Improvement Of Tribological Properties Research Articles

A novel strategy to significantly improve wear resistance of amorphous alloys by immersion in NaOH solution

The application of amorphous alloys in tribology is constrained by their inherent brittleness. An alkaline treatment (AT) can address this limitation by hydrogen generated rejuvenation. Following AT in a 3 mol/L NaOH solution for 3 days, the hardness of as-cast Ti-based amorphous alloys decreased by about 10 %, while the relaxation enthalpy increased approximately 2.2 times. Concurrently, the average coefficient of friction (COF) decreased by more than 15 % under all test loads except at 10 N. Additionally, the wear rate significantly decreased by over 20 %, with a notable reduction of about 25 % under a 7 N load. The improvements in tribological properties are primarily attributed to increased plasticity and surface oxidative ability, resulting from the hydrogen absorption during chemical reactions. Thus, AT offers a practical and effective way to significantly enhance the tribological performance of amorphous alloys.

Fabrication and Tribological Properties of Epoxy Nanocomposites Reinforced by MoS2 Nanosheets and Aligned MWCNTs.

The epoxy nanocomposites reinforced by MoS2 nanosheets and aligned multi-walled carbon nanotubes (MWCNTs) were fabricated by DC electric field inducement. The epoxy nanocomposites achieved improvement in the tribological properties with the addition of randomly dispersed MoS2 and MWCNTs compared to the pure epoxy. Furthermore, the epoxy nanocomposites exhibit anisotropic tribological and mechanical properties when the MWCNTs are aligned in the composites. The tribological properties of epoxy nanocomposites containing 1 wt% MoS2 and aligned 1.2 wt% MWCNTs achieved the maximum improvement when the sliding direction is perpendicular to the axial direction of MWCNTs. Compared to random MoS2 nanosheets and random MWCNTs reinforced epoxy nanocomposites, the friction coefficient and wear rate of random MoS2 and aligned MWCNTs reinforced epoxy nanocomposites decreased by 11.3 and 66.7% under a load of 5 N, respectively. The increased thermal conductivity and mechanical properties, higher surface content of nanoparticles, as well as unique alignment mode of MWCNTs are considered to be the main reasons for the improvement of tribological properties of epoxy nanocomposites.

Improvement of Tribological Properties and Corrosion Resistance of AISI 4340M Steel by Shot Peening and Plating Technologies

Improvement of Tribological Properties and Corrosion Resistance of AISI 4340M Steel by Shot Peening and Plating Technologies

Structural evolutions and tribological properties of laser cladded FeCoNiCrMo high-entropy alloy coating by laser remelting and tempering process: TEM and DFT calculations

A laser cladded FeCoNiCrMo high-entropy alloy (HEA) coating was treated by laser remelting and tempering process in sequence to improve its tribological properties. The morphologies, phases and nanostructures of obtained coatings were analyzed using a scanning electron microscope, X-ray diffraction and transmission electron microscope. The effects of laser remelting and tempering process on the tribological properties were investigated by a ball-on-disc wear tester, and the wear mechanism was revealed with the density functional theory calculation. The results show that the main crystal planes of laser cladded, laser remelted and tempering processed HEA coatings are transformed from (200) and (220) to (111), and the reduced free energy and differential charge density of crystal plane (111) contribute to the improvement of tribological properties on the HEA coatings.

Improvement in Tribological Properties with Addition of Hexagonal Boron Nitride (h-BN) and Molybdenum Disulfide (MoS2) Nanoparticles in Aerospace Lubricants

In the aircraft mounted accessory gearbox and gas turbine engine gearbox, a significant rise in temperature of lubricant was consistently observed due to the high coefficient of friction (COF) between the moving parts. This phenomenon limits the speed and power transmission of the gearbox. To resolve this, the current study recommends adding specific nanoparticles (NP) as an additive to the military (MIL) grade lubricant to reduce frictional resistance between the gears. Surfactants were also added to hexagonal boron nitride (h-BN) and molybdenum disulfide (MoS2) nanolubricants (NL) to improve NP suspension. Tribological investigations were conducted with a four-ball tester, a shear stability tester, and a Reichert tester to examine the lubricants. During the four-ball test, the wear scar diameter (WSD) on the specimen decreased by 16.73% and 12.3% with h-BN and MoS2 NL, respectively, compared to the results obtained using the base lubricant (BL). In the shear stability test, h-BN NL demonstrated 93%, and MoS2 NL demonstrated 67% more shear stability than the BL, while the COF was reduced by 13% in both h-BN and MoS2 NLs during the Reichert test. These test results prove that h-BN and MoS2 NPs, when added to a MIL standard BL, can demonstrate improved tribological capabilities even at extreme operational conditions.

Improving frictional and insulation performance with silica-coated titanium dioxide additives in grease

PurposeThe purpose of this study was to synthesize composite nanoparticles (TiO2@SiO2) via the chemical deposition method and investigate their efficacy as additives in polytetrafluoroethylene (PTFE) lubricating grease. The focus was on examining the frictional and conductive properties of the TiO2@SiO2 grease using a friction tester.Design/methodology/approachComposite nanoparticles (TiO2@SiO2) were synthesized using the chemical deposition method and incorporated into PTFE grease. Frictional and conductive properties were evaluated using a friction tester. Surface morphology and chemical composition of wear tracks were analyzed using scanning electron microscope and X-ray photoelectron spectroscopy, respectively.FindingsIncorporating TiO2@SiO2 at a mass fraction of 1 Wt.% led to a significant reduction in friction coefficient and wear width. The wear depth exhibited a remarkable decrease of 260%, while the contact resistance reached its peak value. This improvement in tribological properties could be attributed to the presence of TiO2@SiO2, where TiO2 served as the core and SiO2 as the shell during the friction process. The high hardness of the SiO2 shell contributed to enhanced load-bearing capacity. In addition, the exceptional insulation properties of SiO2 demonstrated excellent electron-capturing capabilities, resulting in improved friction and insulation performance of the TiO2@SiO2 lubricating grease.Originality/valueThis study demonstrates the potential of TiO2@SiO2 composite nanoparticles as additives in lubricating greases, offering improved friction and insulation performance. The findings provide insights into the design of advanced lubricating materials with enhanced tribological properties and insulation capacity, contributing to the development of more efficient and durable lubrication systems.

Tribological behaviour of microindented 100Cr6 steel surfaces in dry contact conditions

In the present work, we studied the dry tribological behaviour of a 100Cr6 steel, the spherical surface of which was texturized with microindentation. The purpose of adopting a mechanical indentation technique on a non-planar surface was to simultaneously evaluate the effectiveness of adopting a fast, deformation-based technique for improving the contact tribological properties. Specifically, dimples were created using an automatic microhardness tester equipped with a Vickers indenter, setting a load of 0.5 N. Friction tests were performed at different speeds considering textured surfaces with two different void ratios (VRs). Textured and untextured surfaces were tested using a ball-on-disc tribometer. In addition, the effect of dimple size was evaluated by producing Vickers indented surfaces at a load of 5 N per each indentation, while keeping the VR values unchanged and testing the frictional properties of such surfaces at a fixed speed of 4.18 mm/s. Textured surfaces were deeply investigated to motivate the improvement of tribological properties. Notably, compared to the untextured samples, the microindented samples exhibited a much lower coefficient of friction (COF), with a friction reduction compared to the untextured case ranging from 45 to 65%, depending on the VR values. The adoption of large dimples allowed the reduction of the COF, already at smaller VR value but, in such a case, the presence of bulges at the edge of the dimple worsens the wear resistance of the counter surface. In addition to reducing the contact area and the capability to trap any debris in the dimples, the local measurement of strength allowed to clarify that the friction reduction is also determined by the work hardening effect produced by the microindentation texturing. Considering the significant improvements recorded in terms of COF and the high ability to indent even non-planar surfaces, the proposed approach can be considered very promising and, therefore, industrially applicable (e.g. using a specifically designed multi-indenter tool) to affect the friction behaviour of components, even locally, during both their use and their production.

TiN/TiO2 composite coatings: preparation, microstructures and tribological properties

In our present work, TiN suspension was sprayed onto the 316 stainless steel substrate using the suspension high velocity oxy fuel thermal spray. An in-situ reaction between TiN and O2 occurred during the spray process to form TiO2 and TiN/TiO2 composite coatings were fabricated. The phase evolution, microstructures and tribological properties of TiN/TiO2 composite coatings were studied. Results showed that the interface between the coating and the substrate was well bonded, which was mainly owing to the in-situ reaction heat and the sufficient deformation of particles. The structure of molten particles, small grain size and low porosity could contribute to improving the mechanical and tribological properties of the in-situ coating. A schematic exfoliation process of TiN/TiO2 composite coating was proposed to analyze the failure of coatings. The antiwear mechanisms of the TiN/TiO2 composite coatings were discussed. The good cohesive bonding strength and high hardness of the TiN/TiO2 composite coating, the pinning role of TiN in crack propagation, and the newly formed TiO2 in the friction layer during the sliding test contributed to the improvement of tribological properties for the TiN/TiO2 composite coating. This work could provide a reference for the application of TiN/TiO2 composite coating in the field of friction and wear.

Nanosecond laser-induced dimple texturing of TB6 alloy surfaces: Tribological behavior under dry and starved-oil lubrication

This study investigates the improvement of tribological properties of TB6 (Ti-10V-2Fe-3Al) alloys through laser surface texturing. It examines the effects of laser scanning cycles (LSCs) and dimple spacing (DS) on the water contact angle and the coefficient of friction (CoF) under both dry friction and starved-oil lubrication conditions. Dimple-textured surfaces reduce wear and friction by decreasing the actual contact area between the friction pairs, preventing wear particle entrapment, and enhancing oil retention, thereby leading to stable oil films. The optimal LSCs and DSs significantly reduce the CoF by up to 66 % under dry friction conditions and by 61 % under starved-oil lubrication conditions, compared to original surfaces. Surfaces with increased LSCs and decreased DSs become superhydrophobic after octadecyltrichlorosilane modification.

Preparation and self-lubricity investigation of CNTs/Ni composite coatings under severe conditions

Carbon nanotubes (CNTs) demonstrate the potential to improve the tribological properties of nanocomposite coatings. Herein, CNTs/Ni composite coatings were quickly fabricated by the direct current (DC) electrodeposition. The adhesion strength was estimated by the scratch test incorporation with an acoustic emissive signal. Much attention was paid on the self-lubricity of the CNTs/Ni composite coating under severe conditions. Results indicated that presence of CNTs enhanced the adhesion strength of the pure Ni coating. Notably, CNTs contributed towards 54.5 % of friction reduction in comparison to the pure Ni coating at dry friction. The improvement of tribological properties was attributed to that under high contact stress the embedded CNTs were crushed to tiny lubricating particles and produced protective film on rubbing surfaces.

Tribological, magnetic and electric properties of magnetic polymer composites for airgap-less application

The development of electric machines necessitates the development solutions with efficiency. One possible solution is airgap-less devices. For this purpose, it is necessary to develop materials with favorable magnetic and tribological applications. The following work presents the production method and performance examination of tribological polymer magnetic composites. Samples were subjected to microscopic examination to determine the morphology of the composite. Tribological and magnetic properties were measured to determine the filler effect on the basic material parameters. Electrical parameters were also examined to determine possible electromagnetic losses in the material. The greatest increase in magnetic permeability was observed for the iron magnetic filler. The greatest improvement in tribological properties was observed for the graphite tribological filler.

Effect of milling time on structural, mechanical and tribological behavior of a newly developed Ti-Ni alloy for biomedical applications

Ti-Ni alloy is the most attractive material in the medical field for orthopedic implants like total hip replacement due to its special properties. The purpose of this study was to examine the impact of grinding/milling times on the characteristics of the nanostructured Ti50-Ni50 alloys produced via the mechanical alloying process (MA), utilizing a planetary high-energy ball mill at different grinding times (2, 6, 12, and 18 h). The grinding time causes grain refinement and a decrease in the porosity of materials, which allows for the improvement of a material’s mechanical properties and wears resistance. The structural, physical and tribological behavior of Ti50-Ni50 alloy was characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), nanoindentation test, and ball-on-disk tribometer operated under varying applied loads of 2, 10, and 20 N. The findings demonstrated that the crystallite size was reduced and the microstrain increased reaching values of 29 nm, and 0.99%, respectively, at higher grinding times. The percentage of porosity in the Ti50-Ni50 alloy was 11%, while the density attained was 89% after 18 h of grinding. Moreover, as the grinding duration increased up to 18 h, the hardness increased (341 HV) owing to the refinement of the grains. It was also noted that the Ti50-Ni50 alloy that was milled at 2 h exhibited the lowest elastic modulus (89 GPa). In addition, it was found that wear rates and the coefficient of friction were decreased reaching the values of 29.67 µm3/N.μm, and 0.31, respectively, for the samples milled at 18 h and examined under 2 N. Enhanced structural and mechanical qualities are responsible for this improvement in tribological properties. These properties make Ti50-Ni50 alloys clinically relevant for human biomedical implantation.

Thermal Properties of Engine Oils through the Integration of Graphene Nanoparticles: A Greener Approach for Sustainable Mechanical Systems

Tribology is a high demand mechanical system with friction and wear. Mechanical systems lose efficiency as a result. One answer for this issue is to utilize an oil that can limit contact and wear, bringing about improved effectiveness. The advancement of effective lubricating added substances for tribological properties improvement and improved thermal conductivity has gotten huge modern and scholarly consideration. By and large, nano-sized particles scattered in lubricants, referred to as nano-based lubricant, are utilized in mechanical structures to lessen heat and forces of frictions. Moreover, new guidelines will empower the utilization of greener lubrication advancements in oils. To resolve this issue, lubricants should satisfy guidelines while able to give exceptional oil characteristics. As another green material, this research will investigate the dissolving of Graphene nanoparticles in lubricants. The objective of this study is to perceive what Graphene added 10W40 motor oil means for the thermal properties and tribological characteristics. Graphene, which was added to 10W40 lubricant, was used to study the best design. Graphene nanoparticles were distributed in baseline engine oil in a two-step process. In the preparation of Graphene-based motor oil with a low volume mixture in the scope of 0.01% to 0.07% was used. Thermal conductivity and viscosity are estimated for all volume mixtures. Testing uncovered that Graphene added 10W40 motor oil were steady all through the review, with very little deposits in the following 30 days. The thermal conductivity of Graphene in SAE 40 motor oil expanded as the volume mixture is added.

Laser Surface Texturing: Characteristics and Applications

Abstract Laser surface texturing (LST) has emerged as a versatile and efficient technique for modifying surface properties across various materials. This paper provides an analysis of the characteristics and diverse applications of laser surface texturing. The paper begins by explaining the fundamental principles underlying LST, highlighting the mechanisms involved in material interaction and the resultant surface modifications. It explores the influence of laser parameters such as pulse duration, energy density, and wavelength on the texturing process, emphasizes their impact on surface morphology, roughness, and topographical features. Furthermore, this paper delves into the wideranging applications of LST across different industries and fields. It examines how LST enhances surface functionalities, including improvements in tribological properties, wettability, friction reduction, and biocompatibility. Additionally, the utilization of LST for creating microstructures enabling advanced functionalities in optics, electronics, biomedical devices, and energy harvesting systems is discussed. Moreover, the challenges and future directions in LST technology are highlighted, which encompass advances in precision, scalability, and integration of LST with other manufacturing processes. The potential environmental implications and economic feasibility of LST are also discussed. In summary, this paper examines the characteristics, applications, challenges, and future prospects of laser surface texturing, showcasing its significance as a promising technology for tailoring surface properties across diverse materials and industries.

Mechanical and antibacterial properties of hybrid polymers composite reinforcement for biomedical applications

This research investigates the biocompatibility, mechanical strength, and tribological properties of a hybrid composite material composed of high-density polyethylene (HDPE), hydroxyapatite (HAp), and titanium dioxide nanoparticles (Ti ). The study explores the microstructural characteristics of the composite material using scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD). Samples of HDPE-30%HAp with varying concentrations of Ti (5, 10, 15, and 20%) were prepared and extruded using a twin-screw machine. The hybrid composite materials underwent mechanical tests (tensile, flexural, and hardness), tribological tests (friction and wear rate), and antibacterial tests (resistance to Escherichia coli and Staphylococcus aureus bacteria). The results indicate that the optimal hybrid composite sample was HDPE-30%HAP-10% Ti , which demonstrated excellent mechanical properties (maximum tensile strength of 25.93 MPa and young modulus of 480 MPa) and a low coefficient of friction (COF∼ 0.07) while achieving high wear resistance (wear rate in the order of 1m ). The study shows that the improvement in mechanical properties results in a corresponding improvement in tribological properties. The antibacterial tests revealed that the hybrid composite material exhibited resistance to E. coli and S. aureus bacteria. The findings of this study suggest that the HDPE-30%HAP-10% Ti composite is a promising material for use in biomedical applications due to its excellent biocompatibility and desirable mechanical and tribological properties. The study demonstrates the potential of reinforced hybrid composite materials in overcoming the disadvantages of monolithic and hybrid micro-composites and highlights the importance of investigating the microstructural, tribological, and mechanical strength characteristics of composite materials for biomedical applications.

Lubricity characteristics of edge and basal functionalized GO as PAO additives

It was studied that the dodecylamine was grafted to the edge (EGO) and basal (BGO) of graphene oxide by amidation and ring-opening reactions to study the effect of different reaction sites on the tribological properties of modified graphite oxide, respectively. The results showed that BGO and EGO were successfully synthesized by a controlled synthesis process. Dispersion experiments showed that GO was dispersed in water and BGO was dispersed in chloroform, while EGO formed a Pickering emulsion and showed amphiphilicity in the water/chloroform two-liquid phase system. Friction experiments showed that both additives improved the friction reduction of the base oil, while BGO showed a better one. The mechanism analysis showed that BGO and EGO participate in the tribochemical reaction, forming a dense carbon film and thus improving the tribological properties. It was also found that BGO and EGO participated in the cracking of base oil as tribocatalysts, which positively impacted the improvement of tribological properties.

Improvement in tribological properties of thrust plate of gear pump through flame spattering in diverse cooling medium

In the present research, the influence of flame hardening on the surface of a thrust plate with reference to the coefficient of friction (COF), wear rate and micro-hardness has been discussed. Dry sliding wear test results indicate the improvement in COF in the hardened sample (0.3) with olive oil cooling as compared to the parent surface (0.53). Optical profile analysis of the wear track shows a lower wear rate for the hardened samples with oil cooling as compared to the parent material. Micro-hardness of the flame-hardened surface increased from 80 HV0.5 to a maximum value of 132 HV0.5.

Differentiated SnSb grain size distribution for improved tribological properties of Babbitt alloy

PurposeThe grain size and grain distribution mode have a significant impact on the tribological properties of Babbitt alloy. The purpose of this paper is to study the effect of differentiated SnSb grain size distribution on the improvement of tribological properties of Babbitt alloy.Design/methodology/approachBabbitt (marked by babbitt-cr), with a differentiated SnSb grain size distribution, was fabricated using a selective zone laser surface treatment. Bare Babbitt with coarse SnSb grain was marked as babbitt-c, and Babbitt with refined SnSb grain was marked as babbitt-r. The microstructure, microhardness and wettability of specimens were tested. The tribological properties of babbitt-c, babbitt-r and babbitt-cr were evaluated under dry and lubricated conditions.FindingsThe microstructure transforms from single coarse SnSb grain distribution or single refined SnSb grain distribution to differentiated SnSb grain size distribution, as a result of selective zone laser surface treatment. Among three specimens of microhardness, babbitt-cr showed the highest microhardness. The lipophilicity property of babbitt-cr was better compared to babbitt-c. A mixture of coarse and refined grain is beneficial to improve the tribological properties of Babbitt alloy under dry condition. Furthermore, compared with babbitt-c, the wear resistance of babbitt-cr was enhanced under lubricated condition. However, the anti-wear property of babbitt-cr was not significantly improved relative to babbitt-r with an increase in the loads.Originality/valueThe study demonstrates that modulated different grain size alternating distribution modes can improve the tribological properties of Babbitt alloy.Peer reviewThe peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-09-2022-0259/

Zn2+-induced construction for highly dispersed ball-on-flake nanostructured ZIF-7/g-C3N4 nanoadditive towards improvement of tribological properties

Herein, the highly dispersed ball-on-flake nanostructured ZIF-7/g-C3N4 nanocomposites were successfully constructed by two-step approach, i.e. the electrostatic adsorption (the first step) and in-situ preparation(the second step). The composition and structure of ZIF-7/g-C3N4 nanocomposites were determined by a series of characterizations (such as XRD, FT-IR, TGA, Zeta potential, XPS, SEM, TEM, etc). The dispersibility and interface compatibility of ZIF-7/g-C3N4 nanocomposites in base oil (150SN) were intensively probed by Uv-vis spectra and optical microscope, demonstrating that the ZIF-7/g-C3N4 nanocomposites had a superior interface compatibility in oil. Furthermore, the tribological properties of ZIF-7/g-C3N4 nanocomposites as additives in base oil were detailedly evaluated on a four-ball friction tester. The experimental results showed that the ZIF-7/g-C3N4 nanocomposites at 0.05 wt% optimum adding content exerted the reduction by 46.85% of average friction coefficient and 48.74% of wear scar diameter, while exhibiting the improvement by 18.37% of bearing capacity in base oil. In terms of the characterizations of the worn surface (such as FESEM, 3D profile, elemental mapping, XPS, etc), the lubrication mechanism of ZIF-7/g-C3N4 nanocomposites were deeply discussed and proposed, are attributed to its good dispersibility in base oil, assuming the existence of synergistic lubrication.

The effect of nanolubrication on wear and friction resistance between sliding surfaces

PurposeStudies on this topic have shown the remarkable lubricating properties, viz. friction-reducing and anti-wear, of certain nanoparticles. This makes them potential candidates for replacing the lubrication additives currently used in automobile lubricants, especially because the latter is known to be pollutants and less efficient in some specific conditions. This has not gone unnoticed to professionals in the sector, including those commercializing these additives, the oil companies and the car industry, all of whom are following this burgeoning research area with keen interest. All of them are faced with the problem of providing lubricants that meet the needs of the technological evolution of engines while respecting ever-stricter environmental norms.Design/methodology/approachThe impact of copper oxide (CuO) and zinc oxide (ZnO) nanoparticles on the tribological properties of the SAE-40 pure diesel oil is studied in this paper. The two nanoparticles are not oxide or deteriorate with the base oil. The average size of CuO and ZnO nanoparticles is 40 and 20 nm, respectively. Nanoparticle concentrations of 0.1 Wt.%, 0.2 Wt.%, 0.3 Wt.%, 0.4 Wt.% and 0.5 Wt.% are tested using a pin-on-disk tribometer to evaluate their impact on friction and wear. The test is carried out at different loads and rotating speeds of 58.86 N and 300 rpm, 39.24 N and 500 rpm and 78.48 N and 900 rpm at room temperature, respectively.FindingsThe obtained results of the nanolubricants are compared with those of pure diesel oil in terms of % improvement in tribological properties. However, it is observed that an increase in the nanoparticle concentrations does not guarantee to enhance the tribological properties. Similarly, increasing the applied load and the rotating speed does not lead to improving the anti-friction and anti-wear properties. The results obtained revealed that the optimal improvements in the anti-friction and anti-wear properties of the pure oil are 69% and 77% when CuO nanoparticle concentrations of 0.3 Wt.% and the ZnO nanoparticle concentrations of 0.1 Wt.% are used, where the applied load and rotating speed are 39.24 N and 500 rpm, respectively. It has also been noticed that the CuO nanolubricants have a significant impact on the anti-friction property compared with ZnO nanolubricants.Originality/valueAll these nanoparticles have been the subject of detailed investigation in this research and many key issues have been tackled, such as the conditions leading to these properties, the lubrication mechanisms coming into play, the influence of parameters such as size, structure and morphology of the nanoparticles on their tribological properties/lubrication mechanisms and the interactions between the particles and the lubricant co-additives. To answer such questions, state-of-the-art characterization techniques are required, often in situ, and sometimes an extremely complex set up. Some of these can even visualize the behavior of a nanoparticle in real time during a tribological test. The research on this topic has given a good understanding of the way these nanoparticles behave, and we can now identify the key parameters to be adjusted when optimizing their lubrication properties.Peer reviewThe peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-08-2022-0234/