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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