The constant development of environmental protection causes the necessity to increase the efficiency of machines. By increasing the efficiency of machines, energy losses can be limited, leading to ...lower energy consumption. Friction reduction leads to an increase in efficiency and a decrease in wear. In this paper, selected surface texturing methods, such as burnishing and abrasive jet machining, with their limitations are presented. Thanks to those processes, various surface textures can be obtained. Examples of applications of these methods for friction and wear reduction are shown.
Laser surface texturing (LST) is a method to obtain micro-structures on the material’s surface for improving tribological performances, wetting tuning, surface treatment, and increasing adhesion. The ...material selected for LST is AISI 430 ferritic stainless steel, distinguished by the low cost in manufacturing, corrosion resistance, and high strength at elevated temperature. The present study addresses the morphology of new pattern designs (crater array, ellipse, and octagonal shapes). The patterns are applied on the stainless-steel surface by a non-contact method with high quality and precision nanosecond pulsed laser equipment. The investigation of laser parameter influence on thermal affected area and micro-structures is accomplished by morphological and elemental analysis (SEM + EDX). The parameters of the laser micro-patterning have a marked influence on the morphology, creating groove-type sections with different depths and recast material features. From the SEM characterization, the highest level of recast material is observed for concentric octagon LST design. Its application is more recommended for the preparation of the metal surface before hybrid welding. Additionally, the lack of the oxygen element in the case of this design suggests the possible use of the pattern in hybrid joining.
Materials with well-defined surface structures are prepared using protective coatings through surface texturing, which is a novel method for modifying surface characteristics, particularly ...tribological and wettability, to improve the properties of material parts. The formation of a specific patterned surface can be achieved through abrasive blasting, reactive-ion etching, lithography and mechanical machining. This review focuses on laser technology because it generates the most controllable and precise geometries. This technique is environmentally friendly because it does not utilise any chemical reagent, nor does it produce significant waste.
In this study, a picosecond (ps) laser was employed to produce micro-textures on ductile iron in linearly processing leading to significantly higher processing efficiency. The fabrication efficiency ...was increased about 1331 times as compared to the more common spot-by-spot texturing method. The ps laser induced graphene (LIG) structures were simultaneously fabricated in dimples, which further enhanced the surface tribological properties. The surface micro-textures were produced by forming micro-dimples on the substrate via the laser ablation process. The dimple diameter and area density were regulated by varying the key laser processing parameters, and were experimentally correlated to the tribological properties of the ductile iron substrate. To understand deeper into the wear reduction mechanism of the micro-dimples, simulation models based on the Reynold equation were established, which analyze the flow field pressure distribution and demonstrate the hydrodynamic lubrication effect of the micro-textures. The ball-on disk friction test showed that the area density of the micro-textures had a significant influence on the friction and wear properties. The micro-texture with the area density of 20% and the average dimple diameter of 36 μm showed the highest volume wear rate reduction of 70% and the friction coefficient reduction of 20% respectively. The results indicated that the simultaneous laser in-situ generation of graphene micro-textures is an effective way of enhancing tribological properties on the ductile iron surface. It enhances the hardness of textured surfaces, thermal diffusion, debris capture ability, and fluid dynamic lubrication effect.
Water lubrication is one of the candidates of the tribo-system with low negative environmental impact. It is well known that some kinds of ceramics show excellent tribological properties under ...lubrication with water. The characteristic improvement was attempted by giving texturing to Si3N4 so that the water lubrication might spread as a representative of the ecotribology system. The surface laser texturing showed the friction reducing effect under the sliding condition of the low bearing characteristic number. The mechanism of the triblogical property improvement by the laser surface texturing was discussed based on the experiment results and the surface analytical results.
► Laser surface texturing leads the excellent water lubrication properties of Si3N4. It is considered that the texturing dimple pattern affects to form and keep the smooth sliding surface with the tribo-chamical reaction products. ► Improving effect of surface texturing depends on the dimple pattern. It is important to optimize the texturing pattern. ► The dimples have an important function to trap the wear debris, which causes the abrasive damages on the sliding surface.
•Effects of groove spacing on wear resistance of non-smooth surface are studied.•Effects of LSP on the wear resistance of non-smooth surface are investigated.•Influence process of LSP on wear ...resistance of non-smooth surface is analyzed.
The friction coefficient and wear resistance of non-smooth surface with different conditions are studied in this work. First, the effects of groove spacing on the friction behavior and wear resistance of the non-smooth surface are investigated. Second, the effects of massive laser shock peening (LSP) impact on the dry sliding wear performance of the non-smooth surface manufactured by laser surface texture (LST) are evaluated. In addition, the worn surfaces and typical microstructure in the top surface layer of all samples were characterized by field emission scanning electron microscope (SEM) with an EDS elemental analysis and transmission electron microscopy (TEM). The influence process of groove spacing and LSP on the friction behavior and wear resistance of T9 tool steel are also analyzed and discussed.
Herein, a series of Ag coatings with different micro-dimples were fabricated on copper surfaces by laser surface texturing (LST) and magnetron sputtering. Multilayer graphene lubricating grease ...(MGLG) was prepared using multilayer graphene as an additive. The textured Ag coatings and MGLG were characterized. Moreover, the tribological and electrical performances of the textured Ag coatings under MGLG lubrication were investigated in detail. Results demonstrated that the textured Ag coating with an appropriate dimple diameter could exhibit improved tribological and electrical properties when compared to the non-textured Ag coating under MGLG lubrication. The characterization and analysis of the worn surfaces suggest that the synergetic effect of LST and MGLG contributes to these excellent tribological and electrical properties.
Friction and vibration behaviors of lubricated concentrated point contacts with surface texturing have been experimentally investigated under reciprocating motions. Ground, lapped and textured lapped ...flat surfaces are tested against polished ball surfaces. Coefficient of friction, surface temperature, electrical resistance and vibrations at the lubricated contacts have been measured and analyzed. In the presence of surface texture, the coefficient of friction reduces by 30% in some of the cases. Surface temperature distributions on reciprocating tracks have also been measured and compared. Vibrations associated with lubricated point contacts formed between textured surfaces/balls reduce significantly at resonance frequency in comparison to polished surfaces/balls.
► Significant reduction in coefficient of friction is observed with textured surface. ► Higher sliding velocities caused relatively more reduction in friction. ► Texturing caused decrease at the contact temperature at the turning points of motion. ► Overall vibration levels changed marginally in presence of surface texture. ► Contact resonance frequencies and their amplitudes reduce with surface texturing.
This article presents a new flow continuity model by modifying the traditional Elrod-Adams model. Both fully flooded lubrication and starved lubrication can be predicted using the universal model. In ...particular, for the starved lubrication problem, the inlet and outlet boundaries of oil film can be automatically determined. The discontinuity of the convection flow (or lubricant transport velocity) at the interface between the full lubricant film region and the partial lubricant film region is overcome by introducing a transition region. In addition, the two-dimensional version of the presented model is deduced. Furthermore, using the presented model, the results are presented to gain insight on the influence of starvation on the friction for the textured ring-liner system.
AISI 420 martensitic stainless steel is widely used in the mould industry due to its high tensile strength, hardness, and corrosion properties. Another requirement concerning any material used for ...this type of application is high thermal conductivity to minimise the time between consecutive injection cycles. The surfaces of some parts of the mould may be textured and reinforced with a material with higher thermal conductivity to achieve this aim. The results of a detailed study on the texturing of annealed 420 stainless steel using a Nd:YVO
fibre laser are presented in this work. The influence of the laser's processing parameters (laser power, scanning speed, number of passes, and line spacing) on the dimensions of the track, microstructure, and hardness of the modified surfaces was studied. Based on the continuity and dimensions of the machined grooves, several promising textures could be produced with laser power values from 5 to 30 W, scanning speeds of 500 to 2000 mm/s, 8 passes or more, and line spacings of 40 and 50 µm. High laser powers were responsible for the dissolution of chromium carbides in the laser tracks, the incorporation of chromium in austenite, and the consequent hardening of the microstructure.
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