Surface Tribological Properties Research Articles

Tribological Properties of Surface Alloyed AISI 1045 Steel with Titanium in a Nitrogen Containing Atmosphere

Tribological Properties of Surface Alloyed AISI 1045 Steel with Titanium in a Nitrogen Containing Atmosphere

Morphological and functional characterization of electroplated Ni-graphene composite coatings

Composite coatings (CECs) are providing a unique technological advantage for improving mechanical and tribological surface properties. Among different methods, electrodeposition is one of the most exploited to produce composite surface coatings on metal substrates. However, the process parameters affect graphene distribution, coating morphology and performance. This paper investigates how different deposition conditions influence the inclusion of large Graphene nanoplates (GnPs) in a Nickel matrix and the coating morphology and tribological performance. Set the process condition such as electrical parameters and the galvanic bath, the work focuses on the stirring rate effect. To this end, Ni-GnP coatings were obtained by a laboratory setup and evaluated through surface profilometry, SEM characterization and a dry-sliding linear reciprocating wear test. The results highlight the influence of stirring on coating uniformity. The low stirring rate allows larger particles to be embedded, which are not thoroughly covered; however, they act as a solid lubricant and reduce the friction coefficient.

Electrofluid in-situ forming MoS2-TiO2 lubricant-hard alternate coatings sintered at different temperatures

The study in-situ forms MoS2-TiO2 lubricant-hard alternate coatings with varying TiO2 sintering temperatures (400 °C/500 °C/600 °C/700 °C) on TC4 titanium alloy surfaces using the electrohydrodynamic atomization (EHDA) technique, and assesses the impact of sintering temperatures on reciprocating sliding wear of coating. The surface and interface microstructures, the interfacial bonding performance, and surface tribological properties of alternate coatings were compared with single material coatings. Results showed that MoS2-TiO2 alternate coating with TiO2 hard phase sintered at 600 °Ϲ exhibited the most effective lubrication, with a friction coefficient of ∼0.07, which reduced 42 % compared to the pure MoS2 coating. Its reciprocation wear life was 21 % shorter and the coating wear rate decreased 43.3 %. Additionally, the study analyzed the mechanism of the influence of sintering temperature on the lubrication of the alternate coatings and confirmed that the alternate TiO2 and MoS2 can effectively enhance the tribological properties compared to single material coating.

Effect of picosecond laser surface texturing under Babbitt coating mask on friction and wear properties of GCr15 bearing steel surface

The recast layer is usually formed during laser texturing of GCr15 bearing steel. The recoil pressure (caused by material vaporization) and Marangoni heat flow cause the molten material to splash out and accumulate at the texture edge to form the recast layer. The adverse thermal effects of laser texturing can cause hot cracks, non-uniform hardening zones, and MC carbide growth. These phenomena are generally unfavorable to the tribological properties of surfaces. This study proposes an effective solid mask laser ablation (SMLA) method for reducing the adverse thermal effects caused by laser texturing (such as recasting layer and splashing molten material). The results show that the shape of micro-dimples treated by SMLA was more regular. The accumulation of the recast layer and heat affected zone (HAZ) was also significantly reduced. The multi-layer samples textured by the SMLA method have better properties of storing oil and capturing the wear debris. The soft mask can also act as a solid lubricant. The coefficient of friction (COF) and specific wear rate of samples were significantly reduced.

Regulation Mechanism of Special Functional Groups Contained in Polymer Molecular Chains on the Tribological Properties of Modified Ti6Al4V.

Polymer coatings can effectively improve the surface tribological properties of human implant materials, thereby increasing their service life. In this study, poly(vinylsulfonic acid, sodium salt) (PVS), poly(acrylic acid) (PAA) and poly(vinylphosphonic acid) (PVPA) were used to modify Ti6Al4V surfaces. Experimental analyses were combined with molecular simulation to explore the regulation mechanism of special functional groups contained in polymer molecular chains on the tribological properties of modified surfaces. In addition, the bearing capacities and velocity dependence of different polymer modified surfaces during friction were also explored. The PVS coating, due to physical adsorption, can have an anti-friction effect under NaCl solution lubrication, but is not durable under long-term or repeated usage. Both PAA and PVPA molecular chains can form chemical bonds with Ti6Al4V. Phosphate acid groups can firmly bind to the substrate, and the adsorption of salt ions and water molecules can form a hydrated layer on the PVPA coating surface, achieving ultra-low friction and wear. The adsorption of salt ions would aggravate the surface wear of the PAA-modified Ti6Al4V due to the unfirm binding of carboxyl groups to the substrate, resulting in a high friction coefficient. This study can provide effective guidance for the design of modified polymer coatings on metals.

Influence of hardness of nanoparticle additive in PTFE solid lubricant on tribological properties of GCr15 steel with bionic texture

The surface microstructure of biomimetic Procambarus clarkia claw was prepared on the surface of GCr15 steel, then PTFE solid lubricants dispersed with three different hardness nanoparticles (C, ZnO, Al2O3) were filled in. The results of the tribological experiment show the textured surface lubricated by PTFE with Al2O3 nanoparticles reflected the best performances. Because PTFE stored by the bionic texture could be supplied to the friction surface to form a solid lubrication film. Due to the addition of Al2O3 nanoparticles, the hardness and wear resistance of the film are improved, thus avoiding a large loss of PTFE. And the process of "rolling-embedding PTFE surface-exposing-rolling" occurs. As a final, the surface tribological properties of GCr15 steel can be significantly improved.

Effect of acid erosion on the tribological performance of surface texture prepared with laser processing

PurposeThe purpose of this study is to further improve the performance of surface texture, the chemical polishing method was introduced and the effect of it on the surface morphology and tribological properties of the surface texture was investigated.Design/methodology/approachThe surface texture was processed on the surface of 304 stainless steel with laser technology in air medium. Hydrochloric acid solution (pH 2.4 ± 0.05) was selected and used to soak the prepared texture samples for 12 h. The surface morphology and elemental content of the samples were measured with the white light interferometry, SEM and EDS. To obtain the effect of acid corrosion on the tribological properties of textured surfaces, the samples were tested under dry friction and oil lubrication conditions.FindingsThe detailed study shows that the melt and burr of surface texture produced with laser processing was reduced due to the corrosion effect of hydrochloric acid. Therefore, the better interfacial tribological properties was obtained due to the improvement of surface-textured morphology.Originality/valueThe main contribution of this work is to provide a new reference for improving surface texture quality. It also lays a foundation for improving the tribological properties of the textured interface.Peer reviewThe peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-04-2023-0094/

Surface tribological and electrochemical properties of TiAlSiN coating in seawater

To investigate the effects of friction surface and electrochemical properties on the tribological behavior of TiAlSiN coatings in seawater, the tribological properties of TiAlSiN coatings in air and seawater are comparatively studied using a ball-on-disk tribometer with Si3N4 ceramic balls as the counter material. The results show that under both friction conditions, the wear rate of TiAlSiN coating is decreased compared with 316 l steel substrate, and the coating presents a good protective effect. When friction occurs in air, the abrasive debris in the wear area cannot be discharged in time, resulting in the accumulation of abrasive debris and accelerating the wear of the coating. When friction occurs in seawater, although seawater is corrosive, the lubricating barrier surface formed by the friction oxide during the friction process significantly reduces the wear rate of the coating. In addition, the excellent electrochemical properties and the dense coating microstructure improve the tribocorrosion resistance of the TiAlSiN coating in seawater. It proves that friction surface has a great impact on the tribological performance of TiAlSiN coatings, and how to form a more favorable friction layer in the tribochemical environment is worthy of further research in the field of marine equipment.

Effect of Salt Bath Nitriding and Reoxidation Composite Texture on Frictional Properties of Valve Steel 4Cr10Si2Mo

In order to improve the service life of 4Cr10Si2Mo valve steel, laser processing technology was used to prepare triangular textures with different area occupancies on the surface of 4Cr10Si2Mo, and then 4Cr10Si2Mo was subjected to salt bath nitridation (salt bath temperature 580 °C) and oxidation (oxidation temperature 400 °C). The mechanism of composite surface treatment technology on friction and wear performance of valve steel was explored. The effect of triangular texture on working surface stress and hydrodynamic pressure was explored using simulation technology, and the mechanism of texture in friction was further studied. The XRD test results showed that after salt bath nitriding and reoxidation treatment, the surface of 4Cr10Si2Mo mainly contained Fe2N oxide film and Fe3O4 and other components. The XPS test showed that the nitriding layer contained Cr-N, and the surface hardness reached 710.5 HV0.5. The simulation results showed that introducing surface texture will increase the stress on the contact surface, especially near the texture. However, under lubricating conditions, the flow field in the textured lumen produces a wedge effect, which increases the oil film pressure. After salt bath nitriding composite texture treatment, the wear resistance of 4Cr10Si2Mo significantly improved under the synergistic effect of the nitrided layer dominated by the magnetite phase (Fe3O4) and the microtexture. Fe3O4 can reduce the friction coefficient and resist oxidation reactions. In addition, the texture of the area occupancy of the texture also affects the surface tribological properties. The texture with an area occupancy rate of 11.45% (low × high is 0.3 mm × 0.3 mm) had the best anti-friction effect, and the friction coefficient reduced by 65%.

The Effect of Various Contaminants on the Surface Tribological Properties of Rail and Wheel Materials: An Experimental Approach

This study reports on the tribological behavior of Indian rail track and wheel materials under different contaminants. A pin-on-disc tribometer was selected for the experimental analysis in ambient conditions (temperature of 24.9 °C and relative humidity of 66%). Sand, mist, leaves, and grease were the contaminants used in this investigation. The railway track was used to make the pin, and the wheel was used to make the disc. The acquired results were analyzed using frictional force and wear depth as a function of time as the variables. These pollutant effects were compared to no-contaminant conditions. It was observed that the sand increased the friction force and wear depth, whereas oil decreased friction and wear. Mist and leaves also reduced friction and wear. The effect of leaves was higher than the mist. The effect of load on various contaminants was also investigated. The results showed that as the load increased, the friction force and wear also increased for all contaminants. The results of this study can help in understanding the wear phenomenon of wheels and rail tracks in different parts of India.

Study on the Influence of Surface Texture Parameters of Oil Production Screw Motor Rotor on the Tribological Properties of Its Friction Pair

By researching the influence of micro-groove texture on the surface tribological properties of the stator and rotor pair of oil production hydraulic motors, this paper aims to reduce the frictional resistance moment of the spiral pair of hydraulic motors, and further solve the problem of the difficult restart of the pump of a certain type of hydraulic-driven screw pump. According to the spiral pair of screw motors, a metal-rubber flat plate reciprocating friction model is established, and rectangular micro-grooves with different texture angles and depths are machined on the surface of the metal specimen. A combination of finite element simulation and tribological tests is used to carry out a study on the influence of different texture parameters on the friction performance of the hydraulic motor spiral pair. The results showed that at a certain texture angle, the friction coefficient of each specimen basically increases with the texture depth. When the texture depth is constant, the friction coefficient increases first and then decreases with the increase of the texture angle. The texture angle is the main factor affecting the friction coefficient. Under the same test conditions, the friction coefficient of the textured specimen can be reduced by 20.2% compared with the untextured specimen. In the metal-rubber contact pair of the stator and rotor of the hydraulic motor, the friction reduction mechanism of the texture mainly transport the lubricating medium through the micro-grooves to improve the lubricating conditions. Samples with a reasonable design of texture parameters can effectively reduce the friction coefficient of the friction pair without reducing the service life of the hydraulic motor, which is conducive to the smooth restart of the oil production system of the hydraulically driven screw pump.

Tribological response of groove-textured surface with compressive stress on Ti6Al4V processed by laser and abrasive belt

Both texturing and residual stress have a positive effect on tribological properties of surface. According to the effect, a synergistic processing method by laser and abrasive belt is proposed. The results show that the texture of co-processed surface is more regular and flatter with stronger grooves retention. With none stress and initial stress as the benchmark, the co-processed surfaces are all in compressive stress. The co-processed surfaces exhibit some advantages under dry friction and boundary lubrication. When residual compressive stress is greater than the initial, the surfaces show better wear resistance where wear depth can be reduced by 56.88 % from 2.69 mm to 1.16 mm and wear area width can be reduced by 44.90 % from 689.41 mm to 379.84 mm.

The Use of Electrochemical Methods to Determine the Effect of Nitrides of Alloying Elements on the Electrochemical Properties of Titanium β-Alloys.

Titanium beta alloys represent the new generation of materials for the manufacturing of joint implants. Their Young's modulus is lower and thus closer to the bone tissue compared to commonly used alloys. The surface tribological properties of these materials should be improved by ion implantation. The influence of this surface treatment on corrosion behaviour is unknown. The surface of Ti-36Nb-6Ta, Ti-36Nb-4Zr, and Ti-39Nb titanium β-alloys was modified using nitrogen ion implantation. X-ray photoelectron spectroscopy was used for surface analysis, which showed the presence of titanium, niobium, and tantalum nitrides in the treated samples and the elimination of less stable oxides. Electrochemical methods, electrochemical impedance spectra, polarisation resistance, and Mott-Schottky plot were measured in a physiological saline solution. The results of the measurements showed that ion implantation does not have a significant negative effect on the corrosion behaviour of the material. The best results of the alloys investigated were achieved by the Ti-36Nb-6Ta alloy. The combination of niobium and tantalum nitrides had a positive effect on the corrosion resistance of this alloy. After surface treatment, the polarization resistance of this alloy increased, 2.3 × 106 Ω·cm2, demonstrating higher corrosion resistance of the alloy. These results were also supported by the results of electrochemical impedance spectroscopy.

Synergistic effect of surface sinusoidal textures and oxide layer on tribological properties of 40Cr alloy steel

Researchers have been concentrating on enhancing the surface tribological properties and minimizing wear on mechanical components during the oil starvation stage. In this work, a nanosecond laser was used to prepare sinusoidal textures of different amplitudes on the surface of 40Cr alloy steel, and then the obtained surfaces were pre-oxidized at 100 °C, 300 °C, and 500 °C, respectively. The results demonstrated that excessively large or small amplitude values would reduce the wear debris trapping ability of the textures, which ultimately affected the formation of the tribofilm. In addition, the numerical simulation results reveal that the texture pressure difference is positively correlated with the texture amplitude, but excessively high or low amplitude leads to a significant micro-vortex effect within the texture. The tribological properties of the textured surfaces could be further enhanced by the pre-oxidation treatment. The experiment results indicated that the pre-oxidation treatment increased the degree of surface oxidation and promoted the formation of tribofilm. This work will pave the way to improve surface tribological properties by integrating sinusoidal textures and self-generated tribofilm.

A Review of Effects of Femtosecond Laser Parameters on Metal Surface Properties

As a laser technology, the femtosecond laser is used in biomedical fields due to its excellent performance—its ultrashort pulses, high instantaneous power, and high precision. As a surface treatment process, the femtosecond laser can prepare different shapes on metal surfaces to enhance the material’s properties, such as its wear resistance, wetting, biocompatibility, etc. Laser-induced periodic surface structures (LIPSSs) are a common phenomenon that can be observed on almost any material after irradiation by a linearly polarized laser. In this paper, the current research state of LIPSSs in the field of biomedicine is reviewed. The influence of laser parameters (such as laser energy, pulse number, polarization state, and pulse duration) on the generation of LIPSSs is discussed. In this paper, the applications of LIPSSs by femtosecond laser modification for various purposes, such as in functional surfaces, the control of surface wettability, the surface colonization of cells, and the improvement of tribological properties of surfaces, are reviewed.

Study on Tribological Characteristics of Textured Surface under Convergent Oil Film Gap

Under the condition of convergence, a textured non-parallel 2D slider bearing model was established, and the tribological properties of textured surface under the convergence gap were numerically studied with the load-carrying capacity as an indicator. Firstly, whether the convergence ratio parameter can accurately characterize the joint effects of film thickness difference and oil film thickness on the surface tribological properties was verified, and the effects of film thickness difference and oil film thickness on the load-carrying capacity of textured and non-textured surface were studied, respectively. The results show that the efficiency of improving the load-carrying capacity of the surface structure first increases and then decreases with the increase of the oil film thickness. In the case of large film thickness difference, the surface texture will reduce the efficiency of improving the load-carrying capacity. In addition, the effects of texture depth, texture width, and sliding velocity on the load-carrying capacity under the convergence gap are also studied. In particular, an optimal texture width to maximize the load-carrying capacity exists.

Study on antifriction mechanism of surface textured elliptical bearings

Abstract The surface micro texture can improve the surface tribological properties of friction pairs. As a two oil wedge bearing, elliptical bearing can restrain the journal whirl and maintain the stable operation. In the manuscript, the surface micro-texture is combined with elliptical bearing, and the influence of micro-texture shape, micro-texture depth and micro-texture radius on oil film pressure, bearing capacity and friction coefficient of elliptical bearing is studied by theoretical calculation and experimental research. The results show that with the increase of micro-texture depth, the bearing capacity first increases and then decreases; and when the dimensionless texture depth is 0.03, the bearing friction is the lowest and the bearing capacity is the highest. When the dimensionless radius of the micro texture is v3, the lubrication performance of the bearing is the best. When the shape of micro-texture is circle or triangular, the lubrication performance of elliptical bearing can be improved.

Atomistic understanding toward the improved scratching properties of GaAs coated with monolayer graphene

Molecular dynamics simulation was performed to study the surface nanotribological behavior and subsurface damage of gallium arsenide (GaAs) substrate coated with monolayer graphene when subjected to the scratching action of diamond abrasive. Simulation result shows that the coefficient of friction and wear volume of GaAs/graphene surface are evidently lower than those of the bare GaAs surface for various scratching depths. The material removal of the graphene-coated GaAs workpiece is primarily attributed to compression- and shear-induced plastic deformation of GaAs, whereas abrasive wear is the dominant material-removal mechanism for bare GaAs workpiece. On the contrary, the GaAs workpiece coated with graphene exhibits severe subsurface damage due to the higher stress and that graphene can suppress the stress released within the GaAs workpiece during scratching; hence, the stress has to spread deeply. The scratching-induced slight deformation of graphene occurs when the scratching depth is higher than 15 Å. The deformed graphene induced by scratching is still capable of protecting GaAs substrate to some extent, but its C-C bond is vulnerable to be ruptured at the end of the scratching path due to a scratching-induced bulge structure. Increasing temperature can promote the scratching-induced surface wear and subsurface damage of GaAs workpiece. Monolayer graphene can improve the surface tribological properties of GaAs at each temperature. This work can provide atomic insights into the antifriction and antiwear design for GaAs when graphene is used as a coating.

Properties of Multifilament PGA Suture Coated with Graphene Oxide

With the development of fine surgery and desire for low-injury methods, the frictional properties of surgical sutures are one of the crucial factors that can cause damage to tissue, especially for some fragile and sensitive human tissues such as the eyeball. In this study, dopamine hydrochloride and graphene oxide were used as external application agents to prepare a biological coating for the surface of multifilament surgical sutures. The effects of this biocoating on the surface morphology, chemical properties, mechanical properties, and tribological properties of surgical sutures were studied. The friction force and the coefficient of friction of surgical sutures penetrating through a skin substitute were evaluated using a penetration friction apparatus and a linear elastic model. The tribological mechanism of the coating on the multifilament surgical sutures was investigated according to the results of the tribological test. The results showed that there were uniform dopamine and graphene oxide films on the surface of the surgical sutures, and that the fracture strength and yield stress of the coated sutures both increased. The surface wettability of the surgical sutures was improved after the coating treatment. The friction force and the coe_cient of friction of the multifilament surgical sutures with the dopamine hydrochloride and graphene oxide coating changed little compared to those of the untreated multifilament surgical sutures.

Tribological Performance of Multiscale Micro-Textured H62 Brass Surface Fabricated by Micro-Milling and Wet Micro-Blasting

Abstract The cylinder block/valve plate interface in the axial piston pump has been proven to be easily worn out, which will increase power loss and reduce its efficiency. The valve plate surface is required to be manufactured with low viscous friction and wear. Multiscale micro-texture has been proven to improve surface tribological properties. However, there are few types of research in the effect of surface topography on the tribological performance of multiscale micro-textured surfaces. The purpose of this study is to explore how the multiscale micro-texture on H62 brass affects its sliding friction behavior on 38CrMoAl. Based on micro-milling and wet micro-blasting, the multiscale micro-textured surface was manufactured on H62 brass. The wet micro-blasting was applied in the H62 brass after the surface micro-texturing. The surface topography of multiscale micro-textured samples processed by three abrasive grit sizes accompanied by two processing times was comprehensively measured in terms of height, feature, functional, and functional volume parameters. The tribological performance of multiscale micro-textured H62 brass was characterized by disk-on-disk frictional experiments. Through analyzing the relationship between surface morphology and tribological properties, the antifriction mechanism of the multiscale micro-textured surface was analyzed from the perspective of 3D surface roughness parameters. The friction coefficient of the multiscale micro-textured surface processed by the combination of micro-milling and wet micro-blasting decreased with the increasing grit size and micro-blasting time.