Anti-wear Properties Research Articles

Study on the wear performance of 304 stainless steel aerospace joint bearings

In order to investigate the influence of surface micro-texture on the oil film carrying capacity, a theoretical model of dynamic pressure lubrication is constructed based on CFD, and dynamic pressure lubrication simulation and friction and wear experimental research are used to analyse the influence of speed and load on the friction behaviour of the bearing pair, and the wear performance of the specimen is evaluated by means of the surface morphology and friction coefficient. The results show that the carrying capacity of the oil film on the textured surface is relatively large compared with that of the non-textured surface, showing regular fluctuations, and that the pressure values of turbulent flow are greater than those of laminar flow. As the rotational speed increases, the cavitation effect becomes more and more obvious, and the carrying capacity of the oil film increases. The smaller the thickness of the surface oil film, the higher the load carrying capacity and the lower the degree of wear; The surfaces of the textured specimens showed the best friction reduction and anti-wear properties, followed by the smooth surfaces and the worst rough surfaces. With the increase of rotational speed, the friction coefficient tends to decrease. When the rotational speed is 0.4 m s−1, the wear of the textured surface is reduced. With the increase of load, the thickness of the formed oil film decreases, the friction coefficient decreases, and the anti-friction effect of the textured surface increases. This indicates that the surface texure treatment of 304 stainless steel, and the selection of appropriate working condition parameters can effectively reduce wear during the friction process, and improve the wear resistance of bearings.

Investigating the Effects of Boron Nitride on Mechanical Properties of CoCrFeNiMn Composites

High‐entropy alloys (HEAs) are gaining attention for their exceptional properties but achieving precision and surface quality in powder metallurgy (PM) can be challenging. This study investigates the mechanical properties of CoCrFeNiMn HEAs produced through the flake powder metallurgy (FPM) technique and laser powder bed fusion (LPBF) preservative industrial, which established outstanding antiwear properties. To assess the enhancement of mechanical behavior and wear resistance by incorporating boron nitride (BN) into CoCrFeNiMn composites is fabricated via FPM. By incorporating BN into the composites, the mechanical behavior is significantly enhanced, leading to improved resistance against wear. Furthermore, the study delivers comprehensions into the serration behavior microstructure and shear localization in a high‐strain‐rate‐deformed CoCrFeMnNi entropy‐high alloy produces through metallurgy in powder. The serration behavior of the CoCrFeMnNi HEA is discussed concerning strain rate and temperature. Accordingly, the study employs the LPBF technique to fabricate the CoCrFeMnNi alloy from the prepared flakes. Microstructural characterization using scanning electron microscopy and X‐ray diffraction techniques to explore phase distribution, grain size, and possible segregation in the CoCrFeMnNi alloy produced through FPM‐LPBF is performed. In this particular investigation, a gradient microstructure is achieved through fusion in a laser‐powder bed of CoCrFeMnNi HEA onto highly deformed equal‐atomic HEA sheets. The resulting combination of partially recrystallized regions, exhibiting elevated yield strength, and fully recrystallized regions, demonstrates enhanced strain hardenability and elongation, and yields superior mechanical properties. The results obtained from the FPM‐LPBF CoCrFeMnNi alloy will be compared with those of conventionally processed CoCrFeMnNi to highlight the advantages and improvements achieved through the proposed method. The study findings reveal that the fundamental understanding of HEAs’ behavior under LPBF with FPM affords valuable insights into optimizing the processing parameters and achieving superior mechanical attributes.

Evaluation of the tribological performance and oxidative stability of a bi-functional lubricating oil additive prepared from corn cob extract

To meet the requirements of a circular economy, a class of sulfur- and phosphorus-free green bifunctional lubricating oil additives was developed based on corn cob extract as a naturally renewable biomass material. These additives can significantly enhance the friction-reducing, anti-wear properties, and oxidative stability of base oils. Results indicate that at an addition level of 4000 ppm, ternary polymer additive reduced the wear volume and surface roughness of steel friction pairs by 98.17 % and 97.63 %, respectively, and increased the oxidation induction period by 40.52 %. The improvement in tribological performance is attributed to the rigid ring structure preventing direct contact between friction pairs, and the chemical adsorption of carboxylic acid and anhydride groups with the metal, forming a dense friction film.

Synergistic Tribological Effects of Ti3C2Tx MXene and ZDDP under Simple Grafting Strategies for Efficient Lubrication.

MXenes, a novel class of two-dimensional materials, possess exceptional physical and chemical properties, positioning them as promising candidates for lubricant additives. However, their potential is constrained by challenges in dispersion and stability, coupled with a paucity of research on interactions with additives in full-formula oils. In this study, hexadecylphosphonic acid (HDPA) is grafted onto Ti3C2Tx to formulate a polyalkylene glycol dispersion system. The findings reveal that the HDPA-modified Ti3C2Tx (HDPA-Ti3C2) is successfully synthesized, demonstrating superior dispersion stability and notable friction-reduction and antiwear properties. Notably, when combined with zinc dialkyl dithiophosphate (ZDDP), the HDPA-Ti3C2/ZDDP composite additive outperforms single additives in tribological performance, suggesting synergistic effects between them. This enhanced performance may be attributed to the formation of an amorphous polyphosphate tribofilm offering wear resistance, followed by the generation of a TiO2 tribofilm that further safeguards and repairs the worn surface, thereby enhancing the load-bearing capacity. Concurrently, the interlayer sliding mechanism of nanosheets, which substitutes the relative motion of the friction pair, reduces friction under boundary lubrication, ensuring prolonged effective lubrication. This work broadens the application prospects of Ti3C2Tx MXene for the design and development of commercial lubricating additives.

Lubrication and antibacterial performance and mechanism of functionalized ionic liquids in glycerol media with different water contents

Glycerol lubricants face limitations in industrial applications due to their inadequate antimicrobial properties. In this study, a functionalized long-chain quaternary ammonium salt ionic liquid, BTA-16-BTA, was synthesized. The antimicrobial and tribological properties of BTA-16-BTA as a lubricant additive in glycerol media with different water contents were investigated. The results show that the antimicrobial performance of the glycerol medium is positively correlated with the amount of BTA-16-BTA added. At the optimal concentration of 1.5 % BTA-16-BTA dispersion, excellent friction-reducing, anti-wear, and extreme pressure properties were observed. The friction-reducing and anti-wear effects were further enhanced when 1 % water was added to the system. The liquid medium containing BTA-16-BTA can inhibit the growth of Escherichia coli, indicating that BTA-16-BTA possesses antimicrobial properties.

Exploring wear, corrosion, and microstructure in PEO coatings via laser surface treatments on aluminum substrates

The inadequate resistance to corrosion and wear of Al-based alloys is a major hindrance to their extensive use. Plasma electrolytic oxidation (PEO), a common and efficient coating technique, creates an oxide coating similar to ceramic on the surface of Al-based alloys, thereby improving their ability to withstand corrosion and wear. Studies have shown that PEO treatment can significantly enhance the short-term corrosion and wear resistance of Al-based alloys. To improve the long-term corrosion resistance of PEO coatings, researchers are now exploring the combination of laser processes with the PEO process. Laser processing is a simple yet efficient technique known for its flexibility, precision, and control. Various laser procedures are recognized for their ability to improve the resistance to wear and corrosion of PEO coatings applied on Al substrates and their alloys. Laser melting procedures have the capability to standardize and modify the microstructure of aluminum-based alloys. This review focuses on enhancing the anti-corrosion and anti-wear properties of aluminum alloys through the integration of laser surface treatments with PEO technology.

Synthesis and Performance Evaluation of Metallocene Polyalphaolefins (mPAO) Base Oil with Anti-Friction and Anti-Wear Properties

Anti-wear and anti-oxidation abilities are two key properties of lubricants that play a crucial role in ensuring long-term stable equipment operation. In this study, we aimed to develop a base oil with good anti-oxidation and anti-wear properties for use under extreme pressure. The as-prepared metallocene polyalphaolefin (mPAO) was chemically modified using the trifluoromethanesulfonic acid (TfOH) catalysis through an alkylating reaction with triphenyl phosphorothioate (TPPT). During the experiments, when the reaction temperature exceeded 70 °C or the concentration of TfOH exceeded 2.67%, the β-scission reaction in the alkylation process became significantly more pronounced. The physical and chemical properties of TPPT-modified mPAO (T-mPAO) were evaluated by nuclear magnetic resonance spectroscopy, Fourier trans-form infrared spectroscopy, gel–permeation chromatography, and ASTM standards. T-mPAO showed significantly improved antioxidant capacity, with the initial oxidation temperature increasing by 32 °C compared to the base oil, and it exhibited the slowest increase in acid number in the 96-h oven oxidation test. The tribological tests showed that T-mPAO had the lowest friction coefficient, wear track, and wear rate (72.7% lower than that of mPAO) as well as the highest PB (238 kg) and PD (250 kg) among all tested samples. Compared to mPAO, the average friction coefficient of TPPT-modified mPAO in the four-ball friction test was reduced by 30.5%, and by 16.4% in the TE77 reciprocating friction test. Based on the experimental results, T-mPAO had strong anti-oxidation ability and excellent lubricating performance.The successful synthesis of multifunctional mPAO has enabled lubricant base oil additization, making it possible to use it in more demanding work scenarios, greatly broadening its application scope and making lubricant formulation blending more flexible.

Tribological properties of a smart Ti3C2Tx-based epoxy coating: Providing an idea to solve the weak tribological properties of traditional smart coatings

Friction damage is always a major threat to the wide application of smart anticorrosion coatings. Here, the tribological properties of a smart Ti3C2Tx-based epoxy coating (MLT@EP) is adjusted by the reasonable collocation of mesoporous silica nanocapsules loading onto Ti3C2Tx-based plane (MLT). MLT@EP not only maintains good smart anticorrosion, but also has remarkable anti-friction and anti-wear properties. Its friction coefficient exhibits a low and steady trend, and the wear rate arrived at 1.14 × 10−5 mm3/N·m, which is decreased by 58.3 ∼ 93.3 % compared to control groups. The excellent tribological properties are mainly attributed to the synergistic effect of MXene-based lubrication film, high resistance to plastic deformation, and strong internal interaction.

Tribological performance of used engine oil treated with cement and celite adsorbents by solvent extraction-adsorption method

Purpose As lubricating oils are used, their performance deteriorates and they become contaminated. The purpose of this paper is to investigate the lubrication performance of reclaimed 5 W-30 a fully synthetic used engine oil (UEO) with wear tests after refining it from a solvent-based extraction method using solvent (1-PrOH) and adsorbent materials such as cement, celite and deep eutectic solvent (DES). Design/methodology/approach The treated oil mixtures were prepared by blending engine oils with various adsorbent materials at 5% (w/w) in organic 1-PrOH solvent at a UEO: solvent ratio of 1:2 (w/w). The measurement of kinematic viscosity, density, the total acid number (TAN) and elemental analysis of oil samples was done by the ASTM standards D445/D446, D4052, D974 and D6595, respectively. Adsorbents and treated oil samples characterized by SEM-EDX, FTIR and UV analysis, respectively. Meanwhile, lubricating performance in tribological applications was evaluated through the wear test device using a rotating steel alloy 1.2379 cylinder and a stationary 1.2738 pin under 20, 40 and 80 kg load conditions. Worn surface analysis was done with SEM and 2.5D images. Findings It was found that when using the combination of cement and celite as an adsorbent in the reclamation of used engine oil demonstrated better lubricant properties. The properties of used engine oil were improved in the manner of kinematic viscosity of 32.55 from 68.49 mm2/s, VI (Viscosity index) value of 154 from 130, TAN of 3.18 from 4.35 (mgKOH/g) and Fe content of 11 from 32 mg/L. The anti-wear properties of used engine oil improved by at least 32% when 5% cement and 5% celite adsorbent materials were used together. Research limitations/implications The paper is based on findings from a fully synthetic 5 W-30 A5 multi-grade engine lubrication oil collected after driving approximately 12.000 km. Practical implications The results are significant, as they suggest practical regeneration of used engine oil is achievable. Additionally, blending fresh oil with reclaimed used engine oil in a 1:1 ratio reduced wear loss by over 10% compared to fresh oil. Social implications Reusing used engine oils can reduce their environmental impact and bring economic benefits. Originality/value This study showed that the properties of UEO can be enhanced using the solvent extraction-adsorption method. Furthermore, the study provided valuable insights into the metal concentrations in engine oil samples and their impact on lubrication performance. The order of the number of the grooves quantity and the possibility of the observed scuffing region trend relative to the samples was UEO > 5W-30 fresh oil > Treated oil sample with the adsorbent cement and celite together. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-06-2024-0209/

Ionic liquid-functionalized ZnO nanomaterial: Multifunctional additives enhancing tribological performance and corrosion resistance in ester oil

A multifunctional nanomaterial (ZnO-IL), comprising zinc oxide modified with corrosion-resistant ionic liquid groups, was designed and synthesized. It was used as an additive in bis(2-ethylhexyl) sebacate (DIOS) to evaluate its tribological and corrosion resistance properties, and compared with the commercial additive sulfurized isobutylene (SIB). ZnO-IL exhibited good solubility and thermal stability in DIOS. Lubricants containing ZnO-IL showed excellent anti-wear performance under various loads and temperatures. Its deposition on metal surfaces and the synergistic action of benzotriazole groups in the anions effectively prevented corrosion on the surfaces of metal friction pairs, thereby addressing the challenge of friction pair corrosion caused by the hydrolysis of ester-based oils. The ZnO-IL nanomaterial rapidly formed an organic-inorganic multilayer adsorption film on metal surfaces through electrostatic interactions. During friction, a boundary lubrication film composed of ZnO deposition and friction chemical reaction films was formed, thereby avoiding direct metal contact, reducing contact pressure, and exhibiting outstanding friction reduction and anti-wear properties.

Performance assessment of graphene oxide based nano-cutting fluids during sustainable hard turning through synthesis, characterization and machinability investigation

Achieving sustainability in manufacturing necessitates the implementation of eco-friendly solutions by adopting environmentally friendly coolants with cost-effective, energy-efficient and cleaner production processes without posing any risk to the operator's health. In this current work, mineral oil-based graphene oxide (GO) nano-cutting fluids of different concentration (0.05, 0.1, 0.2, 0.3, 0.4, 0.5 % wt.) are synthesized and their characteristics such as rheological, thermo-physical and tribological properties along with their stability and toxicology impact are thoroughly investigated. Further, the influence of nano-cutting fluid concentration on machinability and sustainability aspects during hard turning such as flank wear, surface integrity, power consumption, cutting temperature, carbon and noise emissions are investigated. According to the result an enhancement of 28.83 % and 29.54 % in viscosity and thermal conductivity have been recorded when concentration of nanofluid increases from 0.05 % to 0.5 %. GO nano-cutting fluids shows anti wear and friction reduction properties by providing excellent lubricious properties, as a result coefficient of friction has been reduced up to 28.36 % at 0.5 % wt. GO compared to plane mineral oil. A notable reduction in flank wear, cutting temperature, surface roughness, cutting temperature, power consumption, carbon emission and noise emission were noticed to be 25.96 %, 27.82 %, 23.86 %, 25.22 %, 11.66 % and 2.72 % respectively when the concentration of GO nanoparticles increases from 0.05 % to 0.5 % wt. Smoother surface with minimal defect has been noticed from the SEM and AFM image of machined workpiece at highest concentration (0.5 % wt.) of GO due to the synergetic effect of GO nano-cutting fluid and dual nozzle MQL system.

Titanium surface functionalization via directed energy deposition of CuNiTi ternary alloy

Pure titanium is a soft material that tends to degrade quickly during service due to wear and microbiologically influenced corrosion. Therefore, current research aims at the deposition, microstructural characterization, and surface functionalization of the TiCuNi coatings on pure titanium substrate to improve its surface properties. Cu–Ni premixed elemental powders are deposited on the pure Ti by laser-directed energy deposition (LDED) using a novel method of extracting Ti from the substrate through melt pool convection. The single-track deposit geometry and integrity characterization using dilution percentage, heat-affected zone width (HAZ), and microhardness values show the sound metallurgical bonding with the substrate. The X-ray diffraction (XRD) pattern and microstructure image reveal the presence of NiTi binary (B2) and Ti2CuNi ternary (B19) hard phases and equiaxed dendritic morphology, respectively, demonstrating ternary alloy coating formation. The microhardness value of the coatings is thrice that of the substrate due to the presence of hard NiTi (B2) binary and Ti2CuNi (B19) ternary phases. The coating’s wear resistance is significantly (80%) higher than the substrate, owing to hard phases and Cu as a solid lubricant. The wear track consists of small grooves, adhered debris, and a smooth profile, mainly due to a significant reduction in adhesion and abrasion compared to the substrate. Moreover, the polarisation corrosion potential and current density are increased and decreased by 53% and 97%, respectively, displaying symbolic improvement in the corrosion resistance. Hence, this work has presented the LDED ability to enhance the pure Ti anti-wear and corrosion resistance properties by depositing CuNiTi ternary alloy coating for potential aerospace, marine, and biomedical applications.

Numerical Simulation on Lubrication and Experiment Study on Tribology Improvement of Slipper Pair at Low speeds

A mixed lubrication model for the slipper pair of an electric piston pump is proposed to solve problems such as inadequate lubrication, extreme friction, and wear at near-zero and low speeds. The lubrication characteristics of the slipper pair were numerically calculated and simulated, and the frictional characteristics in the low-speed range were analyzed. A self-lubricating and anti-wear slipper pair was developed to mitigate severe friction and wear at near-zero and low speeds. To improve the tribological properties of slippers, various concentrations of molybdenum disulfide (MoS2) powder mixed with epoxy resin (EP) were used as self-lubricating materials. The content of MoS2 ranged from 1 and 20 wt%. The optimal content of MoS2 was obtained by conducting frictional tests on the slipper pair samples as well as material examination and analysis of the slipper sample surfaces before and after the surface characterization tests. The lubrication mechanisms of the self-lubricating and antiwear slippers were determined. The EP/MoS2 composite lubricating materials exhibited excellent self-lubricating and anti-wear properties, providing a new direction for the optimized design of slipper pairs and other important friction pairs in piston pumps and promising research prospects.

Tribological properties of the P and S-free protic ionic liquids as water-based lubricants

Three kinds of P and S-free 1,8-Diazabicyclo[5.4.0] undec-7-ene water-soluble protic ionic liquids (PILs) were successfully synthesized and applied as additives in water-1,2-Propylene glycol (PG). The physicochemical properties of PILs and the anti-friction, anti-wear and anti-corrosion properties were investigated. Research results demonstrated that the addition PILs lubricant additive could greatly improve the tribological properties of water-1,2-PG. The addition of 5 wt% PILs with long alkyl chain will result in the reduction of friction coefficient and wear volume by about 45 % and 95 %, respectively. Meanwhile, the PILs with long-chain show more effect lubrication behavior than the short one. In addition, the obtained PILs also possess excellent anti-corrosion properties as water-based lubrication additives. The elemental analysis of the contact area showed that the PILs would generate a chemical reaction film during the friction process, and the carboxylate anion could form a chemical and physical adsorption film on the surface of contact area, which would provide better anti-friction and anti-wear properties.

Carbon dots grafted by oil-soluble polymer brushes derived from bis-alkyl chain monomers as a lubricant additive of poly-α-olefin with outstanding friction-reducing, anti-wear and anti-rust properties

The application of carbon dots (CDs) as lubricant additives of nonpolar oils such as poly-α-olefins (PAOs) has been greatly hindered because most of CDs derived from the bottom-up method were water-soluble. In this work, the oil-soluble polymer brushes grafted CDs were synthesized by the surface-initiated atom transfer radical polymerization of bis-alkyl chain monomers. As expected, the polymer grafted CDs exhibited the excellent long-term dispersion stability in PAO owing to the principle of similar compatibility. As the lubricant additives of PAO4, the CDs showed the best friction-reducing and anti-wear properties when the polymerization time was 2 h. Adding 1 wt% of CDs could make the coefficient of friction and wear volume of PAO4 reduce by 64.1 % and 49.6 %, respectively. Moreover, both the tribological properties and anti-rust performance of CDs were superior to the commercially used ZDDP. The distinguished friction-reducing and anti-wear properties of CDs were attributed to the synergistic lubrication of carbon cores and polymer brushes. The rolling, repairing and polishing action of carbon cores, together with the tribo-reactions of polymer brushes, resulted in the formation of tough lubricating films on the rubbing surfaces, thereby tremendously alleviating the friction and wear of tribopair. The impressive anti-rust performance of CDs could be assigned to their strong adsorption ability on metallic surfaces. The above results are hopeful to provide useful information for the design and development of efficient multifunctional additives such as polymer-grafted metallic or inorganic nanomaterials.

Influence of triangular texture composite MAO coating on the tribological properties of aluminum alloys

To compensate for the poor friction and wear performance of aluminum alloys, in this study, four triangular textures with different area occupancy rate (5.16 %, 9.17 %, 20.63 % and 28.07 %) were prepared on the surface of aluminum alloys by laser texture technology, subsequently micro-arc oxidation (MAO) coatings were prepared using MAO technique. The treated samples were characterised by X-ray diffraction, micro-morphological analysis, optical profiler and energy dispersive spectroscopy. The tribological performance under oil lubrication conditions was tested by using a pin-disc contact rotational friction wear tester. The results showed that the sharp corners at the edges of the texture caused current concentration, which resulted in more intense sparking and accelerated MAO growth, thus creating more pores and roughening the surface of the coating. In terms of tribological performance, the triangular texture with 9.17 % area occupancy rate showed the best tribological performance before MAO coating, compared with the substrate, the average friction coefficient decreased by 64.11 %; and after the MAO coating was applied, the triangular texture composite MAO coating with 9.17 % area occupancy rate still had the best tribological performance, and its average friction coefficient further decreased compared with that of the smooth MAO coating by 33.07 %. The analysis suggests that the texture can store abrasive particles to prevent the MAO coatings from being worn through, leading to coating failure, while the hard MAO coatings can resist contact stresses well enough to prevent the texture from being flattened, leading to the failure of the function of storing abrasive debris. Therefore, the integration between texture and MAO coating can greatly enhance the anti-wear properties of aluminum alloys.

Tribological mechanisms of the synergistic effect between phosphate based ionic liquids and metal-organic frameworks

Sulfur-free green lubricant additives have received more attention in industrial production. In this study, tri-octyldodecyl phosphonium diisooctyl phosphate （P/P）with UiO-66 composite environmentally friendly lubricating additives were synthesized. The tribological properties of P/P with UiO-66 composite additive in polyalphaolefin-6 (PAO-6) heavy were systematically conducted. The outcomes showed that 1 % P/P@3000 UiO-66 additive had excellent friction reduction and antiwear properties. This was mainly due to the adsorption of oil-soluble P/P on the surface and within the pores of UiO-66, which effectively reduced the tendency of agglomeration of UiO-66 formed a good synergistic effect. Consequently, a favorable and stable balling effect was achieved, thereby preserving the integrity of the lubricant film, resulting in significantly reducing wear from shear and abrasive.

Friction Mechanism of Sulfur-Containing Lubricant Additives Confined between Fe(100) Substrates.

Sulfur-containing lubricant additives can chemically react with metal surfaces under extreme conditions, such as high temperature and high pressure, forming protective films on the surfaces. However, the formation mechanisms and the friction-reducing and antiwear properties of these films remain unclear. In this study, we investigated the friction process of sulfur-containing additives confined between two iron surfaces using reactive molecular dynamics simulations. Our research revealed that in systems with a higher S/C ratio, an iron sulfide layer formed on the iron surfaces with Fe-S-Fe bridging bonds at the interface, resulting in relatively smaller friction and wear even under higher loads. However, in systems with lower S/C ratios, the presence of numerous interfacial Fe-Cn-Fe bridging bonds, caused by the hydrocarbon radicals released from the additives, led to the formation of thick amorphous shearing bands at the interface between the two substrates. In this case, the distributed sulfur atoms also exhibited some effect in reducing the shear resistance of the amorphous shearing bands due to the weak strength of S-Fe bonds compared to the strength of C-Fe bonds. These atomic-level insights help understand the antiwear characteristics of sulfur-containing lubricant additives confined between iron substrates.

Investigation of sliding wear, electrochemical corrosion, and biocompatibility of Ti-Nb alloys for biomedical applications

This research emphasizes the development of biocompatible Ti-xNb (0, 5, 10, 15, 20, and 25 wt.%) alloys through powder metallurgy to attain a lower elastic modulus, high strength, low wear, and high corrosion resistance appropriate for biomedical implants. The developed alloys were comprehensively analyzed through microstructural, physical, mechanical, electrochemical, biological, and tribological investigations to assess their suitability by comparing their properties with commercially pure titanium (cpTi). The outcomes demonstrate, powder metallurgy is an effective route for developing Ti-Nb alloys with several desirable properties. Incorporating niobium (Nb) into titanium (Ti) introduces the β phase within the alloys, which increases with Nb concentration and contributes to decreasing the elastic modulus to as low as 43.47 ± 4.9 GPa. All Ti-Nb alloys exhibits higher hardness and compressive strength than cpTi, with values of 403.23 ± 21.38 HV and 1322.45 ± 25.64 MPa obtained for the Ti-10Nb alloy. A lower concentration of Nb shows comparable corrosion resistance of the Ti-Nb alloys to cpTi, whereas a higher Nb concentration is unfavorable. Furthermore, the tribological findings demonstrate superior antifriction and antiwear properties in all Ti-Nb alloys compared to cpTi. Notably, Ti-10Nb displays outstanding wear resistance with a 41.82% lower friction coefficient in dry conditions and 31.11% in simulated body fluid (SBF), along with 81.08% reduction in wear volume in dry conditions and 63.11% in SBF compared to cpTi. Among all developed alloys, Ti-10Nb exhibits various desired properties, suggesting its potential as an alternative to cpTi for biomedical implant applications.

POWER SUPPLY UNIT OF THE STAND AND LABORATORY INSTALLATION FOR TREATING OLIVES WITH ELECTROSTATIC FIELD

Most technological machines (TM) use hydraulic drives and internal combustion engines, such as lifting and transporting, loading and unloading, construction, road, track, and mining. Increasing the durability of the specified TM units is an urgent task. One of the possible solutions to this urgent problem is the electrostatic treatment of hydraulic oils and diesel fuels. Over the past three decades, researchers have conducted many studies focused on finding optimal means of using external force fields to improve the quality of lubricating materials and intensify their production. Types of influence of force fields, such as mechanical, mechanochemical, acoustic, electromagnetic, and electric, are increasingly used to regulate the behaviour of dispersed particles in nonpolar and slightly polar environments. The theory of regulated interphase transitions proves that the emergence, growth, and size change of supramolecular structures, surrounded by an adsorption-solvate layer and creating complex structural units in oil dispersion systems, contribute to the emergence of new properties of these systems. One of the main provisions of this theory is the need for extreme and antibating changes in the size of complex structural units with the help of external influences, which include force fields. Lubricating materials differ in their degrees of dispersity, composition, and properties, so the effect of force fields on them is diverse. The ability to regulate intermolecular interactions and the size of complex structural units are significant in the operation of lubricants. Electric fields make it possible to control phase interactions in these dispersed systems: they increase the constant dipole moments of particles and the electrosurface forces, which contribute to the deformation of the electric double layer. Under the action of strong electric fields, structural changes occur in hydrocarbon dispersion systems, which significantly change the physicochemical properties of lubricating materials. Thus, the dynamic viscosity of the lubricant and its resistance to deformation may change depending on the chemical nature of the system. Previously conducted experimental studies allow us to formulate the requirements for the stand in detail, which enables investigation of the properties of petroleum-based liquids. Thus, it is possible to achieve increased anti-wear properties of petroleum-based liquids when the liquid passes through the gap between the electrodes in an electrostatic field. The voltage between the electrodes should be U = 1000–1500 V, and the speed of the liquid movement in the space between the electrodes should be V = 4.5–6.5 m/s. The power supply unit of the stand for electroprocessing petroleum-based liquids, proposed in this paper, meets these requirements. The article proposes a fundamentally new scheme for the power supply unit of the laboratory stand for direct current electrotreatment of petroleum-based liquids. The power supply unit is a bipolar source of adjustable direct current. It provides smooth regulation of the voltage from 0 to 3000 V and step regulation of the output current. The block has double protection against short circuits at the output and input. Keywords: anti-wear property, oil, influence of an electrostatic field on the anti-wear properties of oil, device for electrostatic treatment of oil.