Surface Texturing Technology Research Articles

Numerical Research on Tribological Performance of Textured Liner Surface Under Different Combustion Modes

With the increasingly stringent requirements on energy saving and environmental-friendly for internal combustion (IC) engine, new concepts like novel combustion mode and surface texturing technology have emerged. In order to have deep understanding about the application effects of surface texturing into IC engine with new combustion mode, a mixed lubrication calculation model considering surface textures on cylinder liner together with different combustion modes has been built in the present work based on a four-cylinder diesel engine. The numerical research was conducted on the change of the surface tribological performance of textured cylinder liner under different combustion modes. The simulation results indicate that compared with the conventional combustion (CC) mode, the combustion phase of premixed charge combustion ignition (PCCI) mode and retarded injection (RI) mode varies and their in-cylinder peak pressure is different at the beginning of power stroke due to different injection strategies applied, which lead to significant differences between piston ring radial working loads. Near TDC, the mixed lubrication duration of PCCI and RI mode increases slightly in comparison to that of CC mode, and these three boundary lubrication durations are almost same. However, the thickness of lubricant film between friction pair of three modes is quite different, resulting in their different tribological properties. Among these parameters, the dimensionless total friction force (DTFF) and the dimensionless friction work of PCCI mode increase by 82.37% and 18.41% at most, respectively, while those of RI mode decrease by 36.50% and 12.45% at most, respectively, compared with the same parameters of CC mode. Therefore, the variations in tribological property of the textured cylinder liner–piston ring (CLPR) with different combustion modes should not be ignored.

Micro/Nanotexture Design for Improving Tribological Properties of Cr/GLC Films in Seawater

ABSTRACTMicrodimples with different diameters and Cr/graphite-like carbon (GLC) films were fabricated on silicon by laser surface texturing and magnetron sputtering technology, respectively. The texturing effects on the microstructures and tribological performance in seawater were comparatively investigated. The results showed that both the friction coefficients and wear rates in seawater decreased with an increase in dimple diameter in the lower range and then increased with a further increase in diameter. The Cr/GLC film with an appropriate diameter of dimples (1.5 µm) is effective in enhancing the tribological properties due to entrapment of wear particles and seawater in the dimples. In addition, the roughness and graphitization contact area have obvious effects on the wear resistance. If the surface roughness is too high, the graphitization contact area will decrease, and the ratio of minimum aqueous film thickness to the surface roughness is so small that the load is almost totally borne by the boundary film.

Selection of micro-fabrication techniques on stainless steel sheet for skin friction

AbstractThis review gives a concise introduction to the state-of-art techniques used for surface texturing, e.g., wet etching, plasma etching, laser surface texturing (LST), 3D printing, etc. In order to fabricate deterministic textures with the desired geometric structures and scales, the innovative texturing technologies are developed and extended. Such texturing technology is an emerging frontier with revolutionary impact in industrial and scientific fields. With the help of the latest fabrication technologies, surface textures are scaling down and more complex deterministic patterns may be fabricated with desired functions, e.g., lotus effect (hydrophobic), gecko feet (adhesive), haptic tactile, etc. The objective of this review is to explore the surface texturing technology and its contributions to the applications.

Hydrodynamic Lubrication and Load Carrying Capacity Analysis of Laser Surface Texturing Valve Core

Take water hydraulic slide valve core as the research object. Laser surface texturing (LST) technology was used to improve the valve core carrying capacity and hydrodynamic lubrication characteristics, which can process micro-texture on the surface of the core. And CFD method was taken to calculate flow field of smooth and laser surface texturing core respectively. For studying the influence of valve core micro-texture and valve core overlap lengths on hydrodynamic lubrication characteristic and carrying capacity of the core, core surface pressure distribution, surface pressure and friction force curves were drawn. Results show: The smooth valve core does not produce hydrodynamic lubrication effect, but textured valve core can bring the oil film load capacity, so as to make the effect of mixed friction between valve core and sleeve weaken. And along with the decrease of the core overlap length, the carrying capacity on the surface of the textured valve core does not decrease but increase when the valve core overlap length amount is greater than 2.5mm.The results provide important theoretical reference of studying and applying LST process technology to the valve core friction pair’s lubrication performance.

Characterisation of group behaviour surface texturing with multi-layers fitting method

Surface texturing was widely applied in improving the tribological properties of mechanical components, but study of measurement of this technology was still insufficient. This study proposed the multi-layers fitting (MLF) method to characterise the dimples array texture surface. Based on the synergistic effect among the dimples, the 3D morphology of texture surface was rebuilt by 2D stylus profiler in the MLF method. The feasible regions of texture patterns and sensitive parameters were confirmed by non-linear programming, and the processing software of MLF method was developed based on the Matlab®. The characterisation parameters system of dimples was defined mathematically, and the accuracy of MLF method was investigated by comparison experiment. The surface texture specimens were made by laser surface texturing technology, in which high consistency of dimples’ size and distribution was achieved. Then, 2D profiles of different dimples were captured by employing Hommel-T1000 stylus profiler, and the data were further processed by MLF software to rebuild 3D morphology of single dimple. The experiment results indicated that the MLF characterisation results were similar to those of Wyko T1100, the white light interference microscope. It was also found that the stability of MLF characterisation results highly depended on the number of captured cross-sections.

A novel strategy to enhance the tribological properties of Cr/GLC films in seawater by surface texturing

In this paper, the patterns of micro-dimples with different area densities and the Cr/GLC films were fabricated by laser surface texturing and magnetron sputtering technology, respectively. The morphologies and surface chemical states of the Cr/GLC films were characterized by AFM, SEM, and XPS. The effects of dimple area density on the tribological behavior of Cr/GLC films under seawater condition were investigated by UMT-3 tribometer in a ball-on-plate reciprocating mode. The experimental results showed that the Cr/GLC film was mainly composed by Cr–C and C–C bonds. Both the friction coefficients and wear rates of the Cr/GLC films in seawater decreased with the increase of dimple area densities in the lower range, whereas, they were constant when the dimple area densities further increased. The Cr/GLC films with proper dimple area density (G3 film) were effective in enhancing the tribological properties because of the entrapment of graphitized particles and seawater in the dimples. The graphitized particles can reduce the strong adhesive interaction between contact surfaces, resulting in the low frictional shear resistance during sliding process. Furthermore, Ca2+ and Mg2+ in seawater will be deposited on the counterface in the form of Mg(OH)2 and CaCO3, which with sludge-like matters have some lubricating effects. At the same time, the Cr/GLC films with low dimple area densities exhibited low surface roughness, which could decrease the resistance in sliding process.

Tribological behavior of femtosecond laser textured surfaces of 20CrNiMo/beryllium bronze tribo-pairs

Purpose – This paper aims to carry out tribological experiments to explore the applications of femtosecond laser surface texturing technology on rock bit sliding bearing to enhance the lifetime and working performance of rock bit sliding bearing under high temperature and heavy load conditions. Design/methodology/approach – Surface textures on beryllium bronze specimen were fabricated by femtosecond laser ablation (800 nm wavelength, 40 fs pulse duration, 1 kHz pulse repetition frequency), and then the tribological behaviors of pin-on-disc configuration of rock bit bearing were performed with 20CrNiMo/beryllium bronze tribo-pairs under non-Newtonian lubrication of rock bit grease. Findings – The results showed that the surface texture on beryllium bronze specimens with specific geometrical features can be achieved by optimizing femtosecond laser processing via adjusting laser peak power and exposure time; more than 52 per cent of friction reduction was obtained from surface texture with a depth-to-diameter ratio of 0.165 and area ratio of 5 per cent at a shear rate of 1301 s−1 under the heavy load of 20 MPa and high temperature of 120°C, and the lubrication regime of rock bit bearing unit tribo-pairs was improved from boundary to mixed lubrication, which indicated that femtosecond laser ablation technique showed great potential in promoting service life and working performance of rock bit bearing. Originality/value – Femtosecond laser-irradiated surface texture has the potential possibility for application in rock bit sliding bearing to improve the lubrication performance. Because proper micro dimples showed good lubrication and wear resistance performance for unit tribo-pairs of rock bit sliding bearing under high temperature, heavy load and non-Newtonian lubrication conditions, which is very important to improve the efficiency of breaking rock and accelerate the development of deep-water oil and gas resources.

Blackening of magnesium alloy using femtosecond laser.

Magnesium alloy, a potential structural and biodegradable material, has been increasingly attracting attention. In this paper, two structures with enhanced light absorption on an AZ31B magnesium surface are fabricated by femtosecond laser texturing. Laser power and the number of laser pulses are mainly investigated for darkening effect. After irradiation, surface characteristics are analyzed by a scanning electron microscope equipped with an energy dispersive spectrometer and laser scanning confocal microscope. The darkening effect is investigated by a spectrophotometer with an integrating sphere. Microgroove and stripe structures are obtained, which are covered with homogeneous nanoprotrusions and nanoparticles. The main surface chemical composition after laser ablation is MgO. The optimal light absorption in the visible range (wavelength of 400-800nm) reaches about 98%, which is significantly improved compared with the untreated surface. The enhanced light absorption is mainly attributed to surface structure. Femtosecond laser surface texturing technology offers potential in the application of stealth technology, airborne devices, and biomedicine.

Nanotexturing of Silicon by Metal-Assisted Chemical Etching

This paper describes the method of metal assisted chemical etching (MacEtch) as an efficient approach for structuring the silicon surface with the ability to manage effectively the geometric parameters of the structures and their distribution on the surface of substrate. The surface texturing technology was presented and the structured silicon surfaces with regular and irregular types of surfaces have been obtained. This technology can be used for nanotexturing of the surface of silicon photovoltaic converters. The model of photovoltaic converter based on the crater-textured silicon surface with high efficiency was presented.

Tribological behaviors of two micro textured surfaces generated by vibrating milling under boundary lubricated sliding

Surface texture technology is widely used in various friction pairs to obtain good lubrication. However, ever present researches are mainly focused on regular and simple texture shapes such as dimples and grooves. Few works on complex micro texture have been reported due to preparing difficulty. In this paper, two surfaces with complex micro texture, which are micro scale textured (MST) surface and micro furrow textured (MFT) surface, are prepared by ultrasonic vibration-assisted milling (UVAM) method. Also, their tribological behaviors under starved oil lubrication and reciprocating sliding condition are experimentally investigated with a smooth sample as comparison. Experimental results indicate that although the application of ultrasonic vibration leads to the increase of roughness of MST and MFT surfaces, both the two machined micro textures contribute to the improvement of lubricant film strength, and MFT surface has better tribological performance than that of MST surface. As a result, under test conditions, micro texture formed by UVAM method can greatly improve the tribological property of friction surface, especially for its bearing capacity and wear resistance.

Global energy consumption due to friction in trucks and buses

In this paper, we report the global fuel energy consumption in heavy-duty road vehicles due to friction in engines, transmissions, tires, auxiliary equipment, and brakes. Four categories of vehicle, representing an average of the global fleet of heavy vehicles, were studied: single-unit trucks, truck and trailer combinations, city buses, and coaches. Friction losses in tribocontacts were estimated by drawing upon the literature on prevailing contact mechanics and lubrication mechanisms. Coefficients of friction in the tribocontacts were estimated based on available information in the literature for four cases: (1) the average vehicle in use today, (2) a vehicle with today׳s best commercial tribological technology, (3) a vehicle with today׳s most advanced technology based upon recent research and development, and (4) a vehicle with the best futuristic technology forecasted in the next 12 years. The following conclusions were reached:•In heavy duty vehicles, 33% of the fuel energy is used to overcome friction in the engine, transmission, tires, auxiliary equipment, and brakes. The parasitic frictional losses, with braking friction excluded, are 26% of the fuel energy. In total, 34% of the fuel energy is used to move the vehicle.•Worldwide, 180,000 million liters of fuel was used in 2012 to overcome friction in heavy duty vehicles. This equals 6.5millionTJ/a; hence, reduction in frictional losses can provide significant benefits in fuel economy. A reduction in friction results in a 2.5 times improvement in fuel economy, as exhaust and cooling losses are reduced as well.•Globally a single-unit truck uses on average 1500l of diesel fuel per year to overcome friction losses; a truck and trailer combination, 12,500l; a city bus, 12,700l; and a coach, 7100l.•By taking advantage of new technology for friction reduction in heavy duty vehicles, friction losses could be reduced by 14% in the short term (4 to 8 years) and by 37% in the long term (8 to 12 years). In the short term, this would annually equal worldwide savings of 105,000 million euros, 75,000 million liters of diesel fuel, and a CO2 emission reduction of 200 million tones. In the long term, the annual benefit would be 280,000 million euros, 200,000 million liters of fuel, and a CO2 emission reduction of 530 million tonnes.•Hybridization and electrification are expected to penetrate only certain niches of the heavy-duty vehicle sector. In the case of city buses and delivery trucks, hybridization can cut fuel consumption by 25% to 30%, but there is little to gain in the case of coaches and long-haul trucks. Downsizing the internal combustion engine and using recuperative braking energy can also reduce friction losses.•Electrification is best suited for city buses and delivery trucks. The energy used to overcome friction in electric vehicles is estimated to be less than half of that of conventional diesel vehicles.Potential new remedies to reduce friction in heavy duty vehicles include the use of advanced low-friction coatings and surface texturing technology on sliding, rolling, and reciprocating engine and transmission components, new low-viscosity and low-shear lubricants and additives, and new tire designs that reduce rolling friction.

Improving the tribological performance of a-C:H film in a high vacuum by surface texture

In this study, a new synergy lubricating system was designed by combining the surface texture and film deposition technology to improve the tribological performances of amorphous hydrogenated carbon (a-C:H) films in a ball-on-disk tribometer under vacuum conditions. Tribological behaviours of the untextured and textured films in a vacuum environment were investigated in detail. The results suggest that the wear life of a-C:H film is dramatically prolonged by surface texture with appropriate interval distances. A comprehensive friction and wear mechanism model is proposed based on substantial structural characterization and wear trace analyses. In this model, the generation of the hard and brittle wear debris is considered as the key unfavourable factor resulting in the rapid failure of a-C:H films, while the surface texture is beneficial in reducing the formation of wear debris, and further trapping it during the friction process.

Friction and wear performance of laser peen textured surface under starved lubrication

Laser peen texturing (LPT), which is a new surface texturing technology, was proposed to fabricate micro-dimple arrays on copper surface. Pin-on-disk experiments were conducted under different normal loads and sliding speeds to investigate friction and wear behaviors of untextured and textured samples in starved lubrication. It was found that friction performance of the surface is improved significantly after LPT. Microscope observation and EDS analysis showed that textured surface could reduce both abrasive and adhesive wear as compared to untextured surface. Results also indicated that an optimum texture density might exist at which surface shows the best friction and wear behavior.

Theoretical and Experimental Research on Lubrication Performance of Laser Surface Texturing Cylinder Liner

By applying the laser surface texturing technique to the engine cylinder liner surface,a mixed lubrication theoretical model of cylinder liner-piston ring is established.The model is calculated to reveal the influence of laser surface texturing on tribology performance with barrel-shaped ring.The results show that after the laser surface texturing,the lubrication and friction performance of the cylinder is improved,the effect of dimple is superior to the groove texturing,the minimum oil ratio in the middle regions of the strokes is increased by 29%,while the friction peak is decreased about 30%.By comparing the engine bench test,it is found that after the surface texture cylinder liner,the engine cylinder fuel consumption shows a declining trend relative to the original engine,the effect is improved significantly at a low speed,the maximum rate of fuel consumption is reduced 9.8 g/(kW h),a decline of 4.62%,which confirms that the surface texture technology is effective for reducing engine friction loss.Meanwhile,the other engine performance indicators also are improved to some extent,air leakage,smoke,oil consumption and other parameters is declined,the smoke is declined obviously,the largest leakage is decreased by 34.6%,and the oil consumption is reduced by 33.8%.

Global energy consumption due to friction in passenger cars

This study presents calculations on the global fuel energy consumption used to overcome friction in passenger cars in terms of friction in the engine, transmission, tires, and brakes. Friction in tribocontacts was estimated according to prevailing contact mechanisms such as elastohydrodynamic, hydrodynamic, mixed, and boundary lubrication. Coefficients of friction in the tribocontacts were estimated based on available information in the literature on the average passenger car in use today, a car with today’s advanced commercial tribological technology, a car with today’s best advanced technology based upon recent research and development, and a car with the best technology forecasted in the next 10 years. The following conclusions were reached:•In passenger cars, one-third of the fuel energy is used to overcome friction in the engine, transmission, tires, and brakes. The direct frictional losses, with braking friction excluded, are 28% of the fuel energy. In total, 21.5% of the fuel energy is used to move the car.•Worldwide, 208,000 million liters of fuel (gasoline and diesel) was used in 2009 to overcome friction in passenger cars. This equals 360 million tonne oil equivalent per year (Mtoe/a) or 7.3millionTJ/a. Reductions in frictional losses will lead to a threefold improvement in fuel economy as it will reduce both the exhaust and cooling losses also at the same ratio.•Globally, one passenger car uses on average of 340l of fuel per year to overcome friction, which would cost 510 euros according to the average European gas price in 2011 and corresponds to an average driving distance of 13,000km/a.•By taking advantage of new technology for friction reduction in passenger cars, friction losses could be reduced by 18% in the short term (5–10 years) and by 61% in the long term (15–25 years). This would equal worldwide economic savings of 174,000 million euros and 576,000 million euros, respectively; fuel savings of 117,000 million and 385,000 million liters, respectively; and CO2 emission reduction of 290 million and 960 million tonnes, respectively.•The friction-related energy losses in an electric car are estimated to be only about half those of an internal combustion passenger car.Potential actions to reduce friction in passenger cars include the use of advanced coatings and surface texturing technology on engine and transmission components, new low-viscosity and low-shear lubricants and additives, and tire designs that reduce rolling friction.

Experiment Study on Tribological Properties of the Coating with Different Surface Textures

This paper is about the KF301/WS2 modified lubricating wear-resisting coating which is prepared by supersonic plasma spraying, laser remelting and surface texturing technology, tribological characteristic of KF301/WS2 lubricating wear-resisting coating of four different (round pit, diamond, parallel and intermittence) tracks and part laser remelting is studied under room temperature. Research shows: textures of different tracks have a certain influence on friction factor of coating’s surface and abrasion loss. Friction coefficient of mouldling surface of broken texture is about 0.012 in the initial stages, while friction coefficient of round pit texture is about 0.0085. Round pit, diamond and parallel microtopography make friction state enter stabilization quickly, effectively restraining the wave of abrasion loss. When wear time reaches to 1 hour, abrasion loss of broken texture is 0.03mg, while abrasion loss of round pit texture is about 0.015mg. Tribological properties, from high to low, in turn, are round pits, diamond, parallel and broken texture.

Study on the Lubrication and Antifriction Mechanism of Low Frictional Self-Lubricating Wear-Resisting Coating

This paper is about the lubricating wear-resisting coating KF301/WS2 and round pit texturing modified coating KF301/WS2 which are prepared by supersonic plasma spraying, laser remelting and surface texturing technology, tribological characteristics of two kinds of coatings are studied under room temperature, according to this, it is discussed for lubrication antifriction mechanism. The research shows: round pit texture has a certain influence on friction factor of coating’s surface and abrasion loss. Friction coefficient of untextured surface is about 0.0138 in the initial stages, while friction coefficient of round pit texture is about 0.01, compared with the former, the latter decreases 27%; when wear time reaches to 1 hour, abrasion loss of untextured surface is 0.0026mg, while abrasion loss of round pit texture is about 0.013mg, compared with the former, the latter decreases 50%. The lubricant antifriction performance of round pit texture is higher than untextured surface, this is because friction coefficient of coating is decreased as the change of the third-body bed, and round pit micro moulding can collect abrasive particle, decreasing the influence of abrasive particle.

Surface Texturing Technology by Laser Honing Based on Hydrodynamic Lubrication

The laser honing technique is a new surface texturing technique. As the piston ring at the top or lower oil attachment point works under worse lubrication condition, its wear increases severely, laser texturing was used to the piston ring/liner, lineary extending grooves and regular arranged dimples with predetermined parameters was well-matched with the needs of lubrication. The effects of different dimple shapes, such as sphere coronal, combined sphere coronal ,columnar, hexahedral, and trapezoidal dimples was analyzed by the theory of hydrodynamic lubrication. It was deduced that trapezoidal dimples are fit for only single running orientation and sphere coronal and combined sphere coronal dimples are fit for double running orientations. The experimental researches show that laser texturing not only can reduce the oil consumption and the cost of engine but also can prolong its work life.

Investigation into LST and its Novel Application in Mould

Laser surface texturing (LST) technology that is firstly used in rollers, is a specialized surface engineering process capable of enhancing the surface material properties, wear resistance, fretting fatigue life and reducing friction. This practical technology of the LST process is based on a pulsating laser beam that, by material ablation, generates the optimum topographical surface. In order to exploit the full potential of the process, a great amount of research has explored from the material removal mechanics to the development of the LST process. This paper reports on the LST research involving the LST technology surveying process optimization, LST equipment and its industrial applications. The paper also highlights the forming theory describing the skin-pass process of transferring the textured roller’s surface structure onto the steel sheet, and the laser-matter interaction that occurs when and intense laser beam is tightly focused in the workpiece surface. It presents the influence of various factors affecting the textured workpiece performance together with the investigations into tribology of textured components. The paper also discusses these developments and some fundamental on future LST research.

The effect of laser surface texturing on frictional performance of face seal

Laser surface texturing technology has some advantages in reducing friction and wear of mechanical parts in industry. In this paper, a Nd:YAG laser was used to generate micropores on T8 steel surface and the structure and morphology features of surface micropores were observed. Tribological experiments were conducted with a ring-on-disc tester under various loads and speeds. It is shown that the maximum PV value of face seal can be increased by hydrodynamic effect of micropores.