Effect of laser surface texturing on friction behaviour in elastohydrodynamically lubricated point contacts under different sliding-rolling conditions

Boidi, G.; Tertuliano, I.S.; Profito, Francisco J.; Rossi, Wagner de; Machado, Izabel Fernanda

doi:10.1016/j.triboint.2019.02.021

Cited by 50 publications

(35 citation statements)

References 26 publications

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“…3 The essential information for understanding the research was reported here, and complementarily the main results obtained has been already published elsewhere [18][19][20][21][22][23].…”

Section: Research Questionsmentioning

confidence: 61%

“…Main effects of surface micro cavities (pores and texture) were summarized in As previously summarized in Table 6.1, small porosity (SP) material performed friction reduction within the range of speeds studied, approximately around 10% (see Another crucial factor to be considered in concentrated contact test is the feature depth [18,95]. The counter-body passage on a textured surface could cause the increase of local pressure and viscosity.…”

Section: Modelmentioning

confidence: 99%

“…Relação deslizamento-rolamento. Table 3.3 -Geometrical characteristics and laser parameters used for disk texturing (Ti-Sapphire laser), adapted from [18] Table 3.5 -Summary of surface micro features topographical characteristics. ......... 28 Table 4.1 -Geometrical characteristics and main effects of most common texture configurations.…”

Section: Introductionmentioning

confidence: 99%

“…Schematic representation of texturing configurations manufactured on smooth disks, top view of disks. Ue represents the entrainment speed, adapted from[18].…”

mentioning

confidence: 99%

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An experimental assessment of surface micro irregularities (porosity and texture) effects on tribological behaviour under lubricated conditions.

Boidi¹

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recent years, although this procedure usually implies extra manufacturing operations and costs. On the other hand, sintered materials contain themselves surface cavities that could potentially act as surface texture and, consequently, lead to friction reduction. This research aims to extend the current knowledge on the tribological influence of micro surface irregularities (pores and laser texture) under lubricated experimental tests and explore the use of these features for tribological applications. Samples were manufactured using both sintering and texturing processes to obtain different surface characteristics. Three different porosity conditions were produced for sintered steels, whereas grooves and dimples configurations were designed for textured steel samples. After that, experimental tests were performed under varying sliding-rolling conditions (from prevalent rolling to prevalent sliding) especially using non-conformal contact. Speed was also varied during frictional tests to cover a wide range of operational conditions and verify the effects of surface features under different lubrication regimes. Friction tests were carried out with two tribometers using configurations of pin-on-disk, roller-on-disk and ball-on-disk. Film thickness was measured by an ultra-thin optical interferometry rig using a methodology properly designed for rough samples. Samples with smooth surfaces were utilized as a reference bench to be compared to material with surface modification (texture or porosity). Main results showed that the decrease of porosity led to friction reduction in the sintered steel. Material with reduced porosity performed even better than reference smooth samples. In addition, the dimple configuration promoted friction reduction, whereas grooves generally performed similarly or worse than reference material. Even if textured dimples and small porosity on sintered material were produced by different techniques, they presented similar geometrical characteristics and consequently they both reduced friction compared to reference samples. As part of the outcome, main results were mapped to better understand the effect of each surface feature on tribological performance. Furthermore, a preliminary phenomenological model was proposed to predict frictional response of surface with micro cavities (pores or texture) from reference steel results. Main findings suggest that the effect of tailored surface cavities could be somehow compared to randomly distributed ones, even if produced by very different manufacturing techniques.

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“…3 The essential information for understanding the research was reported here, and complementarily the main results obtained has been already published elsewhere [18][19][20][21][22][23].…”

Section: Research Questionsmentioning

confidence: 61%

Section: Modelmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…Schematic representation of texturing configurations manufactured on smooth disks, top view of disks. Ue represents the entrainment speed, adapted from[18].…”

mentioning

confidence: 99%

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An experimental assessment of surface micro irregularities (porosity and texture) effects on tribological behaviour under lubricated conditions.

Boidi¹

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“…Other than ion implantation, shot peening, and surface coating methods, surface texturing and patterning methods have been widely studied recently, which has obvious effects on improving the surface friction performance of tools [4]. Studies have shown that, when the surface of tools has a certain texture, its wear resistance will be improved, and a certain non-smooth surface will improve the friction and lubrication properties of the lubricating fluid [5,6].…”

Section: Introductionmentioning

confidence: 99%

Study on Friction and Lubrication Characteristics of Surface with Unidirectional Convergence Texture

Yang

Wang

et al. 2019

Coatings

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In order to study the influence of texture on the wear and lubrication performance of the surface of the tools, three kinds of textures with unidirectional convergence morphology were processed on the surface of the samples, and each texture was designed with different area occupancy ratios. Simulation analysis shows that, owing to the reflow and convection effect of liquid in the texture, the lubricating film flowing through the textured surface has a high hydrodynamic pressure value, and the semicircular ring texture is the most prominent. By comparing the friction coefficient, when the area occupancy ratio of texture on the surface is 10%, the surface of the samples with different morphology has the lowest coefficient of friction; the friction coefficient of the semicircular ring textured surface is especially very low. Surface textures reduce the direct contact area between the friction pairs, and generate dynamic pressure lubrication and secondary lubrication, so that the surface friction coefficient of the samples is obviously reduced. The surfaces of the non-textured samples have abrasive wear and contact fatigue wear, and the surfaces of the textured samples have adhesive wear, abrasive wear, and cavitation.Coatings 2019, 9, 780 2 of 21 chemical properties of the surface can be improved by changing the surface morphology, such as surface texture. In 1966, Hamilton [8] proposed the additional fluid dynamic pressure effect; that is, when the liquid flows through the pits or grooves machined on the surface of the friction pair, a small convergence wedge and a divergent wedge are formed. When the friction pair is in relative motion, the fluid in the convergence wedge generates a dynamic pressure effect, thereby forming a positive pressure; while in the divergent wedge, owing to the existence of the "cavitation" phenomenon, the "negative pressure" of the fluid is restrained. Therefore, additional hydrodynamic pressure is formed between the friction pairs, which improves the bearing capacity of the fluid.Liu et al.[9] used a picosecond laser to achieve micro-texture on the surface of cast iron, and investigated the friction and wear properties of four different surfaces of smooth, pit textures, net textures, and intermittent textures. The study found that under the dry friction condition, the surface machined micro-texture can significantly improve the stability of the friction coefficient compared with a smooth surface, but different textures have different effects on the stability and initial value of the friction coefficient.Gachot et al.[10] fabricated regular pits on the silicon surface by photolithography and wet etching, and tested the friction under boundary lubrication. The results show that the high-density pit morphology has a low coefficient of friction, and when the sliding direction and pit row of the cloth is at a 30 degree angle, the friction is reduced. Zeeshan Ur Rehman [11], Faiz Muhaffel [12], and Aliofkhazraei [13] have also done a lot of research in the field of coatings and textures. E...

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Femtosecond laser texturing of DLC-based coatings by DLW method with sub-micrometer precision

Čermák

Simonovic

Бондарев

et al. 2022

Int J Adv Manuf Technol

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The enhancement of functional surfaces by laser texturing has been investigated in many studies; however, it has been often applied to the substrate. New laser technologies, such as the direct laser writing (DLW) method using a femtosecond laser, allow the production of extremely precise textures into both substrates and thin lms. This paper investigates two distinct methods producing various textures:(i) the substrate is textured before the deposition of the diamond-like carbon coating (DLC), and (ii) the texture is produced into DLC coating deposited on a polished substrate. Our goal was to achieve identical topography in both cases; the textured area was as large as 170 mm 2 . The textured topography was assessed by 3D laser scanning microscope, which con rmed the repeatability of fs laser processing. Raman spectroscopy mapping, SEM, and XPS were combined to investigate the effect of laser processing on DLC coating in terms of oxidation or structural changes. 1. Introduction Many industrial areas face various pressure such as cost-effectiveness, environmental aspects, substitutability of different technologies and its consequent exibility of change. Surface treatments, namely surface texturing by ultra-short pulsed (USP) lasers has been already used in many industrial elds: in the cutting tool industry [1] to improve the cutting process, in piston rings [2], dies preparations for metal forming [3], in bearings [4] for friction reduction; and in other elds such as biomedical equipment [5] or storage devices [6]. Many scienti c papers [7]-[13] dealt with laser surface texturing of DLC coatings, which consisted of dimple shapes limited by applied laser spots from d = 10µm [12] up to 30µm [8] in rectangular/square patterns. The performed experiments showed the coe cient of friction (CoF) reduction when using ultrashort pulsed laser processing [8], [11],[13], instead of short-pulsed laser processing [14], where the heataffected zone (HAZ) seems to be limiting improvement in tribological properties. Other studies [15]-[17] aimed to fabricate different textures, e.g., squares, lines, or circles in many possible patterns.These studies were mainly focused on the impact of various densities of geometrical entities, but not on the achieved depth of textures, which did not allow a proper insertion of laser texturing into various places of the technological production chain. In the study of Dumitru et al. [10], laser texturing was performed in two variants: into the substrate before deposition of DLC coating and after the deposition.However, the depths of the texture were not provided.This study focuses on the fabrication of textures with de ned geometrical entities and conditions by ultra-short pulsed (USP) laser system tuned to a pulsed length of 240fs. Our main goal is to compare the feasibility of two texturing processes. In the rst case, designed textures were micromachined directly into the substrate (tool steel 1.2379) and then the samples were deposited by DLC coating (hereinafter textured-coated). In the second...

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Effect of laser surface texturing on friction behaviour in elastohydrodynamically lubricated point contacts under different sliding-rolling conditions

Cited by 50 publications

References 26 publications

An experimental assessment of surface micro irregularities (porosity and texture) effects on tribological behaviour under lubricated conditions.

An experimental assessment of surface micro irregularities (porosity and texture) effects on tribological behaviour under lubricated conditions.

Study on Friction and Lubrication Characteristics of Surface with Unidirectional Convergence Texture

Femtosecond laser texturing of DLC-based coatings by DLW method with sub-micrometer precision

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