scholarly journals Lubrication improvement and friction reduction of DLC-coated sliding surfaces by in-process structuring and post polishing

Tribotest ◽  
10.1002/tt.55 ◽  
2008 ◽  
Vol 14 (2) ◽  
pp. 97-112 ◽  
Author(s):  
P. Andersson ◽  
J. Koskinen ◽  
S. Varjus ◽  
J. Kolehmainen ◽  
S. Tervakangas ◽  
...  
Keyword(s):  
Friction Reduction ◽  
Sliding Surfaces

THE EFFECTS OF SURFACE ROUGHNESS ON FRICTION REDUCTION AS THE RESULT OF SURFACE TEXTURING BY ABRASIVE JET MACHINING

Tribologia ◽  
2016 ◽  
Vol 267 (3) ◽  
pp. 195-204
Author(s):  
Sławomir WOŚ ◽  
Waldemar KOSZELA ◽  
Paweł PAWLUS
Keyword(s):  
Surface Roughness ◽  
Friction Force ◽  
Surface Texturing ◽  
Frictional Resistance ◽  
Friction Reduction ◽  
Textured Surfaces ◽  
Sliding Surfaces ◽  
Abrasive Jet Machining ◽  
Oil Pockets

Various machining methods are currently used to obtain the best co-action of sliding surfaces. Application of two-process surfaces led to a decrease of frictional resistance. Textured surfaces after abrasive jest machining are practical examples of two-process topographies. The results of the application of textured discs with the same array of oil pockets of similar sizes, but with different roughness in areas free of dimples, are presented in this paper. It was determined that after this type of machining, the effect of the friction force decrease was caused by surface texturing.

scholarly journals Towards a Polymer-Brush-Based Friction Modifier for Oil

2021 ◽  
Vol 69 (4) ◽  
Author(s):  
Tobias A. Gmür ◽  
Joydeb Mandal ◽  
Juliette Cayer-Barrioz ◽  
Nicholas D. Spencer
Keyword(s):  
Block Copolymers ◽  
Raft Polymerization ◽  
Film Formation ◽  
Polymer Brush ◽  
Friction Reduction ◽  
Friction Modifier ◽  
Molecular Weights ◽  
Sliding Surfaces ◽  
Reversible Addition ◽  
Anchoring Groups

AbstractTo meet the need for oil-compatible friction modifier additives that can significantly reduce energy consumption in the boundary-lubrication regime, a macromolecular design approach has been taken. The aim was to produce a lubricious polymer film on the sliding surfaces. A series of readily functionalizable block copolymers carrying an oleophilic poly(dodecyl methacrylate) block and a functionalizable poly(pentafluorophenyl methacrylate) block of various lengths was synthesized by means of reversible addition-fragmentation chain-transfer (RAFT) polymerization. The poly(pentafluorophenyl methacrylate) block was used to attach surface-active nitrocatechol anchoring groups to the polymer. The friction-reduction properties of these polymers were assessed with 0.5 wt% solutions in hexadecane by means of rolling-sliding macroscopic tribological tests. Block copolymers with roughly equal block lengths and moderate molecular weights were significantly more effective at friction reduction than all other architectures investigated. They also displayed lower friction coefficients than glycerol monooleate—a commercially used additive. The film-formation ability of these polymers was examined using a quartz-crystal microbalance with dissipation (QCM-D), by monitoring their adsorption onto an iron oxide-coated QCM crystal. The polymer with highest lubrication efficiency formed a thin film of ~ 17 nm thickness on the crystal, indicating the formation of a polymer brush. Interferometric rolling-sliding experiments with the same polymer showed a separating film thickness of ~ 20 nm, which is consistent with the QCM-D value, bearing in mind the compression of the adsorbed layers on the two sliding surfaces during tribological testing. Graphical Abstract

Lubricated Friction Reduction by Spiral-Groove-Shape Nano-Texturing

2012 ◽  
Vol 516 ◽  
pp. 431-436 ◽  
Author(s):  
Yusuke Tanaka ◽  
Kazuma Okada ◽  
Tomoko Hirayama ◽  
Takashi Matsuoka ◽  
Hiroshi Sawada ◽  
...  
Keyword(s):  
Femtosecond Laser ◽  
Tribological Properties ◽  
Friction Reduction ◽  
Fluid Film ◽  
Spiral Groove ◽  
Low Friction ◽  
Surface Textures ◽  
Lubrication Film ◽  
Sliding Surfaces ◽  
Effect Of Surface

To effectively reduce the friction in machines operating under lubrication, the sliding surfaces should be fully fluid-film lubricated. Under the full fluid-film lubricated conditions, the upper surface is completely supported by the lubrication film formed in the gap between the surfaces, resulting in low friction and no wear. Surface texuturing is a promising way to modify the tribological properties of sliding surfaces, and a technique for fabricating surface textures with a nanometre-order depth using a femtosecond laser can be used to easily and quickly produce periodic grooves in metal surfaces. It can thus be applied to industrial sliding surfaces to improve their tribological properties. The purpose of the study is to verify the effect of surface nanotextures fabricated using a femtosecond laser to reduce friction under lubrication. As a result, the two disks continued to operate under full fluid-film lubricated conditions even when the bearing clearance became quite small, less than 200 nm. Our testing showed that grooves with a nanometre-order depth can support a higher load than ones with a micrometre-order depth, and we proved that nanotexture can expand the full-lubricated condition.

Interaction of tungsten in dry sliding against steel under high density electric current

2019 ◽  
pp. 101-109 ◽  
Author(s):  
M. I. Aleutdinova ◽  
V. V. Fadin ◽  
Yu. P. Mironov
Keyword(s):  
Electrical Contact ◽  
Analysis Data ◽  
Dry Sliding ◽  
Sliding Surface ◽  
X Ray ◽  
Sliding Surfaces ◽  
Quenched Steel ◽  
Sliding Electrical Contact ◽  
A Current ◽  
Tungsten Steel

The possibility of creating a wear-resistant dry sliding electrical contact tungsten/steel was studied. It was shown that tungsten caused severe wear of the quenched steel counterbody due to unlimited plastic flow of its surface layer at a current density up to 150 A/cm2 . This indicated the impossibility of achieving satisfactory characteristics of such a contact. Low electrical conductivity and wear resistance of the contact tungsten/steel were presented in comparison with the known high copper/steel contact characteristics under the same conditions. X-ray phase analysis data of the steel sliding surfaces made it possible to state that the cause of the unsatisfactory sliding of tungsten was the absence of the necessary concentration of FeO oxide on the sliding surface of the steel. 

Estimating Friction Reduction ForCasing Operations in High-Angle Wells in The Arctic Region - A Russia Case History

2011 ◽  
Author(s):  
Chimerebere Onyekwere Nkwocha ◽  
Evgeny Glebov ◽  
Alexey Zhludov ◽  
Sergey Galantsev ◽  
David Kay
Keyword(s):  
Case History ◽  
Arctic Region ◽  
Friction Reduction ◽  
The Arctic ◽  
High Angle ◽  
The Arctic Region

scholarly journals The Rotating Liner Engine (RLE) Diesel Prototype: Reducing Internal Engine Friction by about 40% under Idle Conditions

2021 ◽  
Vol 11 (2) ◽  
pp. 779
Author(s):  
Dimitrios Dardalis ◽  
Amiyo Basu ◽  
Matt J. Hall ◽  
Ronald D. Mattthews
Keyword(s):  
Internal Combustion Engines ◽  
Hydrodynamic Lubrication ◽  
Cylinder Liner ◽  
Friction Reduction ◽  
Contact Boundary ◽  
Metal Contact ◽  
Load Testing ◽  
Gas Leakage ◽  
Brake Mean Effective Pressure ◽  
Economy Benefit

The Rotating Liner Engine (RLE) concept is a design concept for internal combustion engines, where the cylinder liner rotates at a surface speed of 2–4 m/s in order to assist piston ring lubrication. Specifically, we have evidence from prior art and from our own research that the above rotation has the potential to eliminate the metal-to-metal contact/boundary friction that exists close to the piston reversal areas. This frictional source becomes a significant energy loss, especially in the compression/expansion part of the cycle, when the gas pressure that loads the piston rings and skirts is high. This paper describes the Diesel RLE prototype constructed from a Cummins 4BT and the preliminary observations from initial low load testing. The critical technical challenge, namely the rotating liner face seal, appears to be operating with negligible gas leakage and within the hydrodynamic lubrication regime for the loads tested (peak cylinder pressures of the order of 100 bar) and up to about 10 bar BMEP (brake mean effective pressure). Preliminary testing has proven that the metal-to-metal contact in the piston assembly mostly vanished, and a friction reduction at idle conditions of about 40% as extrapolated to a complete engine has taken place. It is expected that as the speed increases, the friction reduction percentage will diminish, but as the load increases, the friction reduction will increase. The fuel economy benefit over the US Heavy-Duty driving cycle will likely be of the order of 10% compared to a standard engine.

scholarly journals On the Microstructural, Mechanical and Tribological Properties of Mo-Se-C Coatings and Their Potential for Friction Reduction against Rubber

Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1336
Author(s):  
Jorge Caessa ◽  
Todor Vuchkov ◽  
Talha Bin Yaqub ◽  
Albano Cavaleiro
Keyword(s):  
Carbon Content ◽  
Friction And Wear ◽  
Current Mode ◽  
Friction Reduction ◽  
Transition Metal Dichalcogenide ◽  
Butadiene Rubber ◽  
Wear Rates ◽  
Mechanical And Tribological Properties ◽  
The Coefficient Of Friction ◽  
Pin On Disk

Friction and wear contribute to high energetic losses that reduce the efficiency of mechanical systems. However, carbon alloyed transition metal dichalcogenide (TMD-C) coatings possess low friction coefficients in diverse environments and can self-adapt to various sliding conditions. Hence, in this investigation, a semi-industrial magnetron sputtering device, operated in direct current mode (DC), is utilized to deposit several molybdenum-selenium-carbon (Mo-Se-C) coatings with a carbon content up to 60 atomic % (at. %). Then, the carbon content influence on the final properties of the films is analysed using several structural, mechanical and tribological characterization techniques. With an increasing carbon content in the Mo-Se-C films, lower Se/Mo ratio, porosity and roughness appeared, while the hardness and compactness increased. Pin-on-disk (POD) experiments performed in humid air disclosed that the Mo-Se-C vs. nitrile butadiene rubber (NBR) friction is higher than Mo-Se-C vs. steel friction, and the coefficient of friction (CoF) is higher at 25 °C than at 200 °C, for both steel and NBR countersurfaces. In terms of wear, the Mo-Se-C coatings with 51 at. % C showed the lowest specific wear rates of all carbon content films when sliding against steel. The study shows the potential of TMD-based coatings for friction and wear reduction sliding against rubber.

scholarly journals Fast laser surface texturing of spherical samples to improve the frictional performance of elasto-hydrodynamic lubricated contacts

Friction ◽  
2021 ◽  
Author(s):  
G. Boidi ◽  
P. G. Grützmacher ◽  
A. Kadiric ◽  
F. J. Profito ◽  
I. F. Machado ◽  
...  
Keyword(s):  
Surface Texturing ◽  
Hydrodynamic Pressure ◽  
Friction Reduction ◽  
Laser Surface Texturing ◽  
Textured Surfaces ◽  
Engineering Applications ◽  
Lubricated Contacts ◽  
Fluid Uptake ◽  
Direct Laser ◽  
Frictional Performance

AbstractTextured surfaces offer the potential to promote friction and wear reduction by increasing the hydrodynamic pressure, fluid uptake, or acting as oil or debris reservoirs. However, texturing techniques often require additional manufacturing steps and costs, thus frequently being not economically feasible for real engineering applications. This experimental study aims at applying a fast laser texturing technique on curved surfaces for obtaining superior tribological performances. A femtosecond pulsed laser (Ti:Sapphire) and direct laser interference patterning (with a solid-state Nd:YAG laser) were used for manufacturing dimple and groove patterns on curved steel surfaces (ball samples). Tribological tests were carried out under elasto-hydrodynamic lubricated contact conditions varying slide-roll ratio using a ball-on-disk configuration. Furthermore, a specific interferometry technique for rough surfaces was used to measure the film thickness of smooth and textured surfaces. Smooth steel samples were used to obtain data for the reference surface. The results showed that dimples promoted friction reduction (up to 20%) compared to the reference smooth specimens, whereas grooves generally caused less beneficial or detrimental effects. In addition, dimples promoted the formation of full film lubrication conditions at lower speeds. This study demonstrates how fast texturing techniques could potentially be used for improving the tribological performance of bearings as well as other mechanical components utilised in several engineering applications.

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