. % fullerene C-60. Phenylone C-1 has destructive properties when working in the environment of water and temperature in the friction zone. Its reinforcement with arimide-T and fullerene C60 gave positive results of a complex of tribotechnical characteristics under these conditions. It was found that the wear of composites based on phenylone C-1 in I-50 oil is two orders of magnitude lower than in water. Research of samples from the obtained composites based on phenylone C-1 and polyamide PA-6, reinforced with the optimal content of arimide-T and fullerene C60, showed that their wear resistance when lubricated with oil is 3.5...4.0 times greater than the wear resistance of bronze. An applied aspect of the reported results is the introduction of manufacturing technologies and restoration of machine parts from the proposed composites. It has been proven that their optimal composition contributes to high tribological efficiency and could provide the required level of wear resistance and reliability of resource-determining nodes, systems, and machine assemblies. The results could be used by machine-building and repair-technological enterprises [ABSTRACT FROM AUTHOR]

Polyimide (PI) is a special engineering plastic, widely involved in mechanical components, instruments, and petrochemicals. However, single PI material is inevitably subject to wear and tear in practice, which leads to weakened material properties. In this work, Ti3C2Tx@SiO2 was prepared to enhance the wear resistance and lubrication properties of PI by intercalating SiO2 into the interlayer of Ti3C2Tx sheets. Ti3C2Tx@SiO2/PI composites were fabricated in two steps to test the tribological performances. SiO2 particles change the form of interfacial friction from sliding to rolling, thus relieving direct friction between material and steel ball. So, the composites have a minimum COF (COF = 0.33) when the content of Ti3C2Tx@SiO2 is 0.80 wt%. Moreover, the average value of wear rate was 0.24 × 10−5 mm3/(N·m) when Ti3C2Tx@SiO2 content was 1.60 wt%, which was 91.0% lower compared to the PI matrix. During the friction process, the abrasive chips of the material migrate to the surface of the steel ball to form a transfer film, which protects the material and thus reduces the wear rate. Therefore, the hybrids Ti3C2Tx@SiO2 are effective and important wear‐resistant agents and solid lubricants to improve the wear resistance and lubricity of PI or other polymer materials. Highlights: SiO2 insert Ti3C2Tx is a key factor in changing sliding friction into rolling friction, effectively reducing the COF.The average wear rate was 91.0% lower than that of the polyimide matrix when Ti3C2Tx@SiO2 content was 1.60 wt%.The minimum COF of Ti3C2Tx@SiO2/PI composites reached 0.33 when the content of Ti3C2Tx@SiO2 was 0.80 wt%.The transfer film effectively reduces further wear of the material during friction. [ABSTRACT FROM AUTHOR]

This article examines the correlation between the coefficient of friction and braking distance/time. Through comprehensive experiments and data collection, it was observed that as the coefficient of friction between a vehicle's tires and the road surface increased, the distance and time required for braking decreased proportionately. Factors such as tire state, road conditions, and vehicle weight, and braking system efficiency were considered. This correlation emphasizes the pivotal role of friction in vehicular safety, warranting further research and technological advancements in this domain. [ABSTRACT FROM AUTHOR]

The study investigates the deep drawing process for bimetallic sheets formed by bonding dissimilar metals (AA1100 aluminium alloy and C36000 brass) with epoxy-based adhesive. Experimental exploration of process parameters, including blank diameter, stacking sequence, lubrication, and strain rate, was conducted to analyse their impact on load–displacement behaviour and thickness strain distribution. Additionally, the study assessed fracture susceptibility, material flow characteristics (tearing and wrinkling), and the requisite drawing force for the bonded specimens. Results indicate enhanced formability and mechanical properties in bonded sheets compared to individual metal sheets, demonstrating the potential advantages of this approach. The bonded sheets demonstrated improved formability and mechanical properties compared to individual metals. Notably, the maximum drawing force for the bonded sheet (170 mm diameter) significantly increased to 24.2 kN, surpassing individual sheets by 69.85% for AA1100 and 40.54% for C36000. The analysis identified a vulnerable region (12–15 mm from the centre) under maximum risk of failure and consistent deformation patterns in samples with varying diameters and lubrication, providing valuable insights into the behaviour of bonded bimetallic sheets in deep drawing. [ABSTRACT FROM AUTHOR]