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Friction Coefficient Tables in Air and Vacuum
03.01.2022
Table of Contents
Friction coefficient tables for solid lubricants, metals, plastics and anti-friction materials
Friction coefficient tables for various material pairs in atmosphere and vacuum are provided below. The data was collected from various sources [1,2,3]. See the definition of friction coefficient.
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 table
Materials | Static friction coefficient | |
---|---|---|
Steel | Aluminium Bros | 0.45 |
Steel | Brass | 0.35 |
Steel(Mild) | Brass | 0.51 |
Steel | Cast Iron | 0.4 |
Steel | Copper Lead Alloy | 0.22 |
Steel (Hard) | Graphite | 0.21 |
Steel | Graphite | 0.1 |
Steel (Mild) | Lead | 0.95 |
Steel | Phos Bros | 0.35 |
Steel(Hard) | Polythened | 0.2 |
Steel(Hard) | Polystyrene | 0.3-0.35 |
Steel (Mild) | Steel (Mild) | 0.74 |
Steel(Hard) | Steel (Hard) | 0.78 |
Steel | Zinc (Plated on steel) | 0.5 |
Steel | Tungsten Carbide | 0.4 – 0.6 |
Steel | Teflon | 0.04 |
Steel | Polythene | 0.2 |
Steel | Polystyrene | 0.3-0.35 |
Steel | Plexiglas | 0.4 – 0.5 |
Steel | Hard Carbon | 0.14 |
Steel | Graphite | 0.1 |
Steel | Copper-Lead Alloy | 0.22 |
Steel (Mild) | Copper | 0.53 |
Steel (Mild) | Aluminum | 0.61 |
Friction Coefficient of Wood, Leather, and Stone
Material Pair | Static COF | Dynamic COF |
---|---|---|
Hardwood on hardwood | — | 0.129 |
Oak on oak, parallel to the grain | 0.62 | 0.48 |
Oak on oak, perpendicular to the grain | 0.54 | 0.32 |
Cast iron on oak | — | 0.49 |
Brick on wood | 0.6 | — |
Clean wood on metals | 0.2–0.6 | — |
Leather on iron | — | 0.25 |
Leather on oak, parallel to the grain | 0.61 | 0.52 |
Leather on cast iron | — | 0.56 |
Leather on metal | 0.6 | — |
Sliding Friction Coefficient Table for Selected Ceramic Materials (Room Temperature in Air)
Ceramic | Counterface | μ |
---|---|---|
Al2O3 | Al2O3 | 0.33–0.50 |
Al2O3 | Al2O3 | 0.20–0.9 |
α-Al2O3 | α-Al2O3 | 0.38–0.42 |
Al2O3 | Al2O3–SiC composite | 0.53 |
Al2O3–SiC composite | Al2O3–SiC composite | 0.64–0.84 |
B4C | B4C | 0.53 |
SiC | SiC | 0.52 |
SiC | Si3N4 | 0.53–0.71 |
WC | WC | 0.34 |
Si3N4 | Si3N4 | 0.42–0.82 |
Ice friction coefficient
Depending on pressure, temperature, and the conditions of formation, ice can take on any of at least eight allotropic forms, the largest number for any known substance. These changes impact the ice friction coefficient behavior, as shown in the figure below.
Material | μs (0°C) | μs (-5°C) | μs (-10°C) |
---|---|---|---|
Ski lacquer (pigmented nitrocellulose plasticized with phthalate) | 0.05 | 0.11 | 0.43 |
Paraffi n wax | 0.04 | 0.27 | 0.37 |
Norwegian wax (sulfur-free, bituminous wax) | 0.045 | 0.1 | 0.2 |
Swiss wax (highly refi ned, bituminous, hydrocarbon wax with 1.5% Al powder) | 0.05 | 0.1 | 0.2 |
Polytetrafluoroethylene (PTFE) | 0.04 | 0.05 | 0.55 |
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 Material | Flat Material | μinitial | μsteady-state |
---|---|---|---|
Cu | Cu | 1.2 | 0.6 |
Cu | Glass | 1.2 | 0.65 |
Fe | Fe | 0.7 | 0.65 |
Fe | Glass | 0.8 | 0.85 |
Steel | Steel | 0.6 | 0.55 |
Steel | Glass | 1.3 | 0.62 |
CuO | CuO | 0.7 | 0.65 |
Cu2O | Cu2O | 0.65 | 0.62 |
Fe2O3 | Fe2O3 | 0.62 | 0.6 |
Fe3O4 | Fe3O4 | 0.3 | – |
Friction coefficient table in fretting regime as a function of humidity
Metal | μ steady-state | ||||||
---|---|---|---|---|---|---|---|
0–2% RH | 10–12% RH | 49–50% RH | |||||
Fe | 0.45 | 0.4 | 0.25 | ||||
Ni | 0.42 | — | 0.19 | ||||
Ti | 0.35 | 0.4 | 0.28 | ||||
Cr | 0.25 | — | 0.22 |
References
- [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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