Performance Improvement Under Boundary Lubrication Conditions Using Slider Bearings With Silicon Nitride/Steel in High Torque Hydraulic Motors

1999 ◽  
Vol 122 (1) ◽  
pp. 348-353 ◽  
Author(s):  
O. Isaksson ◽  
R. Larker
Keyword(s):  
Silicon Nitride ◽  
Boundary Lubrication ◽  
Static Friction ◽  
Chromium Steel ◽  
Gray Iron ◽  
Dynamic Coefficients ◽  
Hydraulic Motors ◽  
Surface Topographies ◽  
Intermediate Surface ◽  
Lubrication Conditions

The influence of materials and surface topography on static and dynamic coefficients of friction was experimentally investigated in a test apparatus under boundary and mixed lubrication conditions. Specimen materials were gray iron and silicon nitride Si3N4 of different surface topographies, sliding against chromium steel at a maximum Hertzian line contact pressure of 50 MPa. The lubricant was a standard mineral-based hydraulic fluid (ISO VG 68) held at +40°C or −28°C. The static and dynamic coefficients of friction under boundary lubrication conditions were both significantly reduced by the change from grey iron to silicon nitride as sliding material against Cr-steel, while the lowest static friction with Si3N4 was found for an intermediate surface roughness. [S0742-4787(00)04601-4]

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

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.

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.

Friction Coefficients Measured at Lubricated Planar Contacts During Start-Up

1988 ◽  
Vol 110 (3) ◽  
pp. 533-538 ◽  
Author(s):  
E. H. Gassenfeit ◽  
A. Soom
Keyword(s):  
Static Friction ◽  
Transient Behavior ◽  
Molybdenum Disulphide ◽  
Friction Behavior ◽  
Friction Characteristic ◽  
Friction Coefficients ◽  
Motion Data ◽  
Start Up ◽  
Planar Contact ◽  
Lubrication Conditions

Measurements of instantaneous coefficients of friction and associated motions during start-up at a planar contact are presented for four different lubrication conditions. The various patterns of transient behavior are discussed. Difficulties in interpreting static friction coefficients during rapidly applied tangential loads are described in relation to the motion data. It is shown that a molybdenum disulphide grease yields a friction characteristic that is quite different from either dry or boundary lubricated conditions in the presence of liquid lubricants. Transition distances from a static or maximum initial friction to kinetic conditions are examined and found to be considerably longer than had been previously found for concentrated contacts. Some suggestions regarding future studies of unsteady friction behavior are made.

Tribological evaluation of piston skirt/cylinder liner contact interfaces under boundary lubrication conditions

2010 ◽  
Vol 22 (3) ◽  
pp. 73-87 ◽  
Author(s):  
Nicholaos G. Demas ◽  
Robert A. Erck ◽  
George R. Fenske
Keyword(s):  
Boundary Lubrication ◽  
Cylinder Liner ◽  
Piston Skirt ◽  
Lubrication Conditions

The Effect of Trialkyl Phosphites and Other Oil Additives on the Boundary Lubrication of Ceramics: Friction of Silicon-Based Ceramics

1992 ◽  
Vol 114 (4) ◽  
pp. 653-658 ◽  
Author(s):  
Kei Demizu ◽  
Hiroyuki Ishigaki ◽  
Hideo Kakutani ◽  
Fukuzo Kobayashi
Keyword(s):  
Silicon Nitride ◽  
Boundary Lubrication ◽  
Carbon Chain ◽  
Hertzian Contact ◽  
Carbon Chain Length ◽  
Friction Coefficients ◽  
Oil Additives ◽  
Carbon Chains ◽  
Trialkyl Phosphites ◽  
Silicon Based

In order to examine the fundamental boundary lubrication properties of ceramics, reciprocating friction experiments of silicon based ceramics such as silicon carbide and silicon nitride were conducted with trialkyl phosphites and other oil additives. When ceramics were slid against ceramics, trialkyl phosphites with long carbon chains reduced the friction of silicon nitride markedly; the friction coefficients decreased with an increase in the carbon chain length. Other oil additives, however, did not greatly affect the friction. When ceramics were slid against metals, additives containing chlorine or sulfur increased friction of certain sliding couples. On the other hand, a trialkyl phosphite reduced friction and the friction coefficients increased with an increase in the maximum Hertzian contact pressure.

Thermal Influence on Torque Transfer of Wet Clutches in Limited Slip Differential Applications

2005 ◽  
Author(s):  
Pa¨r Marklund ◽  
Rikard Ma¨ki ◽  
Roland Larsson ◽  
Erik Ho¨glund ◽  
Michael M. Khonsari ◽  
...  
Keyword(s):  
Boundary Lubrication ◽  
High Load ◽  
Low Velocity ◽  
Thermal Influence ◽  
Lubrication Conditions

Wet clutches operating under low velocity and high load are studied with the aim of obtaining reliable models for the torque transfer during boundary lubrication conditions.

Influence of Water Absorption on Static Friction of Pure and Friction-Modified PA6 Polymers

2019 ◽  
Vol 799 ◽  
pp. 59-64
Author(s):  
Igor Velkavrh ◽  
Stefan Klien ◽  
Joel Voyer ◽  
Florian Ausserer ◽  
Alexander Diem
Keyword(s):  
Water Absorption ◽  
Static Friction ◽  
Polyamide 6 ◽  
Coated Steel ◽  
Friction Modifiers ◽  
Test Conditions ◽  
Influence Of Water ◽  
Steel Surfaces ◽  
Contact Pressures ◽  
Lubrication Conditions

In the present study, static coefficients of friction of pure and friction modified (FM) polyamide 6 (PA6) polymers against primer-coated steel surfaces were investigated under a series of nominal contact pressures and by considering the influences of water absorption by the polymer, temperature, counter-body surface roughness and lubrication conditions. Under the majority of the test conditions investigated, FM PA6 exhibited lower static friction than pure PA6. Under unlubricated conditions, this was due to the low adhesion of the FM PA6 provided by its friction modifying inclusions; while under lubricated conditions, a combination of softening due to water absorption and decreased adhesion provided by its friction modifiers enabled lower static friction, especially at medium and high contact pressures.

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