Physics > Friction Coefficients
The table below shows a comprehensive list of frictional coefficients for common materials.
Frictional forced can be expressed as:
Fr = μN
Where:
- Fr is the resistive force of friction
- μ is the coefficient of friction for the two surfaces (Greek letter "mu")
- N is the normal or perpendicular force pushing the two objects together
- μN is μ times N
Materials and Material Combinations |
Static Frictional Coefficient - μ s |
Clean and Dry Surfaces |
Lubricated and Greasy Surfaces |
Aluminium |
Aluminium |
1.05 - 1.35 |
0.3 |
Aluminium-bronze |
Steel |
0.45 |
|
Aluminium |
Mild Steel |
0.61 |
|
Brake material |
Cast iron |
0.4 |
|
Brake material |
Cast iron (wet) |
0.2 |
|
Brass |
Steel |
0.35 |
0.19 |
Brass |
Cast Iron |
0.31) |
|
Brick |
Wood |
0.6 |
|
Bronze |
Steel |
|
0.16 |
Bronze |
Cast Iron |
0.221) |
|
Bronze - sintered |
Steel |
|
0.13 |
Cadmium |
Cadmium |
0.5 |
0.05 |
Cadmium |
Chromium |
0.41 |
0.34 |
Cadmium |
Mild Steel |
0.461) |
|
Cast Iron |
Cast Iron |
1.1, 0.151) |
0.071) |
Cast Iron |
Oak |
0.491) |
0.075 1 |
Cast iron |
Mild Steel |
0.4, 0.231) |
0.21, 0.1331) |
Carbon (hard) |
Carbon |
0.16 |
0.12 - 0.14 |
Carbon |
Steel |
0.14 |
0.11 - 0.14 |
Chromium |
Chromium |
0.41 |
0.34 |
Copper-Lead alloy |
Steel |
0.22 |
|
Copper |
Copper |
1 |
0.08 |
Copper |
Cast Iron |
1.05, 0.291) |
|
Copper |
Mild Steel |
0.53, 0.361) |
0.181) |
Diamond |
Diamond |
0.1 |
0.05 - 0.1 |
Diamond |
Metal |
0.1 - 0.15 |
0.1 |
Glass |
Glass |
0.9 - 1.0, 0.41) |
0.1 - 0.6, 0.09 - 0.121) |
Glass |
Metal |
0.5 - 0.7 |
0.2 - 0.3 |
Glass |
Nickel |
0.78 |
0.56 |
Graphite |
Steel |
0.1 |
0.1 |
Graphite |
Graphite (in vacuum) |
0.5 - 0.8 |
|
Graphite |
Graphite |
0.1 |
0.1 |
Iron |
Iron |
1.0 |
0.15 - 0.20 |
Lead |
Cast Iron |
0.431) |
|
Leather |
Oak |
0.61, 052 1 |
|
Leather |
Metal |
0.4 |
0.2 |
Leather |
Wood |
0.3 - 0.4 |
|
Leather |
Clean Metal |
0.6 |
|
Magnesium |
Magnesium |
0.6 |
0.08 |
Nickel |
Nickel |
0.7 - 1.1, 0.531) |
0.28, 0.121) |
Nickel |
Mild Steel |
0.641) |
0.1781) |
Nylon |
Nylon |
0.15 - 0.25 |
|
Oak |
Oak (parallel grain) |
0.62, 0.481) |
|
Oak |
Oak (cross grain) |
0.54, 0.32 1 |
0.072 1 |
Phosphor-bronze |
Steel |
0.35 |
|
Platinum |
Platinum |
1.2 |
0.25 |
Plexiglas |
Plexiglas |
0.8 |
0.8 |
Plexiglas |
Steel |
0.4-0.5 |
0.4 - 0.5 |
Polystyrene |
Polystyrene |
0.5 |
0.5 |
Polystyrene |
Steel |
0.3-0.35 |
0.3 - 0.35 |
Polythene |
Steel |
0.2 |
0.2 |
Polystyrene |
Polystyrene |
0.5 |
0.5 |
Rubber |
Dry Asphalt |
0.5 - 0.81) |
|
Rubber |
Wet Asphalt |
0.25 - 0.751) |
|
Rubber |
Dry Concrete |
0.6 - 0.851) |
|
Rubber |
Wet Concrete |
0.45 - 0.751) |
|
Silver |
Silver |
1.4 |
0.55 |
Sapphire |
Sapphire |
0.2 |
0.2 |
Silver |
Silver |
1.4 |
0.55 |
Steel |
Steel |
0.8 |
0.16 |
Teflon |
Teflon |
0.04 |
0.04, 0.041) |
Teflon |
Steel |
0.04 |
0.04 |
Tungsten Carbide |
Steel |
0.4-0.6 |
0.1 - 0.2 |
Tungsten Carbide |
Tungsten Carbide |
0.2 - 0.25 |
0.12 |
Tungsten Carbide |
Copper |
0.35 |
|
Tungsten Carbide |
Iron |
0.8 |
|
Teflon |
Teflon |
0.04 |
0.04 |
Tin |
Cast Iron |
0.321) |
|
Wood |
Clean Wood |
0.25 - 0.5 |
|
Wood |
Wet Wood |
0.2 |
|
Wood |
Clean Metal |
0.2 - 0.6 |
|
Wood |
Wet Metals |
0.2 |
|
Wood |
Concrete |
0.62 |
|
Wood |
Brick |
0.6 |
|
|
Wet snow |
0.14, 0.11) |
|
Wood - waxed |
Dry snow |
0.041) |
|
Zinc |
Cast Iron |
0.85, 0.211) |
|
Zinc |
Zinc |
0.6 |
0.04 |