Trap Wear Debris Research Articles

High-temperature tribological properties of AlCrN coatings deposited on textured surfaces under dry friction

Linear textures and AlCrN coatings were produced on cemented carbides using laser and physical vapor deposition, respectively. Reciprocal sliding friction studies were conducted under dry friction conditions to examine the tribological properties of the AlCrN coatings placed on textured surfaces against Si3N4 ceramic balls at various temperatures. The findings demonstrated that at friction temperatures of 200 °C, 400 °C, and 600 °C, the average friction coefficient of the AlCrN coating samples placed on textured surfaces was lower than that of the samples deposited on smooth surfaces. This reduction occurred by 9.6%, 15.1%, and 23.9%, respectively. Meanwhile, because micro-textures trap wear debris, AlCrN coating samples put on textured surfaces had lower surface adhesions, indicating that micro-textures can improve the tribological properties of AlCrN coatings. Finally, the mechanisms of micro-texture improving tribological properties were investigated. Micro-textures can store wear debris, reducing friction coefficients and thereby minimizing abrasive wear. Micro-textures, on the other hand, can prevent coating oxidation by lowering the temperature of the friction area, resulting in less oxidative wear.

Improvement of the tribological behavior of high reinforcement concentration Al–SiC (63%) metal matrix composite through laser surface texturing

The tribological performance of high reinforcement concentration AlSiC-9 Metal Matrix Composite (63% reinforcement) can be improved by laser texturing. This research performs different topographies by changing the energy density and scanning speed parameters, which modify the liquid retention and wear resistance. Results demonstrated a reduction of up to 60% in the friction coefficient and up to 70% in wear volume. SEM/EDX analysis identified adhesive, abrasive, and plastic deformation as the main wear mechanisms. These results confirm that the main contribution of textures was to improve the lubrication retention and trap wear debris.

Influence of Percolation effect of additives on the Performance of Conical Textured Porous Hybrid Journal Bearing

Textured bearing surfaces are widely used to reduce the friction in lubricated contacts. Besides the hydrodynamic pressure generated by the physical wedge, micro-textures act as micro-bearings and generates localized pressure. As a result, an additional load carrying capacity is generated. Further, micro-texture also serves as a lubricant reservoir, trapping wear debris and abrasive particles to improve the performance of tribo- pair. In this study, the effect of micro-textures and percolation effect of additives on the performance of hybrid conical porous journal bearings (HCPJBS) has been studied. The interactive effects of permeability parameter, spherical shaped micro-texture, semi cone angle and couple stress lubricant parameter considering the percolation effect parameter of additives on the performance of HCPJBS has been studied. FEM is used to numerically simulate the flow behaviour of couple stress lubricant in the bearing clearance space of a HCPJBS. The results shows that the HCPJBS operating with couple stress lubricant provides enhanced stability margin [Formula: see text] for lower values of permeability parameter [Formula: see text] and semi cone angle [Formula: see text].

Micro-dimple and micro-bulge textures:Influence of surface topography types on stick–slip behavior under starved lubrication

Stick-slip behavior, a common problem of contact under severe lubrication, is closely related with surface topography. To investigate the influence of surface topography types on stick–slip behavior, micro-dimple and micro-bulge textures, typical concave and convex topographies, were fabricated by pulse picosecond laser and CW fiber, respectively. A gyroscope sensor was mounted on the pin-on-disc modular of multifunctional tribometer to conduct friction dynamics tests. The intensity of stick–slip behavior is characterized by the amplitude and duration of stick–slip behavior. The results show that, under the same starved lubrication, the micro-bulge textured disc showed the lowest intensity while the untextured one showed the highest intensity. In comparison with micro-dimple and micro-bulge textured disc exhibits higher efficiency in inhibiting stick–slip behavior as well as starting stable sliding. The mechanism of inhibiting stick–slip behavior for micro-dimple textures is generated by trapping wear debris and forming effective oil film. However, the cause of micro-bulge textures is the reduced contact area, which result in the reduction of the propensity of secondary plateaus, plastic flow, and adhesive junctions between asperities.

Effects of a Cylinder Liner Microstructure on Lubrication Condition of a Twin-Land Oil Control Ring and a Piston Skirt of an Internal Combustion Engine

It is hypothesized that structured sliding-surfaces improve the lubrication condition by forming an oil sump on the sliding surface, redistributing the oil, and trapping wear debris. For these reasons, structured sliding-surfaces have been used as a friction reduction method for a long time. In this work, effects of microstructure laid on the cylinder liner of an internal combustion engine on twin-land oil control ring (TLOCR) and piston skirt lubrication condition were investigated by comparing friction between a conventional fine-honed liner (CFL) and a micro-structured liner with the CFL. The measurements using a floating liner engine showed that the microstructure improved lubrication condition by reducing hydrodynamic friction. On the other hand, it was also observed that the microstructure could result in elevated friction under certain engine operating conditions.Graphical Abstract

Surface textures fabricated by laser and ultrasonic rolling for improving tribological properties of TiAlSiN coatings

To enhance the tribological properties of the TiAlSiN coatings, two types of micro-textures were fabricated on the AISI 1045 steel substrates by laser texturing and ultrasonic rolling texturing prior to coating deposition. The mechanical properties and tribological behaviors of different samples were evaluated. Results revealed that the micro-textures improved the tribological properties of TiAlSiN coatings under dry friction and lubricant conditions. Under dry friction conditions, the friction coefficient and steel ball wear rate of the coatings decreased by ~16.9% and ~44.2%, respectively, after ultrasonic rolling texturing pretreatment, when compared with the coatings deposited on the polished substrates. Under lubricant conditions, the two values were reduced by ~27.8% and ~73.4%, respectively. The contribution of micro-textures was primarily to amplify lubrication, trap wear debris, decrease contact area and improve bearing capacity. The modification mechanism of the ultrasonic rolling texturing also benefited from the enhanced mechanical properties.

Characteristics of dimple structure on aluminium silicon alloy fabricated using turning machine

PurposeThis research aims to present the characteristics of dimple structure which was fabricated using a turning machine, where the characteristics include sizes, shapes, area ratio and aspect ratio. This research aims at filling the gap in the machining parameters of previous research in producing dimple by using turning process with the aid of dynamic assisted tooling for turning (DATT). In producing dimple, a carbide insert grade H1 was used on a hypereutectic aluminium silicon alloy (A390) material. Dimple has many advantages such as for reducing friction coefficient, load-carrying capacity and trap wear debris for sliding mechanical components.Design/methodology/approachThere are seven machining parameters (cutting speed, feed rate, depth of cut, frequency, amplitude, rake angle, relief angle and nose radius) which have an influence on dimple produced. Taguchi method (orthogonal arrays L8) was used to conduct the experiment systematically and efficiently for these seven parameters. A carbide insert grade H1 was used as a cutting tool on a turning machine with the aid of DATT. The dimple structure was fabricated on a cylindrical rod hypereutectic aluminium silicon alloy (A390). A profilometer 3D Alicona infinite focus and an optical microscope equipped with Vis software were used to analyse the fabricated dimple structure.FindingsVarious shapes and sizes of ellipse dimples were produced in this research, including short and long drops with lengths in the range of 517.03–3,927.61 µm, widths of 565.15–1,039.19 µm, depths of 14.46–124.87 µm, area ratios of 5.05–25.65% and aspect ratios of 0.007%–0.111%. There were four experiments within the optimal area ratio range of 10%–20%, i.e. the second, third, seventh and eighth experiments. The width of these dimples was 895.95, 961.39, 787.27 and 829.22 µm, length was 826.26, 3163.13, 885.98 and 1026.65 µm, depth was 83.67, 84.19, 87.05 and 110.70 µm and area ratio was 15.12%, 13.14%, 14.79% and 12.70%. The surface roughness of textured surface was below 1 µm. In this research, the results obtained were similar with that of previous researchers on dimple structure related to tribology performance.Originality/valueThere exists machining parameters, namely, cutting speed and frequency, that were not used by previous research in producing dimple. These machining parameters (cutting speed and frequency) were used in this research to produce dimple via turning process with the aid of DATT using carbide insert grade H1. The turning process is an environmentally friendly process which is suitable for mass production for fabricating dimple structure as compared to most of the current methods which are widely used in fabricating dimple structure.

Effect of Surface Modification on the Tribological Properties of Friction Blocks in High-Speed Train Brake Systems

Commercial high-speed train friction blocks with a hole in the middle of the surface and perforated blocks filled with additive materials are introduced in drag brake experiments conducted on a customized small-scaled braking dynamometer. These additive materials include Cu-based powder metallurgy material, composite material, and a Mn–Cu damping alloy. The results indicate that the filling materials significantly influence the wear behavior of a braking interface and the characteristics of friction-induced vibration. Under the same experimental conditions, the perforated blocks filled with different materials produce different types of wear debris and exhibit different wear evolutions, markedly changing the wear debris distribution and surface morphology. These changes lead to variations in thermal distribution on the surfaces of both the friction block and brake disc. The study also shows that as a filling material, the Mn–Cu damping alloy can suppress the friction-induced vibration of the brake system, resulting in the lowest level of brake noise among all brake systems. However, the original friction block (i.e., the block without any filling material) can trap wear debris because of its perforated structure. The structure produces less friction-induced vibration and noise, compared with the block filled with powder metallurgy material. The noise performance of the composite material block is superior to the noise performance of the block without any filling material (i.e., the original block) and the block with powder metallurgy material but inferior to that of the block filled with the Mn–Cu damping alloy. Finite element analysis indicates that the properties of the filling materials exert no effect on the unstable vibration intensity of the brake system. Therefore, the wear debris behavior of the filling materials and the interface wear characteristics influence the friction-induced vibration and noise of the brake system.

Effect of V-Groove Surface Pattern on the Tribological Properties of Epoxy

Epoxy is a polymeric material that is widely used in various fields as an adhesive, coating, and bulk material due to its outstanding properties. Many research studies on reinforced polymers have been conducted by adding micro/nanoparticles or fibers to attain better tribological properties. However, the tribological properties of patterning on the epoxy surface are relatively obscure. In this study, friction and wear properties of flat and V-groove patterned epoxy specimens were analyzed in dry and water lubricated sliding conditions to assess the effectiveness of the surface pattern in reducing friction and wear. It was found that under low applied force conditions in which the V grooves remained almost intact, the surface pattern contributed to decreasing the friction coefficient as much as 0.12 and increasing the stability of frictional behavior in dry sliding condition. This outcome was attributed to the ability of the grooves to trap wear debris inside the cavities. However, under water lubrication with polytetrafluoroethylene (PTFE) particles used as additives, the V-groove specimens were less effective in reducing friction due to the relatively small contact area. As the contact area increased, the effect of water lubrication with PTFE particles in reducing friction could be enhanced. These results are expected to serve as a fundamental basis for designing and fabricating the surface of polymeric components for tribological applications in dry and lubricated conditions.

Improving Tribological Performance of Inconel 625 by Combining Groove-Textured Surfaces with Sn-Ag-Cu Solid Lubricant

High wear is the primary failure mechanism of Inconel 625 in mechanical parts. The surface modification is workable method to improve tribological performance of Inconel 625. In this paper, the groove-textured surfaces with different widths and pitches were prepared on the surfaces of Inconel 625 by electrical discharge machining technology. The Sn-Ag-Cu solid lubricant was deposited on the grooves. The synergistic effects of Sn-Ag-Cu solid lubricant and groove-textured surface on the tribological performance of Inconel 625 were studied. Results show that the groove-textured surface of Inconel 625 filled with Sn-Ag-Cu solid lubricant shows the lowest friction. Compared with the untextured sample, the friction coefficients of groove-textured sample with the groove density of 20% and the groove-textured sample with the groove density of 25% filled by Sn-Ag-Cu are reduced 35% and 48%, respectively. The textures can trap wear debris under the dry sliding condition. In addition, Sn-Ag-Cu alloys filled in the grooves supply the sufficient lubricant at the contact interface during the sliding process. The lubricating film on the contact surface is formed gradually, which is mainly due to the shear adaptability and low melting point of Sn-Ag-Cu alloy. It shows that deposition of Sn-Ag-Cu solid lubricant coating on the groove-textured surface is an effective way for improving the friction and wear performance of Inconel 625.

Effect of Shape, Density, and an Array of Dimples on the Friction and Wear Performance of Laser Textured Bearing Steel under Dry Sliding

The present study is directed to reveal the effect of density and shape of the dimples on the friction and wear characteristics of textured bearing steel (100Cr6) under dry sliding conditions. One untextured and four laser-textured disks of 100Cr6 steel with circular and bi-triangular dimples having 7 and 20% density, respectively, in the spiral layout were tested using a pin-on-disk unidirectional tribometer against a 100Cr6 pin having a flat surface with rounded corners under flat-on-flat configuration. The tests were carried at different speeds of 0.2, 0.6, and 1 m/s at a constant load of 15 N. The results indicate that a higher density of bi-triangular dimples had less wear and a lower coefficient of friction compared to untextured disk or disk with circular dimples, particularly at a relatively higher speed. This has been attributed to a relatively higher number of dimples in the contact zone in case of a spiral array, which increases the entrapment of more wear particles leading to a reduction in wear. The friction coefficient had a relatively higher value at a relatively lower speed but decreased at the highest speed of 1.0 m/s used in the present study. The results suggest that dimples may not be too effective under dry contact because they lose their effectiveness to trap wear debris after getting filled.

Wear performance of electrohydrodynamically atomized WS2 coatings deposited on biomimetic shark-skin textured surfaces

Abstract This paper aims to provide a method in improving tribological properties of Al2O3/TiC ceramics. Biomimetic shark skin was produced on Al2O3/TiC ceramic surfaces by laser surface texturing. Then WS2 coating was deposited on the biomimetic skin by electrohydrodynamic atomization and its dry friction behaviours and wear mechanisms were investigated. Results revealed that the synergy effect of biomimetic shark skin and WS2 coatings has an effective influence on the tribological properties of Al2O3/TiC ceramics. The friction coefficient reduced to ∼0.3 and ∼0.07 after texturing biomimetic shark skin and depositing WS2 coatings, which reduced by 29% and 84%, respectively, compared with those of only polished Al2O3/TiC ceramics. The contribution of biomimetic shark skin was primarily decreasing the friction surface, reducing shear stress and trapping wear debris. Moreover, the grooves acted as lubricant reservoir could keep a thicker trio-film and realize continuous lubrication for a longer friction time.

Numerical Simulation and Experimental Analysis of Grease Friction Properties on Textured Surface

This research article is a numerical simulation study and experimental verification of the frictional behaviors of grease lubricated sliding contact under mixed lubrication conditions. The influences of surface texture parameters on the frictional properties were investigated. A numerical simulation model was specifically developed in MatLab which employs the average flow Reynolds equation established on the basis of finite-element analysis to compute the friction coefficient, pressure distribution, and film thickness. The results showed that friction coefficient is largely dependent on texture parameters with higher and lower dimple depths resulting in higher friction coefficient at a fixed dimple density. The sample with texture density of $$T_{\text{d}} = 15\%$$ and texture depth of $$H_{3} = 7$$ μm exhibited the best friction properties experimentally, because it can store more grease and trap wear debris. Through the comparison of the simulated results of the current model with the ring-on-disc experimental results, the validity of the mixed lubrication model was confirmed. However, the lowest friction coefficient occurs at dimple depth of 5 μm and texture density of 10% which is slightly at variance with the experimental results. The simulated results exhibit the reduction of friction for surface texturing and the main mechanism for such an effect may be attributed to the hydrodynamic pressure effect of the surface texturing, which increases the mating gap and reduces probability of asperity contact.

Comparison of the effect of typical patterns on friction and wear properties of chromium alloy prepared by laser surface texturing

Chromium alloy has been widely employed in industry due to high strength and corrosion resistance. However, poor tribological performance directly affect the lifetime of chromium-based components. In order to improve surface properties of chromium alloy, we investigate the effect of typical patterns including micro-dimples, micro-grooves and micro-grids on their friction and wear behaviors generated by laser surface texturing. Experimental results show that laser-textured surfaces significantly reduce the wear volume up to 57%, especially for surface patterns with micro-grids. The enhanced wear performance is mainly caused by the increased microhardness in local quenched zones, the capability of trapping wear debris and uniform stress distribution during friction sliding process.

Study on the Correlation Between Dynamical Behavior and Friction/Wear Mechanism Under the Effect of Grooves

In this work, the interfacial friction and wear and vibration characteristics are studied by sliding a chromium bearing steel ball (AISI 52100) over both multi-grooved and single-grooved forged steel disks (20CrMnMo) at low and high rotating speeds in order to reveal the effect mechanism of groove-textured surface on tribological behaviors. The results show that the grooves modify the contact state of the ball and the disk at the contact interface. This consequently causes variations in the normal displacement, normal force, and friction force signals. The changes in these three signals become more pronounced with increasing groove width at a low speed. The collision behavior between the ball and the groove increase the amplitude of vibration acceleration at a high speed. The test results suggest that grooves with appropriate widths could trap wear debris on the ball surface while avoiding a strong collision between the disk and the ball, resulting in an improvement in the wear states.

Influence of tribo-magnetization on wear debris trapping processes of textured dimples

Abstract The mechanism of attachment of wear debris to textured dimples was investigated experimentally. Textured dimples were fabricated on the surface of medium carbon steel specimen with drilling method. Reciprocating ball on disc sliding wear experiments were carried out. The dimples trapped with wear debris and worn surfaces were observed with microscope. Tribo-magnetization of wear debris was employed to explain the attachment of debris in dimples. The size of wear debris and magnetic flux density of worn surfaces were measured. Wear experiments processes were also carried out under degaussing conditions. The experimental results show that tribo-magnetization causes the phenomena of attachment and bridging of wear debris to edge of textured dimples. By applying degaussing method, attachment of wear debris within textured dimples can be reduced. For comparison, coefficients of friction, wear mass loss of specimens and wear volume loss of mating balls were measured under both conditions of non-degaussing and degaussing. Degaussing can be beneficial to improve the capacity of trapping wear debris of textured dimples for ferromagnetic materials, and to improve the wear resistance of dimple textured specimen.

Debris trapping and space-varying contact via surface texturing for enhanced noise performance

In this work, groove-textured surfaces with a certain widths and pitches are manufactured on flat cast iron samples. Whereafter, another material (aluminium and steel, respectively) is filled into the grooves to form a special surface which possesses space-varying properties. These surface-treated specimens are tested in a ball-on-flat system and the ensuring friction-induced vibration and noise are measured. The ball sample used in the test is chromium bearing steel ball (AISI 52100). It is found that adding aluminium material into the grooves will increase the friction-induced vibration and noise level of friction system. Conversely, adding steel material into the grooves can stabilize the friction system. Moreover, this space-varying contact state surface is valuable to study the relationship between the trapping wear debris behaviour and stability of texturing surface, which validates our previous speculation that wear debris accumulation on the contact surface will deteriorate the friction-induced vibration and noise behaviour of friction system, and the capability of grooves in trapping wear debris is beneficial for reduction of vibration and noise. Numerical simulation is performed to give reasonable explanations for the experimental phenomenon. This investigation suggests that friction surfaces with grooves filled with suitable materials are able to reduce friction-induced vibration and noise.

Experimental Analysis of Grease Friction Properties on Sliding Textured Surfaces

There is comprehensive work on the tribological properties and lubrication mechanisms of oil lubricant used on textured surfaces, however the use of grease lubrication on textured surfaces is rather new. This research article presents an experimental study of the frictional behaviours of grease lubricated sliding contact under mixed lubrication conditions. The influences of surface texture parameters on the frictional properties were investigated using a disc-on-ring tribometer. The results showed that the friction coefficient is largely dependent on texture parameters, with higher and lower texture density resulting in a higher friction coefficient at a fixed texture depth. The sample with texture density of 15% and texture depth of 19 μm exhibited the best friction properties in all experimental conditions because it can store more grease and trap wear debris. The reduction of friction is mainly attributable to the formation of a stable grease lubrication film composed of oil film, transfer film and deposited film, and the hydrodynamic pressure effect of the surface texture, which increases the mating gap and reduces the probability of asperity contact. This result will help in understanding the tribological behaviour of grease on a textured surface and in predicting the lubrication conditions of sliding bearings for better operation in any machinery.

Comparisons of tribological properties between laser and drilled dimple textured surfaces of medium carbon steel

PurposeThe study aims to compare tribological properties between laser dimple textured surface and drilled dimple textured surface, and to analyze the influence of dimple hardened edges and ability of trapping wear debris on wear properties of dimple textured surfaces.Design/methodology/approachCircular textured dimples were produced on AISI 1,045 specimen surfaces using laser surface texturing (LST) and drilled surface texturing (DST) methods. Tribological behaviors of LST, DST and non-textured specimens were studied using ball-on-disc tribo-tester. Metallographic structures, dimples and worn surface morphologies were observed using a three-dimensional digital microscope. Hardnesses of substrate and dimple edges were measured.FindingsThere was no obvious difference in wear and friction coefficients between LST and DST specimens. Hardnesses of laser dimple edges were much higher than that of drilled dimple edges and specimen substrate. The hardened materials of laser dimple edge included recast zone and heat affect zone. Laser dimple was cone-shaped and drilled dimple was cylinder-shaped. Drilled dimple had a better ability of trapping wear debris than laser dimple. Non-uniform wear phenomenon occurred on worn surfaces of LST dimple specimens.Originality/valueThe ability of textured dimples to trap wear debris is affected by single dimple volume. Hardened edges of dimples cause non-uniform wear on worn surfaces of LST specimens.

The Effect of Textured Surfaces with Different Roughness Structures on the Tribological Properties of Al Alloy

In this study, four kinds of roughness structures were constructed on the Al alloy surface using laser marking technology. The tribological properties of the surfaces under the condition of dry friction were carefully investigated. The results indicate that the fabricated surfaces have similar compositions. The hardness of surfaces can be improved after the laser surface treatment. Besides, the texturing of surfaces can efficiently reduce friction and improve friction resistance. However, the friction-reducing mechanisms are not the same. The surfaces with lined and grating grooves can remove wear debris away from the interfaces between steel balls and surfaces, while those with irregular protrusions and micro-orifices array would be able to trap wear debris in the microstructure. Furthermore, due to the different friction mechanisms of distinct roughness structures, their friction-reducing performances are greatly affected by the actual friction conditions (sliding speed and load), which offers a guide for constructing a specific roughness structure on the Al alloy surface to improve its friction resistance efficiently.