Research

19 pages, 14764 KiB

Open AccessArticle

Tribofilm Formation and Friction Reduction Performance on Laser-Textured Surface with Micro-Grooved Structures

by Qianru Li, Renguo Lu, Hiroshi Tani, Shohei Kawada, Shinji Koganezawa, Xujun Liu and Peihong Cong

Lubricants 2024, 12(3), 91; https://doi.org/10.3390/lubricants12030091 - 13 Mar 2024

Viewed by 763

Abstract

Tribofilms, resulting from tribochemical reactions involving lubricants, additives, and metal surfaces, are pivotal in reducing friction, preventing adhesion, and minimizing wear. This study investigates the tribological characteristics of textured surfaces in boundary lubrication, emphasizing the impact of surface texturing on tribofilm formation. Untextured [...] Read more.

Tribofilms, resulting from tribochemical reactions involving lubricants, additives, and metal surfaces, are pivotal in reducing friction, preventing adhesion, and minimizing wear. This study investigates the tribological characteristics of textured surfaces in boundary lubrication, emphasizing the impact of surface texturing on tribofilm formation. Untextured surfaces manifest high friction coefficients and low wear owing to the development of thick tribofilms. However, debris accumulation impedes further tribochemical reactions, necessitating more energy for sliding and resulting in higher friction coefficients. Additionally, molybdenum dialkyl dithiocarbamate-derived MoS₂ oxidation diminishes the expected lubrication effect. Textured surfaces exhibit lower friction coefficients and higher wear because the structure aids debris removal, promoting the formation of thinner tribofilms. Despite increased wear from solid-to-solid contact, textured surfaces facilitate an early fluid lubrication transition and enhance cavitation capacity, leading to reduced friction coefficients. We also consider the impact of sliding direction angles on friction coefficients, revealing that lower angles parallel to the grooves heighten friction, whereas higher angles enhance cavitation capacity. Unexpectedly, a 90° sliding direction angle increases the friction coefficients, attributed to MoS₂ distribution in the tribofilms. These results provide crucial insights for optimizing lubrication strategies and enhancing wear resistance in boundary lubrication scenarios. Full article

(This article belongs to the Special Issue Advances in Surface Engineering and Tribology)

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17 pages, 8942 KiB

Open AccessArticle

Effect of Feedstock Powder Intrinsic Characteristics on the Tribological Behavior of Inductively Remelted NiCrBSi Flame-Sprayed Coatings

by Roxana Muntean, Petru-Cristian Vălean, Norbert Kazamer, Ion-Dragoș Uțu, Gabriela Mărginean and Viorel Aurel Șerban

Lubricants 2023, 11(9), 363; https://doi.org/10.3390/lubricants11090363 - 26 Aug 2023

Cited by 2 | Viewed by 870

Abstract

Ni-based alloys are among the materials of choice in developing high-quality coatings for ambient and high-temperature applications that require protection against intense wear and corrosion. The current study aims to develop and characterize NiCrBSi coatings with high wear resistance and improved adhesion to [...] Read more.

Ni-based alloys are among the materials of choice in developing high-quality coatings for ambient and high-temperature applications that require protection against intense wear and corrosion. The current study aims to develop and characterize NiCrBSi coatings with high wear resistance and improved adhesion to the substrate. Starting with nickel-based feedstock powders, thermally sprayed coatings were initially fabricated. Prior to deposition, the powders were characterized in terms of microstructure, particle size, chemical composition, flowability, and density. For comparison, three types of powders with different chemical compositions and characteristics were deposited onto a 1.7227 tempered steel substrate using oxyacetylene flame spraying, and subsequently, the coatings were inductively remelted. Ball-on-disc sliding wear testing was chosen to investigate the tribological properties of both the as-sprayed and induction-remelted coatings. The results reveal that, in the case of as-sprayed coatings, the main wear mechanisms were abrasive, independent of powder chemical composition, and correlated with intense wear losses due to the poor intersplat cohesion typical of flame-sprayed coatings. The remelting treatment improved the performance of the coatings in terms of wear compared to that of the as-sprayed ones, and the density and lower porosity achieved during the induction post-treatment had a significant positive role in this behavior. Full article

(This article belongs to the Special Issue Advances in Surface Engineering and Tribology)

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19 pages, 4780 KiB

Open AccessArticle

Prediction of Thrust Force and Torque for High-Speed Drilling of AL6061 with TMPTO-Based Bio-Lubricants Using Machine Learning

by Pramod Kathmore, Bhanudas Bachchhav, Somnath Nandi, Sachin Salunkhe, Palanisamy Chandrakumar, Emad Abouel Nasr and Ali Kamrani

Lubricants 2023, 11(9), 356; https://doi.org/10.3390/lubricants11090356 - 23 Aug 2023

Viewed by 1038

Abstract

This study was designed to examine the effects of a trimethylolpropane trioleate (TMPTO)-based lubricant on thrust force and torque under the high-speed drilling of Al-6061 as an effective environmentally friendly cutting fluid. The tribological performance of three lubricant blends was evaluated based on [...] Read more.

This study was designed to examine the effects of a trimethylolpropane trioleate (TMPTO)-based lubricant on thrust force and torque under the high-speed drilling of Al-6061 as an effective environmentally friendly cutting fluid. The tribological performance of three lubricant blends was evaluated based on ASTM standards. TMPTO base oil, notably enhances load-carrying capacity under extreme pressure conditions, with a seizer load of 7848 N. The best-performing oil was further optimized using a Taguchi-based design experiment to investigate the effect of different additive concentrations on thrust force and torque under actual contact conditions. Experiments were conducted using three critical machining parameters: additive concentration, spindle speed, and feed rate. The results of the ANOVA analysis reveal that spindle speed contributes most substantially (62.99%) to torque, with feed rate (23.72%) and additive concentration (7.74%) also showing significant impacts. On the other hand, thrust force is primarily influenced by feed rate (73.52%), followed by spindle speed (16.82%), and additive concentration (6.28%). Furthermore, a machine learning model was developed to predict and compare a few significant aspects of high-speed drilling machinability, including thrust force and torque. Three different error metrics were utilized in order to assess the performance of the predicted values, namely the coefficient of determination (R2), mean absolute percentage error (MAPE) and mean square error (MSE), which are all based on the coefficient of determination. Compared to other models, decision tree produces more accurate prediction values for cutting forces. The present study provides a novel approach for evaluating the most promising biodegradable lube oils and predicting cutting forces by formulating a perfect blend. Full article

(This article belongs to the Special Issue Advances in Surface Engineering and Tribology)

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18 pages, 8396 KiB

Open AccessArticle

The Effect of Steel Electropolishing on the Tribological Behavior of a Steel–Bronze Pair in the Mixed and Boundary Lubrication Regimes

by Robert Mašović, Daniel Miler, Ivan Čular, Suzana Jakovljević, Mario Šercer and Dragan Žeželj

Lubricants 2023, 11(8), 325; https://doi.org/10.3390/lubricants11080325 - 01 Aug 2023

Viewed by 725

Abstract

Electropolishing at high current densities without agitation of the electrolyte results in a pitting phenomenon that produces dimple-like surface features. Although pitting is unfavorable in the electropolishing process, its effect on surface modification, such as surface texturing, has not been thoroughly investigated. Surface [...] Read more.

Electropolishing at high current densities without agitation of the electrolyte results in a pitting phenomenon that produces dimple-like surface features. Although pitting is unfavorable in the electropolishing process, its effect on surface modification, such as surface texturing, has not been thoroughly investigated. Surface topography and chemical composition analyses of electropolished steel revealed surface pits and an oxide surface layer, indicating the presence of surface texture and coating. The resulting surface is characterized by negative skewness and high kurtosis values. The tribological behavior of the electropolished steel-bronze pair is investigated by evaluating coefficients of friction and bronze wear using sliding tests conducted in mixed and boundary lubrication regimes. The results are compared to those of the ground steel-bronze pair. In the mixed and upper range of the boundary lubrication regime, coefficients of friction reduction up to 30% and shorter running-in phases are observed for electropolished steel (electropolished steel μ_avg = 0.019 vs. ground steel μ_avg = 0.028). In contrast, the coefficient of friction increased in the lower range of boundary lubrication regime by 50% (electropolished steel μ_avg = 0.098 vs. ground steel μ_avg = 0.065). Electropolishing, as a cost- and time-effective method applicable to complex geometries, presents an alternative method for achieving surface modifications aimed at friction reduction and improved tribological behavior for non-conformal contacts in the boundary and mixed lubrication regimes. Full article

(This article belongs to the Special Issue Advances in Surface Engineering and Tribology)

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26 pages, 10408 KiB

Open AccessArticle

Impact of Temperature Variation on Friction Behaviour of Rare Earth-Doped Diamond-like Carbon Coatings with Ionic Liquid Lubricants

by Shahsharif Shaikh, Takeru Omiya, Albano Cavaleiro, Luis Vilhena, Amilcar Ramalho and Fábio Ferreira

Lubricants 2023, 11(7), 302; https://doi.org/10.3390/lubricants11070302 - 20 Jul 2023

Cited by 3 | Viewed by 1099

Abstract

This research paper investigates the tribological performance of diamond-like carbon (DLC) coatings doped with rare earth metals (europium and gadolinium) as well as pure DLC lubricated with ionic liquid additives (trihexyltetradecylphosphonium bis(2-ethylhexyl) phosphate {[P₆₆₆₁₄][DEHP]} and 1-ethyl-3-methylimidazolium diethyl phosphate {[EMIM][DEP]}) in Polyalphaolefin [...] Read more.

This research paper investigates the tribological performance of diamond-like carbon (DLC) coatings doped with rare earth metals (europium and gadolinium) as well as pure DLC lubricated with ionic liquid additives (trihexyltetradecylphosphonium bis(2-ethylhexyl) phosphate {[P₆₆₆₁₄][DEHP]} and 1-ethyl-3-methylimidazolium diethyl phosphate {[EMIM][DEP]}) in Polyalphaolefin 8 (PAO8). The study aims to examine the effect of temperature on the interaction between the coatings and additives by conducting tribological experiments using a block-on-disk setup at temperatures of 60 °C, 80 °C, and 100 °C. The primary objective is to evaluate the performance of doped DLC coatings compared to pure DLC coatings with ionic liquid additives in the lubricant in boundary lubrication conditions at various high working temperature environments. The experiments reveal that doped DLC coatings with ionic liquid additives exhibit superior tribological performance compared to pure DLC coatings. The rare earth metal dopants play a positive role in the formation of a tribofilm on the surface of the coatings as it interacts with ionic liquids, resulting in a lower coefficient of friction (CoF). Temperature influences the performance of the coatings and additives. The CoF increases with temperature for pure DLC coatings, while for doped DLC coatings it was significantly less. These findings highlight the influence of temperature on the tribological behavior of DLC coatings. Overall, this study contributes valuable insights into the impact of rare earth metal dopants and ionic liquid additives on the tribological performance of DLC coatings under different temperature conditions. The results demonstrate the potential of utilizing doped DLC coatings with ionic liquid additives as an effective approach to enhance the performance of mechanical systems. Full article

(This article belongs to the Special Issue Advances in Surface Engineering and Tribology)

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15 pages, 4032 KiB

Open AccessArticle

Wear Performance of Cu–Cd, Cu–Be and Cu–Cr–Zr Spot Welding Electrode Materials

by Bhanudas D. Bachchhav, Shrikant V. Chaitanya, Sachin Salunkhe, Palanisamy Chandrakumar, Marek Pagáč and Emad Abouel Nasr

Lubricants 2023, 11(7), 291; https://doi.org/10.3390/lubricants11070291 - 11 Jul 2023

Cited by 1 | Viewed by 1181

Abstract

Heating of the electrode at the work–piece interface zone in spot welding, leading to degradation of the tip, becomes a significant concern in the high-volume production automotive industry. By recognizing the interrelationship between hardness, wear resistance, and thermal conductivity, the authors emphasize the [...] Read more.

Heating of the electrode at the work–piece interface zone in spot welding, leading to degradation of the tip, becomes a significant concern in the high-volume production automotive industry. By recognizing the interrelationship between hardness, wear resistance, and thermal conductivity, the authors emphasize the importance of selecting electrode materials with suitable alloying elements desirable for achieving optimal performance in spot welding applications. This paper studies the wear behaviour of three types of spot-welding electrode materials under dry sliding contact conditions. A pin-on-disc tester was used to investigate Cu–Cd, Cu–Be and Cu–Cr–Zr alloys’ wear behaviour under variable parametric load, temperature and time conditions. Taguchi L9 orthogonal array was used to investigate the significance of parameters and their effect on linear wear. The ranking of the parameters was performed using SN ratio analysis. The wear mechanism was also studied using SEM analysis. Abrasive wear was observed at lower loads, while adhesion, oxidation and plastic deformation were observed under high-load and -temperature conditions. This study suggests an alternative to the presently used electrolytic tough pitch (ETP) Cu electrode involving equally good wear-resistance material. However, a detailed investigation on the effect of plasma on the metallurgical characteristics of selected material is suggested. Full article

(This article belongs to the Special Issue Advances in Surface Engineering and Tribology)

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15 pages, 68257 KiB

Open AccessArticle

Research on the Tribological Behavior of Textured Cylindrical Roller Thrust Bearings with Different Distributions of Pits and Nylon Cages under Dry Condition

by Yazhe Chen, Risheng Long, Zhihao Jin, Chen Zhao and Ming Wang

Lubricants 2023, 11(4), 154; https://doi.org/10.3390/lubricants11040154 - 23 Mar 2023

Cited by 1 | Viewed by 1062

Abstract

Differing from the published documents on the effect of texture distributions of sliding tribo-pairs on their friction and wear properties, this study introduced eight patterns to reveal the influence of different distributions of pits on the tribological behavior of textured rolling element bearings [...] Read more.

Differing from the published documents on the effect of texture distributions of sliding tribo-pairs on their friction and wear properties, this study introduced eight patterns to reveal the influence of different distributions of pits on the tribological behavior of textured rolling element bearings with nylon cages under dry condition, namely: Outside-1/4 (OS1/4), Outside-1/2 (OS1/2), Outside-3/4 (OS3/4), Inside-1/4 (IS1/4), Inside-1/2 (IS1/2), Inside-3/4 (IS3/4), Bothside-1/3 (BS) and full (FP). A fiber laser marking system was used to prepare them on the raceways of the shaft washers of cylindrical roller thrust bearings (81107TN). A vertical universal wear test rig was used to obtain their coefficients of friction under an axial load of 2600 N and a rotating speed of 250 RPM, without any lubricant provided. Their wear losses and worn surfaces were characterized. The influence mechanism of different distributions on the tribological properties was also discussed. The results show that the self-lubricating performance of nylon cages can ensure the continuous operation (≥5 h) of cylindrical roller thrust bearings under dry condition. The influence of outside-distributed patterns on the friction and wear properties of bearings is significant. The friction-reducing effect and wear resistance of full textured group is improved but not the best. The friction-reducing and anti-wear behavior of OS1/2 is similar to that of FP. In this work, OS3/4 can provide the best tribological performance under self-lubricating conditions. Compared with the data of smooth bearings, its average coefficient of friction and wear loss can be reduced by 37.68% and 38.85%, respectively. This work would provide a valuable reference for the raceway design and reliability optimization of rolling element bearings. Full article

(This article belongs to the Special Issue Advances in Surface Engineering and Tribology)

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20 pages, 18897 KiB

Open AccessArticle

Tribological Behaviour and Microstructure of an Aluminium Alloy-Based g-SiC Hybrid Surface Composite Produced by FSP

by Jun Liang Tan and Kia Wai Liew

Lubricants 2023, 11(3), 124; https://doi.org/10.3390/lubricants11030124 - 10 Mar 2023

Cited by 3 | Viewed by 1362

Abstract

In this work, the microstructure and wear characteristics of a surface-reinforced composite based on an aluminium alloy with a mixture of graphene nanoplatelets (GNP) and silicon carbide (SiC), referred to as g-SiC, fabricated by Friction Stir Processing (FSP), are investigated. To further improve [...] Read more.

In this work, the microstructure and wear characteristics of a surface-reinforced composite based on an aluminium alloy with a mixture of graphene nanoplatelets (GNP) and silicon carbide (SiC), referred to as g-SiC, fabricated by Friction Stir Processing (FSP), are investigated. To further improve the tribological performance, different volume fractions (0 vol%, 5 vol%, 10 vol% and 15 vol%) of g-SiC-reinforced aluminium alloy are prepared by FSP. It is concluded that the Friction Stir Processed (FSPed) AA5083/g-SiC (15 vol%) specimen has optimum reduction in average friction coefficient (61.13%) and optimum reduction in specimen weight (72.97%). In summary, such hybrid reinforcements effectively improve the mechanical and tribological properties of metals with minimal negative impact on the environment and humans, while reducing material loss and overall manufacturing costs. Full article

(This article belongs to the Special Issue Advances in Surface Engineering and Tribology)

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27 pages, 4768 KiB

Open AccessArticle

Tribological and Mechanical Properties of the Nanostructured Superlattice Coatings with Respect to Surface Texture

by Ernests Jansons, Janis Lungevics, Uldis Kanders, Armands Leitans, Guna Civcisa, Oskars Linins, Karlis Kundzins and Irina Boiko

Lubricants 2022, 10(11), 285; https://doi.org/10.3390/lubricants10110285 - 28 Oct 2022

Cited by 5 | Viewed by 1450

Abstract

Ceramic Nanostructured Superlattice Coatings (NSC) have broad applicability to improve the parts’ and assemblies’ tribological and mechanical properties for the needs of the automotive and aerospace industries. Improving the material properties using nanocoatings for such a widely used material as, for example, bearing [...] Read more.

Ceramic Nanostructured Superlattice Coatings (NSC) have broad applicability to improve the parts’ and assemblies’ tribological and mechanical properties for the needs of the automotive and aerospace industries. Improving the material properties using nanocoatings for such a widely used material as, for example, bearing steel 100Cr6 makes it possible to improve the service life of machine parts. In this paper, the correlation dependence between tribological and mechanical properties of the NSC and its surface texture are considered to determine how much surface texture will affect the tribological performance of the coated workpieces, as well as the measuring and evaluation procedure of the nanocoatings, are presented. Three different NSC described by a general empirical formula {TiMe1Me2-CN/TiAlSi-N}n and based on the modified carbonitride/nitride non-stoichiometric chemical composition were created, and their tribological and mechanical properties measured and analyzed in the context with surface texture. NSC deposited by the advanced PVD (Physical vapor deposition) technique demonstrated significantly higher wear resistance (up to 28 times), reasonably lower friction coefficient (CoF) (up to 4 times), and significantly higher hardness of the coated workpieces (up to 7 times) versus substrate material. A strong correlation between the steady-state dry sliding friction, CoF, and the amplitude and functional surface texture parameters of tribo-track were observed. The first results of the initiated research regarding the correlation analysis of the tribological and mechanical properties, on the one hand, and surface texture, on the other hand, of the NSC are reported here. Full article

(This article belongs to the Special Issue Advances in Surface Engineering and Tribology)

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17 pages, 4620 KiB

Open AccessArticle

Correlation between the Mechanical and Tribological Properties of Rutile Reinforced LM27 Alloy Composite

by Pardeep Kumar Nagpal, Suresh Kumar, Jagmohan Datt Sharma, Sunil Kumar Mahla, Sachin Salunkhe and Hussein Mohamed Abdelmoneam Hussein

Lubricants 2022, 10(10), 251; https://doi.org/10.3390/lubricants10100251 - 11 Oct 2022

Viewed by 1260

Abstract

To meet the global requirements of the industry, there is a need for innovative light weight, low cost, eco-friendly, high quality engineering materials with superior performance at a wide range of temperatures. Aluminum Matrix Composites (AMCs) are lightweight materials with isotropic properties, a [...] Read more.

To meet the global requirements of the industry, there is a need for innovative light weight, low cost, eco-friendly, high quality engineering materials with superior performance at a wide range of temperatures. Aluminum Matrix Composites (AMCs) are lightweight materials with isotropic properties, a suitable choice for modern industry. Low-cost aluminum alloys reinforced with minerals have found a special place in the automotive industry for the manufacture of automobile parts. Rutile particles improve the mechanical properties of the aluminum matrix, making it attractive for structural applications as well as providing greater wear resistance to the composite during sliding. In the present studies, a rutile mineral reinforced LM27 aluminum alloy composite was developed through a stir casting route with 6, 9 and 12 wt.% reinforcements. To study the effect of particle size on the mechanical and tribological properties of composite samples reinforced with fine-sized (50–75 μm) and coarse-sized (106–125 μm) rutile particles were prepared From the results of the experiment, it was found that the hardness, compressive strength and wear resistance increase with increasing rutile wt.% addition. The worn surface and re-groove of the new surface are restored during sliding with the help of oxide films. The analysis of the fractured surface clearly indicates with the help of energy dispersive X-ray spectroscopy (EDS) that with the increase in the volume fraction of the reinforced particles, the porosity increases, which could be the main reason for the compression failure of the composite material. Full article

(This article belongs to the Special Issue Advances in Surface Engineering and Tribology)

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15 pages, 8573 KiB

Open AccessArticle

Effect of the Applied Voltages on the Corrosion–Wear Behavior of Thermal Spray Al Coating

by Shun-Yi Jian, Hung-Hua Sheu, Jun-Kai Chang, Chih-Hung Chen, Yuan-Huan Hong, Ming-Hsun Lin and Hung-Bin Lee

Lubricants 2022, 10(8), 197; https://doi.org/10.3390/lubricants10080197 - 22 Aug 2022

Viewed by 1441

Abstract

In this work, an Al coating prepared using the arc spray process was carried out with a corrosion–wear analysis by a block-on-ring system. The interaction of corrosion and wear of coatings in seawater was also investigated. The effect of different corrosion potentials on [...] Read more.

In this work, an Al coating prepared using the arc spray process was carried out with a corrosion–wear analysis by a block-on-ring system. The interaction of corrosion and wear of coatings in seawater was also investigated. The effect of different corrosion potentials on the corrosion and wear of the coating was discussed, and the structure and corrosion products of the coating were observed by SEM. The results of dynamic potential polarization curves and friction coefficient measurements were used to clarify the corrosion and wear behavior of aluminum coatings in seawater. After quantitative analysis of a corrosion and wear test, it was found that with the increase in polarization potential, the total weight loss of corrosion and wear (W_total) of the aluminum coating increased significantly. This means that the corrosion–wear interaction accounts for most of the weight loss of the coating. Full article

(This article belongs to the Special Issue Advances in Surface Engineering and Tribology)

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