Good Antifriction Properties Research Articles

Investigation of the elevated temperature tribological property and wear mechanism of Fe‐15Cu‐0.8C materials containing Mo‐coated MoS2 powders

In this work, MoS2 solid lubricant was introduced in the form of Mo‐coated MoS2 powder, to enhance the antifriction properties of sintered ferrous antifriction materials (FAMs). The microstructure, phase composition, and tribological properties of Fe‐15Cu‐0.8C‐3.75 (Mo‐coated MoS2) (MC1) were investigated and compared with Fe‐15Cu‐0.8C (M0) samples, with a discussion on the wear mechanism at a wide temperature range of room temperature (RT) to 600 °C. The study revealed that the addition of Mo‐coated MoS2 powders effectively prevents the decomposition of MoS2 during sintering, enhances the bonding strength between MoS2 and the substrate, and significantly improves the hardness of the sintered Fe‐15Cu‐0.8C samples. In comparison to the sintered Fe‐15Cu‐0.8C samples, the sintered Fe‐15Cu‐0.8C‐3.75(Mo‐coated MoS2) samples exhibit good antifriction properties with a frictional coefficient of 0.23 at 600 °C and a wear rate of 6.3 × 10‐7 mm3/N·mm at 300 °C. Introducing Mo‐coated MoS2 significantly reduces the average friction coefficient and wear rate of the sintered FAMs at elevated temperatures, attributed to the formation of FeMoO4. The antifriction performance of MC1 samples notably decreases with increasing test temperatures. The main wear mechanism is oxidative wear above 300°C.This article is protected by copyright. All rights reserved.

Tribological studies of materials for sliding bearings when lubricated with hydraulic fluid

Tribological research of materials BrOPh6.5-0.15, PH4M paired with 40X steel and lubricated with hydraulic fluid AMh-10 showed good antifriction properties. The results of the research on the influence of load, speed and temperature on the coefficient of friction of materials: BrOPh6.5-0.15 and PH4M when lubricated with AMh-10 hydraulic fluid. At a load of 0.5447 MPa, the coefficient of friction of BrOPh6.5-0.15 material at a temperature of 90°C is 1.58 times higher, and at a load of 2.003 MPa, the coefficient of friction of BrOPh6.5-0.15 material is 2.85 times higher than the coefficient of friction of BrOPh6.5-0.15 material at a temperature of 20°C. Materials BrOPh6.5-0.15 and PH4M are promising for application in plain bearings of pumps pumping hydraulic fluid AMh-10.

Dispersion stability and tribological behavior of nanocomposite supramolecular gel lubricants and molecular dynamic simulation

The poor dispersion stability of nanoparticles in oils limited their application. To address this problem, diverse of nanoparticles were introduced to supramolecular gels to fabricate a new lubricant (Nano-Gel). The results of molecular dynamics simulation show that gelators adsorbed onto the surface of nanoparticles at the non-covalent interaction. Besides, the intricate networks of supramolecular gels show spatial confinement to nanoparticles, which improved the dispersion stability of nanoparticles. Compared with supramolecular gels lubricant, Nano-Gel shows good anti-friction and anti-wear properties. The excellent tribological properties would be contributed to the self-repairing and tribo-film formed by nanoparticles and gelators. The Nano-Gels provide effective solution to the application of nanoparticles in lubricating oil, which have great values to prolong the life of mechanisms.

Double cross-linked transparent superhydrophilic coating capable of anti-fogging even after abrasion and boiling.

The commercial application of surfaces with superhydrophilic (SHPL) properties is well known as an efficient strategy to address problems such as anti-fogging, anti-frosting, and anti-biological contamination. However, current SHPL coatings are limited by their poor water and abrasion resistances. Thus, herein, to solve these problems active glass was employed as a substrate, and a stable and transparent SHPL solution was prepared via the spraying process. Aqueous polyacrylic resin (PAA), SiO2 nanoparticles (NPs), tetraethyl orthosilicate (TEOS), and sodium allyl sulfonate (SDS) were utilized as the four main components of the PAA-TEOS-SiO2 coating. The durability properties including anti-abrasion, resistance to water, and contact component loss were investigated via the Taber abrasion test, boiling water immersion test, and anti-fogging test, respectively. Furthermore, the structure, composition, and wettability of the coating before and after the friction and water immersion tests were compared via water contact angle (WCA) measurements. Furthermore, the effect of the type of resin on the properties of the coating was investigated. The surface morphology of the blended water-based polyacrylic acid (PAA) resin was uniform and flat and its adhesion to the substrate was the highest (4.21 MPa). Considering the durability and optical properties of the coating, the optimal blend was 3 wt% PAA resin, which exhibited a transmittance of 90%. When the content of TEOS, which enhanced the crosslinking in the coating, was increased to 2 wt%, the results showed that the SHPL coating maintained good anti-friction, boiling resistance, and anti-fogging properties under the conditions of 300 cycle Taber friction with 250 g load and soaking in hot water at 100 °C for 1 h. In particular, the excellent durability of strong acid and alkali resistance, heat resistance, and long-term aging resistance will facilitate the commercial viability and expand the application of SHPL coating in various research fields.

Stable low‐friction carbon/epoxy composites using carbon nanocages stuffed with ionic liquids as fillers

AbstractEpoxy resin (EP) is prone to brittle fracture during friction due to internal stress after curing, resulting in fatigue wear and cracking. Adding carbon fillers is considered as one of the great potential solutions to solve the serious dry wear of EP. Herein, we develop a novel carbon capsule composite filler (CNC‐IL) filled with ionic liquid (IL) in carbon nanocages (CNC) using the vacuum principle to address these concerns. Compared with pure EP, the friction coefficient (0.10) and wear rate (1.712 × 10−6 mm3 Nm−1) of the optimized CNC‐IL/EP were reduced by 74.62% and 88.14%, respectively. Such excellent tribological properties can be attributed to the solid–liquid lubricating film formed by the IL released from the broken CNC during friction. A low‐shear‐resistance slip layer can be formed between the CNC‐IL in the film due to the repulsion of the isoelectric ions adsorbed on the surface of the CNC; it effectively integrates the self‐lubricating functions of CNC and the liquid lubrication functions of ILs. This work provides a valuable idea for designing C/EP composites with good antifriction properties.

Tribological properties of Ni3Al-Ti3SiC2-MoS2 composite films deposited on textured surfaces by electrohydrodynamic atomization

This study aims to provide a convenient process for improving the tribological properties of Ni3Al matrix composite films. A sharkskin-inspired microtexture was developed using laser surface texturing technology on a GH3044 superalloy. Electrohydrodynamic atomization technology was subsequently utilized to deposit Ni3Al matrix composite films on the substrate surfaces. The corresponding synergistic tribological behavior of Ni3Al matrix composite films and laser surface texturing was evaluated through friction tests. Results indicated that the Ni3Al matrix composite films containing 8% Ti3SiC2 and with a sharkskin-inspired microtexture exhibited good anti-friction properties and wear resistance.

Synthesis of hydroxyl ether based biolubricant from poultry waste and to evaluate the friction performance with titania nanoparticles

Low-cost chicken waste fat, with a high content of palmitic acid (saturated fatty acid) and oleic acid (unsaturated fatty acid) was used for biolubricant production. The effects of different reaction parameters on the fat transesterification reaction using potassium hydroxide to form fatty acid methyl esters were investigated. In this study, the methyl esters from chicken waste fat were chemically modified to produce hydroxyl ethers (biolubricants) through epoxidation, followed by the ring-opening reaction of the epoxides with isoamyl alcohol in the molar ratio of 3:1 (alcohol:methyl esters) using the acid catalyst p-toluene sulfonic acid. The biolubricant obtained after the ring-opening of the methyl epoxides exhibited higher oxidative stability (OS) (18 h) than that of the biodiesel (3.85 h). The viscosity index of the biolubricant was found to be 295.32. The tribological performance of the biolubricant was enhanced by the addition of TiO2 (0.05% w/v). The biolubricant with 0.05% TiO2 led to a 25% reduction in friction coefficient and also enhanced the viscosity by 1.1-fold. Thus, TiO2 is suggested as a good antifriction property enhancer and viscosity modifier for the chicken waste lubricant. In summary, the chicken waste fat can be considered a feasible alternative to formulate biolubricants that match the physicochemical and low-temperature properties of commercial hydraulic oils.

Assessment and Optimization of Tribological Parameters for Bionic Textured AISI 4140-SnAgCu Self-Lubricating Composite Under Dry Sliding Conditions Using AHP and RSM

Herein, the analytic hierarchy process (AHP) and central composite experimental design in response surface methodology (CCD-RSM) are used to evaluate and optimize the tribological parameters of bionic textured AISI 4140-SnAgCu self-lubricating composite under the conditions of load (L: 20–40 N), velocity (V: 16–32 mm/s), and distance (D: 40–80 m). AISI 4140 biomimetic composites exhibit excellent tribological properties under the conditions of L 27.15/V 16.43/D 40, L 27.05/V 17.08/D 60, and L 27.42/V 17.85/D 80, respectively. The sensitivities of influence factors on the tribological overall score are load, velocity, and distance, in order from high to low. The good antifriction properties of self-lubricating composites under conditions with the optimized tribological parameters benefit from the fact that the solid lubricants are uniformly spread at the contact interface.

Improving the antifriction properties of the housing-rotor coupling in axial turbomachines

The article discusses the frictional interaction of carbon-carbon composite material on steel. Antifriction properties and wear resistance of the material under dry friction at speeds up to 100 m/s are investigated. The effect of velocity and contact pressure on the friction coefficient and wear resistance of a carbon composite is analyzed. The regularities of the change in the coefficient of friction are determined depending on the load-speed factors. The assumption is substantiated that the high thermal stability of the carbon composite, its low hardness, good antifriction properties and high wear resistance allow the material to be used in friction units operating at very high speeds and temperatures. In order to improve the reliability and reduce gas flows in axial turbomachines, on the basis of the study carried out, it is recommended that instead of heat-resistant coatings, a lining of the gas duct casing should be made of carbon composite.

Tribological properties of biocompatible molybdenum selenide nanoparticles as water lubrication additives for ultra-high molecular weight polyethylene/304 stainless steel contact

A hydrothermal method was adopted to synthesize molybdenum selenide (MoSe2) nanoparticles, which exhibited excellent dispersibility and biocompatibility in water. The morphology and structures of the MoSe2 nanoparticles were analyzed using scanning electron microscopy and transmission electron microscopy and were found to be flower-like. Furthermore, ball-on-disk tribological experiments were conducted using a UMT-2 tribometer to evaluate the lubrication effects of MoSe2 nanoparticles as an additive for water. The results indicated that the addition of MoSe2 nanoparticles in water could decrease the friction coefficient by 55.4 %, and the wear rate also decreased by 65.8 %. The good anti-friction and anti-wear properties of MoSe2 nanoparticles were ascribed to the layered structure that easily slipped and the filling and patching effect on the disk surface caused by these nanoparticles. MoSe2 water lubricants are expected to be used in real-life applications.

Effect of Graphene Content on the Micromorphology, Microhardness and Micro Frictional Resistance of Co-Ni-Graphene Composite Coating

In order to obtain the alloy composite material with high hardness, good anti-friction property and low friction coefficient, the electrodeposition technology was used to prepare nanocrystalline Co-Ni-graphene composite coating on the surface of low carbon steel by means of ultrasonic dispersion combined with mechanical agitation. The influence of graphene content in electrolyte on composite coating was studied. The surface microstructure, composition, phase structure, micro-hardness and micro-wear properties of composite coating were measured by scanning electron microscopy, energy spectrometer, X-ray diffractometer, micro-hardness tester and UNMT-1 comprehensive mechanical testing system for micro-nanometer materials. The results show that with the increase of the content of graphene in the electrolyte the graphene particles were embedded in the alloy coating, which changes the crystal structure of the alloy coating and improves the microhardness and micro friction resistance of the coating. When the content of graphene in the electrolyte was 0.9g/L the microstructure of the composite coating was fine and uniform, the highest microhardness value was 678 HV, the minimum average friction coefficient was 0.15, and the composite coating had good wear resistance.

Design and Evaluation the Anti-Wear Property of Inorganic Fullerene Tungsten Disulfide as Additive in PAO6 Oil

Inorganic fullerene-like tungsten disulfide particles have been proved to have good anti-friction and anti-wear properties as lubricating materials. As far as we know, however, when it is used as a lubricant additive, its behavior and action mechanism in the friction process are rarely studied. Herein, IF–WS2 particles were synthesized by a Chemical Vapor Deposition (CVD) method. The effect of IF–WS2 particle concentrations in the PAO6 oil on the tribological behaviors was investigated with a four-ball wear machine at both 75 and 100 °C. Additionally, the analyzed morphology and composition of nanomaterials and worn surfaces were analyzed by Scanning electron microscopy (SEM), Transmission Electron Microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The friction behavior in actual working conditions was studied by a wear testing machine. The experimental results show that compared with the original PAO6 oil, at a dispersion of 0.25 wt% in PAO6 oil, the IF–WS2 particles showed the best performance in terms of coefficient of friction, wear scar diameter and wear mass, which significantly reduced by 27%, 43% and 87%, respectively. At the same time, in the process of friction, it was found that IF–WS2 particles accumulated in the depressions to fill the scratches, and adsorption films and chemical films, including FeS2, WS2 and WO3, were formed on the worn surfaces to avoid the direct contact among the friction pairs more effectively, resulting in the improved anti-wear performances. Additionally, the addition of IF–WS2 particles effectively delayed the rise of lubricating oil temperature. In addition, dispersant span 80 can effectively improve the dispersion and stability of IF–WS2 in PAO6. This work provides us for understanding the effective lubrication mechanism of IF–WS2 particles in more detail and having a new acknowledge of the comprehensive performance of IF–WS2/PAO6 oil.

Influence of Laser Power and Scanning Speed on the Formation of Single Tracks Formed by Laser Cladding

One of the well-known methods for increasing wear resistance, especially for friction pairs, is surfacing wear-resistant materials on the working surfaces of mating parts [1, 2, 3]. Less expensive grades of steel can be used as the main material in the manufacture of parts, and the surfacing materials in this case must have increased characteristics: mechanical, corrosion and radiation resistance, heat resistance, wear resistance; good anti-friction properties, i.e. more expensive [4, 5]. This significantly reduces the cost of manufacturing or repairing parts, especially in mass production, since cheap grades of steel are used for their manufacture [5, 6]. Improvement of parts by gas powder laser cladding is carried out in shipbuilding, energy, oil and gas and mining industries, in the aviation industry and others. Note that although the method of coating appeared a long time ago, various methods of applying surfaced coatings are still being developed and refined [5,6]. In gas powder laser cladding, coatings are obtained by forcing the powder flow directly into the laser radiation zone [7, 8]. The powder particles are heated in the laser radiation zone and fall on the treated surface (substrate). It is known that the powder particles melt only after they hit the substrate [3, 4], but at the same time the surface layer of the base metal melts. After heating and melting the substrate, a liquid melt bath is formed, which, along with the molten powder, contains a significant part of the base metal components [7, 8]. The intensity of saturation of the surfacing metal with the substrate components is characterized by the proportion of the base metal in the cross section of the track, which is determined by the mixing ratio [9, 10, 11]. It is equal to the ratio of the area of the melted substrate to the sum of the areas of the melted substrate and the track as a percentage and depends on the cladding modes, which is determined after metallographic studies of the structure of protective coatings [8].

Specific Features of Reactive Pulsed Laser Deposition of Solid Lubricating Nanocomposite Mo-S-C-H Thin-Film Coatings.

This work investigates the structure and chemical states of thin-film coatings obtained by pulsed laser codeposition of Mo and C in a reactive gas (H2S). The coatings were analysed for their prospective use as solid lubricating coatings for friction units operating in extreme conditions. Pulsed laser ablation of molybdenum and graphite targets was accompanied by the effective interaction of the deposited Mo and C layers with the reactive gas and the chemical states of Mo- and C-containing nanophases were interdependent. This had a negative effect on the tribological properties of Mo–S–C–H nanocomposite coatings obtained at H2S pressures of 9 and 18 Pa, which were optimal for obtaining MoS2 and MoS3 coatings, respectively. The best tribological properties were found for the Mo–S–C–H_5.5 coating formed at an H2S pressure of 5.5 Pa. At this pressure, the x = S/Mo ratio in the MoSx nanophase was slightly less than 2, and the a-C(S,H) nanophase contained ~8 at.% S and ~16 at.% H. The a-C(S,H) nanophase with this composition provided a low coefficient of friction (~0.03) at low ambient humidity and 22 °C. The nanophase composition in Mo–S–C–H_5.5 coating demonstrated fairly good antifriction properties and increased wear resistance even at −100 °C. For wet friction conditions, Mo–S–C–H nanocomposite coatings did not have significant advantages in reducing friction compared to the MoS2 and MoS3 coatings formed by reactive pulsed laser deposition.

РОЗРОБКА ТОНКОШАРОВИХ ПОКРИТТІВ НА ОСНОВІ ФЕНІЛОНУ ДЛЯ ЗАХИСТУ ПОВЕРХОНЬ ВІД ГАЗО- ТА ГІДРОАБРАЗИВНОГО ЗНОШУВАННЯ

Relevance of the research topic. The task of increasing the wear resistance of parts and friction units is due to the tendency to increase their productivity and, consequently, workloads, speeds, temperatures and other parameters. Formulation of the problem. To improve the performance of friction joints, it is necessary to use materials that combine good adhesive and antifriction properties. Analysis of recent research and publications. There are a significant number of publications on materials with high antifriction properties and separately with high adhesion properties. Selection of unexplored parts of the general problem. There is no information on materials that would combine high adhesive properties and good antifriction properties as surfaces that are under gas and hydroabrasive wear. Setting objectives. The aim of this research is to investigate the combination of adhesive and antifriction properties of phenylon-based materials. Presenting main material. The adhesion ability of phenylon to classical materials of machines parts and its wear resistance at gas and hydroabrasive wear are investigated. The dependence of intensity of wearing from the angle of attack of the abrasive material is given. Conclusions in accordance to the article. It was found that, independently of the mode of operation, the greatest wear of phenylon-based coatings occurred at angles of 45°-60°, and starting from the angle of attack of 45 ° changed the mechanism of wear from microcutting to knocking out the polymer in the middle of the test sample. In both modes of operation, phenylon-based coatings were quite stable, which indicates the possibility of using phenylone as a coating to protect against gas-abrasive wear. But further research is needed, which will be closer to the real operating conditions, with the search for fillers to increase the wear resistance and adhesion of the coating based on phenylon.

Tribological properties of nano/ultrafine-grained FeCoCrNiMnAlx high-entropy alloys over a wide range of temperatures

Previous studies have shown that high-entropy alloys (HEAs) have good wear resistance, especially at elevated temperatures. However, for nano/ultrafine-grained bulk HEAs, there is a lack of understanding of the friction and wear properties. In this work, nano/ultrafine-grained FeCoCrNiMnAlx HEAs were produced by powder metallurgy, and the effects of Al addition and temperature on the friction and wear properties of the alloys were studied. The addition of Al led to grain refinement, body-centered cubic (BCC) phase precipitation and an increased hardness, which significantly improved the wear resistance of the alloys at various temperatures. At elevated temperatures, such as 800 °C, the alloys (especially the Al-containing alloys) exhibited outstanding wear resistance, which was mainly attributed to the formation of the continuous and dense oxide film on the worn surface due to the nano-/ultrafine-grained structure. Additionally, the Al-containing alloys also showed good antifriction properties at 800 °C.

Use of Nanoparticles of a Finely Dispersed Silicon Carbide Obtained in an Electrothermal Boiling Bed as a Structural Modifier of Thermoplastic Polymers

Porous powders of a finely dispersed silicon carbide obtained as a result of the carbothermal reduction of silica in an electrothermal boiling-bed reactor were investigated. It was established that such a powder comprises silicon-carbide nanoparticles of size ~50–70 nm and filametry formations of these nanoparticles with an aspect ratio of ~5–15. It is shown that the silicon-carbide nanoparticles introduced in a thermoplastic polymer interact with its matrix and, in so doing, change the polymer structure, with the result that a composite material is formed. Such thermoplastic polymer composites possess enhanced physical, mechanical thermal, and thermophysical properties. New heat-conducting polymer composite materials having a high wear resistance and good antifriction properties have been developed. These materials can be used in machine building as protective coatings, members, and units of facilities operating in the regime of abrasive wear, in power and electrical engineering, and in microelectronics where there is a need for heat-conducting thermoplastic polymer materials.

Comparative Study on the Friction Property of Bearing Steel Modified Bygraphite/MoS2 Composite Coating and Manganese Phosphate Coating

Surface modification is an important method to improve the contact fatigue life of transmission parts. The preparation of high performance coating with good tribological properties on the gears and bearings has become the research trends. This paper presents graphite/MoS2 composite spray and manganese phosphate conversion coating prepared on the AISI52100 steel surface and investigates their anti-fatigue mechanism. The tribological properties of the modified layers were studied using a SRV-IV multifunctional friction and wear tester. The microstructure and interfacial components of the coating and wear surfaces were analyzed by SEM and EDS, respectively. The surface morphology and phase composition of the coating were evaluated through laser 3D microscopy and XRD analyses, respectively. Both modified layers showed good anti-friction and anti-wear properties. The friction coefficients of the surfaces modified by manganese phosphate coating and graphite/MoS2 decreased by 7 % and 14 %, respectively, and the corresponding extreme pressure properties increased by 11 % and 55 %, respectively. But the mechanism of anti-fatigue wear and the corresponding interfacial phenomena of the surface modification of the graphite/MoS2 composite spraying layer is different from those of manganese phosphate coating. The hard-ceramic particles with graphite and MoS2 are sprayed on the substrate to obtain the surface hardening layer, resulting in higher wear resistance. The graphite and MoS2 modified layer can greatly reduce the friction coefficient and improve the lubrication performance on the surface. Manganese phosphate coating serves as a chemical soft coating and is filled with rough corrugated caused by surface processing, which induces an ideal meshing surface after initial friction phase. The obtained hole-shaped structure and "infiltration" role contribute to the storage of lubricants and thus improves the lubrication performance.

Ionic Liquids and its Potential in Lubricants: A Review

Lubricants have been associated with advancement of the human civilization with the changing priorities from “Transportability” in prehistoric times to “Longevity” in the modern times and then lately to “environment friendly”. Ionic liquids (ILs) are the room temperature molten salt and compounds of cations and anions. There are thousands of cations and anions hence millions of unique ILs are possible. The discovery of ILs have opened new frontier of research in many disciplines of science, one of the promising field is energy efficient and eco-friendly lubricants. First article on ILs as neat lubricant was published in year 2001 and till year 2011 ILs were being studied as base (neat) oil. The first oil soluble IL was synthesised in year 2012 and showed good anti-wear and anti-friction properties. This work gives the brief introduction of ILs and some of the recent advancements in developing ILs as additives for lubrication with an attempt to correlate oil-solubility, and lubricating behaviour. ILs are recent additives and still not commercialised in lubricants and its synergy need to be studied along with the other additives. This work will also focus on Influence of IL’s concentration in lubricants and the synergy between ILs and other additives in the synthesis of lubricants. At the end direction for future research has been discussed.

Synthesis and friction properties of a multifunctional diamond-containing ceramic material

Abstract The paper investigates the fundamentals of the technology of forming multifunctional composite diamond-containing materials with a ceramic matrix of an aluminum oxide. It shows the results of comparative tests of triboengineering properties of the obtained material. The developed technology for creating a billet for a diamond-containing composite ceramic material uses powder metallurgy (aluminum powder and dispersed diamonds). The paper determines optimal modes to form a billet. A sample of a composite mixture has been modified by microarc oxidation. It had a hardened layer of a ceramic matrix on its surface, and a dispersed diamond evenly enclosed in it. There is a description of features of the microarc oxidation technological process of a part from a sintered diamond-aluminum mixture compared with aluminum alloys. It is determined that the thickness of the formed ceramic layer is several times higher compared with the parts made of non-porous aluminum alloys. Moreover, the alkali concentration in the electrolyte and the relative density of a sintered billet have the greatest effect. There are two types of ceramic diamond-containing materials based on the proposed technology. They are: antifriction construction materials for sliding friction units and tool materials for abrasive processing. Triboengineering tests of materials with a small grain size of diamonds revealed their good antifriction properties even without lubricating with liquid materials. It has been established that an abrasive tool made from a material with a high grain size of diamonds has higher wear resistance and productivity compared with traditional abrasive materials.