Role of additive concentration in slow-speed sliding contact under boundary lubrication conditions

2019 ◽  
Vol 33 (11) ◽  
pp. 5361-5368 ◽  
Author(s):  
Bora Lee ◽  
Yonghun Yu ◽  
Dae-Seung Cho ◽  
Yongjoo Cho
Keyword(s):  
Boundary Lubrication ◽  
Sliding Contact ◽  
Additive Concentration ◽  
Slow Speed ◽  
Lubrication Conditions

Paper 8: The Fundamentals of Lubrication Processes

1966 ◽  
Vol 181 (12) ◽  
pp. 32-38
Author(s):  
D. Dowson ◽  
J. A. Robertson
Keyword(s):  
Boundary Lubrication ◽  
Operating Conditions ◽  
Lubrication Conditions

The authors outline the fundamental aspects of lubrication conditions and distinguish between hydrodynamic, elastohydrodynamic, and boundary lubrication. The discussion is concerned with the physics rather than the mathematics. The important lubricant properties and the role of bearing geometry are considered. This discussion of modern views on lubrication is perfectly general but operating conditions encountered in textile machinery are considered so that the various types of lubrication in practice can be identified.

The Slow-Speed Wear Behavior of Case-Carburized Gears Lubricated with NLGI 00 Grease under Boundary Lubrication Conditions

2014 ◽  
Vol 57 (3) ◽  
pp. 524-532 ◽  
Author(s):  
Hansjörg Schultheiss ◽  
Thomas Tobie ◽  
Klaus Michaelis ◽  
Bernd-Robert Höhn ◽  
Karsten Stahl
Keyword(s):  
Boundary Lubrication ◽  
Wear Behavior ◽  
Slow Speed ◽  
Lubrication Conditions

scholarly journals Comparison Between the Action of Nano-Oxides and Conventional EP Additives in Boundary Lubrication

Lubricants ◽  
2020 ◽  
Vol 8 (5) ◽  
pp. 54
Author(s):  
Valdicleide Silva Mello ◽  
Marinalva Ferreira Trajano ◽  
Ana Emilia Diniz Silva Guedes ◽  
Salete Martins Alves
Keyword(s):  
Friction Coefficient ◽  
Boundary Lubrication ◽  
Friction And Wear ◽  
Film Formation ◽  
Environmental Issues ◽  
Protective Film ◽  
Extreme Pressure ◽  
Extreme Pressure Additives ◽  
Environmental Requirements ◽  
Lubrication Conditions

Additives are essential in lubricant development, improving their performance by the formation of a protective film, thus reducing friction and wear. Some such additives are extreme pressure additives. However, due to environmental issues, their use has been questioned because their composition includes sulfur, chlorine, and phosphorus. Nanoparticles have been demonstrated to be a suitable substitute for those additives. This paper aims to make a comparison of the tribological performance of conventional EP additives and oxides nanoparticles (copper and zinc) under boundary lubrication conditions. The additives (nanoparticles, ZDDP, and sulfur) were added to mineral and synthetic oils. The lubricant tribological properties were analyzed in the tribometer HFRR (high frequency reciprocating rig), and during the test, the friction coefficient and percentual of film formation were measured. The wear was analyzed by scanning electron microscopy. The results showed that the conventional EP additives have a good performance owing to their anti-wear and small friction coefficient in both lubricant bases. The oxides nanoparticles, when used as additives, can reduce the friction more effectively than conventional additives, and displayed similar behavior to the extreme pressure additives. Thus, the oxide nanoparticles are more environmentally suitable, and they can replace EP additives adapting the lubricant to current environmental requirements.

Wear Behavior and Chemical Friction Modification in Binary-Additives System under Boundary-Lubrication Conditions

1981 ◽  
Vol 24 (4) ◽  
pp. 517-525 ◽  
Author(s):  
Masayuki Kagami ◽  
Masataro Yagi ◽  
Seiichiro Hironaka ◽  
Toshio Sakurai
Keyword(s):  
Boundary Lubrication ◽  
Wear Behavior ◽  
Lubrication Conditions

The role of surface topography and normal load in the initiation of ratchetting-peak friction, seizure, scuffing, and elastic shakedown

2021 ◽  
pp. 1-12
Author(s):  
Vimal Edachery ◽  
V. Swamybabu ◽  
Gurupatham Anand ◽  
Paramasamy Manikandan ◽  
Satish V. Kailas
Keyword(s):  
Steady State ◽  
Surface Topography ◽  
Sliding Wear ◽  
Friction And Wear ◽  
Critical Parameter ◽  
Normal Load ◽  
Sliding Direction ◽  
Elastic Shakedown ◽  
Lubrication Conditions

Abstract Surface topography is a critical parameter that can influence friction and wear in engineering applications. In this work, the influence of surface topography directionality on seizure and scuffing initiation during tribological interactions is explored. For this, unidirectional sliding wear experiments were carried out in immersed lubrication conditions for various normal loads. The tribological interactions were studied using EN31-60 HRC flats and SAE52100-60HRC pins in a sphere on flat configuration. The results show that, in some cases, the sliding interactions in the initial cycles lead to a high friction coefficient of up to ∼0.68 in lubricated conditions, which was termed as ‘peak friction’, and this was accompanied by scuffing. The existence of peak friction was found to be dependent on surface topography directionality, especially when the directionality in topography was parallel to the sliding direction. Continuous ratchetting was found to be the cause of peak friction which was accompanied by seizure and scuffing. When the topography directionality was perpendicular or independent of sliding direction, elastic shakedown occurred at earlier cycles and prevented peak friction initiation, scuffing and also facilitated for higher steady-state friction values.

Thin coatings with tetrahedral amorphous carbon structure and their behavior in boundary lubrication conditions

2020 ◽  
pp. 506-511
Author(s):  
V.D. Samusenko ◽  
I.A. Zavidovskii ◽  
O.A. Streletskii ◽  
I.A. Buyanovskii ◽  
M.M. Khrushchov ◽  
...  
Keyword(s):  
Amorphous Carbon ◽  
Boundary Lubrication ◽  
Carbon Structure ◽  
Thin Coatings ◽  
Tribological Tests ◽  
Tetrahedral Amorphous Carbon ◽  
Structural Peculiarities ◽  
Lubrication Conditions

The results of an investigation of the structural peculiarities of the thin ta-C coatings obtained by the method of impulse arc sputtering of graphite and of their tribological tests in boundary lubrication conditions are presented.

scholarly journals Design and verification of additional filtration for the application of ecological transmission and hydraulic fluids in tractorc

2013 ◽  
Vol 61 (5) ◽  
pp. 1305-1311 ◽  
Author(s):  
Pavel Máchal ◽  
Radoslav Majdan ◽  
Zdenko Tkáč ◽  
Bohuslav Stančík ◽  
Rudolf Abrahám ◽  
...  
Keyword(s):  
Chemical Elements ◽  
Main Role ◽  
Additive Concentration ◽  
Test Operation ◽  
Time Period ◽  
Medium Level ◽  
Agricultural Tractors ◽  
High Level ◽  
And Function

This contribution presents the design and function verification of additional filtration. It is intended for the common transmission and hydraulic oil filling of tractors. The main role of this filtration concept is to ensure a high level of oil cleanness as a condition for the application of ecologic fluids in tractors. The next one is to decrease the wear of lubricated tractor components, the degradation of oil and eventually to extend the interval of oil change. The designed additional filtering is characterized by ease installation through the use of quick couplings and hoses to the external hydraulic circuit. Therefore, the filtration is suitable for various tractor types. Filter element has been designed with the filter ability 1micron and the ability to separate to 0.5 dm3 of water from oil. Function of additional filtration was verified during the 150 engine hours of tractor operation. During this time period the oil contamination was evaluated on the basis of chemical elements content such as Fe, Cu, Si, Al, Ni, Mo and Cr. The additive concentration was evaluated on the basis of chemical elements content such as Ca, P and Zn. During the test operation of tractor the concentration decrease of chemical elements reached the values 25.53 % (Fe), 23.53 % (Si), 25 % (Al) and 5.5 % (Cu). The decrease of additive concentration reached only medium level (6.6 %). Therefore, the designed additional filtration doesn’t remove additives from oil. Based on the evaluation of the content of chemical elements (that representing contamination and additives), we can say that the designed filtering method is suitable for use in agricultural tractors.

Tribochemical Interactions of Friction Modifier and Antiwear Additives With CrN Coating Under Boundary Lubrication Conditions

2008 ◽  
Vol 130 (4) ◽  
Author(s):  
T. Haque ◽  
A. Morina ◽  
A. Neville ◽  
S. Arrowsmith
Keyword(s):  
Boundary Lubrication ◽  
Photoelectron Spectroscopy ◽  
Antiwear Additives ◽  
Low Friction ◽  
Friction Modifier ◽  
Crn Coating ◽  
Atomic Force ◽  
Surface Analysis Techniques ◽  
Positive Effect ◽  
Lubrication Conditions

In recent years, the optimized use of low friction nonferrous coatings under boundary lubrication conditions has become a challenge to meet the demands of improved fuel economy in automotive applications. This study presents the tribological performance of chromium nitride (CrN) coating using conventional friction modifier (moly dimer) and/or antiwear additive (zinc dialkyl dithiophosphate (ZDDP)) containing lubricants in a pin-on-plate tribometer. Using surface analysis techniques such as the atomic force microscope (AFM) and X-ray photoelectron spectroscopy (XPS), both topographical and chemical analyses of tribofilms were performed. This paper shows that ZDDP and moly dimer both give a positive effect for both low friction and antiwear performance in CrN/cast iron system. Both AFM and XPS analyses give evidence of the formation of ZDDP and moly dimer derived tribofilms on the CrN coating and thus support friction and wear results.

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