Friction Coefficient Tables in Air and Vacuum

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Tribology Wikipedia > Friction Coefficient Tables in Air and Vacuum

Friction coefficient table of solid lubricants, metals, plastics and anti-friction materials

Friction coefficient table for various material pairs in atmosphere and vacuum (see the definition of friction coefficient) is shown below. The data was collected from various sources [1,2,3].

Material Combination Friction coefficient in air Friction coefficient in vacuum
Fe-Fe 0.3 1.9
Fe-Mg 1 0.6
Fe-Cd 1.5 0.4
Fe-Pb 0.9 0.4
Stainless Steel -Stainless Steel 0.5 2.9
Stainless Steel – Cu 0.3
Stainless Steel-Al 0.4 0.3
Stainless Steel-Mo 0.8
Stainless Steel-Ni 0.8
Stainless Steel-Teflon 0.2
Stainless Steel-Si 0.2
Stainless Steel-Ge 0.2
Stainless Steel-Glass 0.5
Chromium Steel – Chromium Steel 0.5 0.5
Cu-Cu 0.5-1.0 4.8-21.0
Cu-Ni 0.6 1.5-2.0
Al-Al 0.8 1.6-2.2
Al-Ni 2.4
Al-Cu 1.5
Al-Ag 2.2
Brass-Brass 0.4 0.7
Ni-Ni 4.9
Ag-Ag 3.9
Cr-Cr 0.6 3
Au-Au 0.6 4.5
Zn-Zn 1 3
Zr-Zr 1.5
Chromium Steel – MoS2 (vacuum deposition) 0.06
Chromium Steel – MoS2 (friction deposition) 0.06
Cu-MoS2 0.2 0.07
Brass-Steel 0.35
Tire – Asphalt 0.72
Tire – Grass 0.35
Diamond – Diamond 0.1
Glass – Glass 0.9-1.0
Graphite – Steel 0.1
Graphite – Graphite 0.1 0.5-0.8
Ice – Ice 0.02-0.09
Ice – Steel 0.03
Wood – Wood >0.2
Polytetrafluoroethylene – Polytetrafluoroethylene 0.04

Steel friction coefficient

Materials Static friction coefficient
SteelAluminium Bros0.45
SteelBrass0.35
Steel(Mild)Brass0.51
SteelCast Iron0.4
SteelCopper Lead Alloy0.22
Steel (Hard)Graphite0.21
SteelGraphite0.1
Steel (Mild)Lead0.95
SteelPhos Bros0.35
Steel(Hard)Polythened0.2
Steel(Hard)Polystyrene0.3-0.35
Steel (Mild)Steel (Mild)0.74
Steel(Hard)Steel (Hard)0.78
SteelZinc (Plated on steel)0.5
SteelTungsten Carbide0.4 - 0.6
SteelTeflon0.04
SteelPolythene0.2
SteelPolystyrene0.3-0.35
SteelPlexiglas0.4 - 0.5
SteelHard Carbon0.14
SteelGraphite0.1
SteelCopper-Lead Alloy0.22
Steel (Mild)Copper0.53
Steel (Mild)Aluminum0.61

Friction coefficient table for materials in fretting regime

In fretting, friction coefficients are different for the same pairs of materials due to changes in friction mechanisms. These tables include some data for commonly used materials.

Ball MaterialFlat Materialμinitialμsteady-state
CuCu1.20.6
CuGlass1.20.65
FeFe0.70.65
FeGlass0.80.85
SteelSteel0.60.55
SteelGlass1.30.62
CuOCuO0.70.65
Cu2OCu2O0.650.62
Fe2O3Fe2O30.620.6
Fe3O4Fe3O40.3No

Friction coefficient table in fretting regime as a function of humidity

Metal μsteady-state     
0–2% RH10–12% RH49–50% RH
Fe0.450.40.25
Ni0.420.19
Ti0.350.40.28
Cr0.250.22

[1]. Mechanics and Physics of Precise Vacuum Mechanisms, E.A. Deulin, V.P. Mikhailov, Yu.V. Panfilov, R.A. Nevshupa.

[2]. http://www.engineeringtoolbox.com/friction-coefficients-d_778.html.

[3]. Friction Science and Technology: From Concepts to Applications, Peter J. Blau, 2005

 

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