Silicon Nitride Boundary Lubrication: Effect of Sulfonate, Phenate and Salicylate Compounds

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.

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Study on Mechanism of Separate Type Boundary Lubrication in Low Frequency Torsional Vibration Tapping

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.424-425.111 ◽

2012 ◽

Vol 424-425 ◽

pp. 111-114

Author(s):

Feng Qi Han ◽

Zhi Zun Li ◽

De Yuan Zhang

Keyword(s):

Boundary Lubrication ◽

Torsional Vibration ◽

Low Frequency ◽

Cutting Fluid ◽

Separate Type ◽

Cutting Angle ◽

Lubrication Mode ◽

Type Boundary ◽

Lubrication Effect ◽

Key Parameter

Low frequency torsional vibration tapping is an effective method to solve the problem of tapping in difficult to cut materials. Tapping parameters affect tapping torque and service life of tap, and cutting angle is the key parameter. Experiments were conducted to study the lubrication mechanism and the influence of cutting angle on lubrication effect. Experimental results indicate that the separate type boundary lubrication mode greatly enhances the lubrication effect of cutting fluid and the lubrication effect decreases with the increase of cutting angle. To obtain good technological effect, the smaller cutting angle should be selected.

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Frictional anisotropy under boundary lubrication: Effect of surface texture

Wear ◽

10.1016/j.wear.2008.12.106 ◽

2009 ◽

Vol 267 (5-8) ◽

pp. 1214-1219 ◽

Cited By ~ 20

Author(s):

O.O. Ajayi ◽

R.A. Erck ◽

C. Lorenzo-Martin ◽

G.R. Fenske

Keyword(s):

Boundary Lubrication ◽

Surface Texture ◽

Lubrication Effect ◽

Effect Of Surface

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

Journal of Tribology ◽

10.1115/1.555366 ◽

1999 ◽

Vol 122 (1) ◽

pp. 348-353 ◽

Cited By ~ 1

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]

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Influence of Surface Roughness and Oil Ageing on Various Ceramic-Steel Contacts under Boundary Lubrication

Proceedings of the Institution of Mechanical Engineers Part J Journal of Engineering Tribology ◽

10.1243/pime_proc_1995_209_422_02 ◽

1995 ◽

Vol 209 (3) ◽

pp. 173-182 ◽

Cited By ~ 1

Author(s):

J Denape ◽

T Masri ◽

J-A Petit

Keyword(s):

Silicon Nitride ◽

Boundary Lubrication ◽

Friction And Wear ◽

Tetragonal Zirconia ◽

Degradation Process ◽

Wear Behaviour ◽

Fracture Mechanisms ◽

Initial Surface ◽

Tribological Behaviour ◽

Used Oil

The friction and wear behaviour of four structural ceramics (two aluminium oxides of different purity, a silicon nitride and a tetragonal zirconia polycrystal) have been investigated under boundary lubrication against a 100C6 hard steel (52100 steel). The effect of three initial surface roughnesses of the ceramics is studied. Lubrication is by a commercial oil used ‘as received’ (new oil) and ‘aged’ (used oil). Tests are performed on an alternating ‘pin-on-plate’ tribometer. The friction and wear responses are analysed in terms of three main parameters depending on the mechanical preparation mode of the ceramics surface: the roughness magnitude, the morphology of the asperities (sharps or blunts) and the mechanical strength of the asperities. The evolution of these parameters during sliding leads to significant changes of tribological behaviour and contact pressure. The friction and wear transitions result from changes of the lubrication mode where roughness and oil have a competitive action. The wear processes of the ceramic surfaces include fracture mechanisms of the asperities and/or polishing by the mechanochemical action of the lubricant and submicronic ceramic wear debris. The worn surfaces of steel exhibit either abrasion grooves or a continuous metallic layer covering the steel. A running-in effect is observed on both silicon nitride and zirconia but does not occur on aluminas. The stronger running-in effect is observed with used oil. The used oil can lead to a very smooth sliding surface on the ceramic and allows particularly low friction coefficients and steel wear, but only after a more severe initial degradation process ESCA analyses on steel reveal the occurrence of a reaction film generated through chemical reactions with the oil.

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