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Appendix A

Friction Coefficients for some Common Materials and Materials Combinations

Table A.1: Friction Coefficients vs. Materials and Surface Conditions
Materials and Material Combinations
Surface Conditions, Lubricant
Frictional Coefficient
Static
– μstatic –
Kinetic (sliding)
– μsliding –
Aluminum Aluminum Clean and Dry 1.05 – 1.35 0.4
Aluminum Aluminum Lubricated and Greasy 0.3
Aluminum-bronze Steel Clean and Dry 0.45
Aluminum Mild Steel Clean and Dry 0.61 0.47
Aluminum Snow Wet 0 oC 0.4
Aluminum Snow Dry 0 oC 0.35
Brake material2) Cast iron Clean and Dry 0.4
Brake material2) Cast iron (wet) Clean and Dry 0.2
Brass Steel Clean and Dry 0.51 0.44
Brass Steel Grease 0.19
Brass Steel Castor oil 0.11
Brass Cast Iron Clean and Dry 0.3
Brass Ice Clean 0 oC 0.02
Brass Ice Clean -80 oC 0.15
Brick Wood Clean and Dry 0.6
Bronze Steel Grease 0.16
Bronze Cast Iron Clean and Dry 0.22
Bronze – sintered Steel Grease 0.13
Cadmium Cadmium Clean and Dry 0.5
Cadmium Cadmium Grease 0.05
Cadmium Chromium Clean and Dry 0.41
Cadmium Chromium Grease 0.34
Cadmium Mild Steel Clean and Dry 0.46
Cast Iron Cast Iron Clean and Dry 1.1 0.15
Cast Iron Cast Iron Clean and Dry 0.15
Cast Iron Cast Iron Grease 0.07
Cast Iron Oak Clean and Dry 0.49
Cast Iron Oak Grease 0.075
Cast iron Steel Clean and Dry 0.4
Cast iron Steel Clean and Dry 0.23
Cast iron Steel Grease 0.21 0.133
Car tire Asphalt Clean and Dry 0.72
Car tire Grass Clean and Dry 0.35
Carbon (hard) Carbon Clean and Dry 0.16
Carbon (hard) Carbon Grease 0.12 – 0.14
Carbon Steel Clean and Dry 0.14
Carbon Steel Grease 0.11 – 0.14
Chromium Chromium Clean and Dry 0.41
Chromium Chromium Grease 0.34
Copper-Lead alloy Steel Clean and Dry 0.22
Copper Copper Clean and Dry 1.6
Copper Copper Grease 0.08
Copper Cast Iron Clean and Dry 1.05 0.29
Copper Steel Clean and Dry 0.53 0.36
Copper Steel Grease 0.18
Copper Steel Oleic acid 0.18
Copper Glass Clean and Dry 0.68 0.53
Cotton Cotton Threads 0.3
Diamond Diamond Clean and Dry 0.1
Diamond Diamond Grease 0.05 – 0.1
Diamond Metals Clean and Dry 0.1 – 0.15
Diamond Metal Grease 0.1
Garnet Steel Clean and Dry 0.39
Glass Glass Clean and Dry 0.9 – 1.0 0.4
Glass Glass Grease 0.1 – 0.6 0.09 – 0.12
Glass Metal Clean and Dry 0.5 – 0.7
Glass Metal Grease 0.2 – 0.3
Glass Nickel Clean and Dry 0.78
Glass Nickel Grease 0.56
Graphite Steel Clean and Dry 0.1
Graphite Steel Grease 0.1
Graphite Graphite (in vacuum) Clean and Dry 0.5 – 0.8
Graphite Graphite Clean and Dry 0.1
Graphite Graphite Grease 0.1
Hemp rope Timber Clean and Dry 0.5
Horseshoe Rubber Clean and Dry 0.68
Horseshoe Concrete Clean and Dry 0.58
Ice Ice Clean 0 oC 0.1 0.02
Ice Ice Clean -12 oC 0.3 0.035
Ice Ice Clean -80 oC 0.5 0.09
Ice Wood Clean and Dry 0.05
Ice Steel Clean and Dry 0.03
Iron Iron Clean and Dry 1.0
Iron Iron Grease 0.15 – 0.20
Lead Cast Iron Clean and Dry 0.43
Leather Oak Parallel to grain 0.61 0.52
Leather Metal Clean and Dry 0.4
Leather Metal Grease 0.2
Leather Wood Clean and Dry 0.3 – 0.4
Leather Clean Metal Clean and Dry 0.6
Leather Cast Iron Clean and Dry 0.6 0.56
Leather fiber Cast iron Clean and Dry 0.31
Leather fiber Aluminum Clean and Dry 0.30
Magnesium Magnesium Clean and Dry 0.6
Magnesium Magnesium Grease 0.08
Magnesium Steel Clean and Dry 0.42
Magnesium Cast Iron Clean and Dry 0.25
Masonry Brick Clean and Dry 0.6 – 0.7
Mica Mica Freshly cleaved 1.0
Nickel Nickel Clean and Dry 0.7 – 1.1 0.53
Nickel Nickel Grease 0.28 0.12
Nickel Mild Steel Clean and Dry 0.64
Nickel Mild Steel Grease 0.178
Nylon Nylon Clean and Dry 0.15 – 0.25
Nylon Steel Clean and Dry 0.4
Nylon Snow Wet 0 oC 0.4
Nylon Snow Dry -10 oC 0.3
Oak Oak (parallel grain) Clean and Dry 0.62 0.48
Oak Oak (cross grain) Clean and Dry 0.54 0.32
Oak Oak (cross grain) Grease 0.072
Paper Cast Iron Clean and Dry 0.20
Phosphor-bronze Steel Clean and Dry 0.35
Platinum Platinum Clean and Dry 1.2
Platinum Platinum Grease 0.25
Plexiglas Plexiglas Clean and Dry 0.8
Plexiglas Plexiglas Grease 0.8
Plexiglas Steel Clean and Dry 0.4 – 0.5
Plexiglas Steel Grease 0.4 – 0.5
Polystyrene Polystyrene Clean and Dry 0.5
Polystyrene Polystyrene Grease 0.5
Polystyrene Steel Clean and Dry 0.3 – 0.35
Polystyrene Steel Grease 0.3 – 0.35
Polyethylene Polytehylene Clean and Dry 0.2
Polyethylene Steel Clean and Dry 0.2
Polyethylene Steel Grease 0.2
Rubber Rubber Clean and Dry 1.16
Rubber Cardboard Clean and Dry 0.5 – 0.8
Rubber Dry Asphalt Clean and Dry 0.9 0.5 – 0.8
Rubber Wet Asphalt Clean and Dry 0.25 – 0.75
Rubber Dry Concrete Clean and Dry 0.6 – 0.85
Rubber Wet Concrete Clean and Dry 0.45 – 0.75
Silk Silk Clean 0.25
Silver Silver Clean and Dry 1.4
Silver Silver Grease 0.55
Sapphire Sapphire Clean and Dry 0.2
Sapphire Sapphire Grease 0.2
Silver Silver Clean and Dry 1.4
Silver Silver Grease 0.55
Skin Metals Clean and Dry 0.8 – 1.0
Steel Steel Clean and Dry 0.5 – 0.8 0.42
Steel Steel Grease 0.16
Steel Steel Castor oil 0.15 0.081
Steel Steel Stearic Acid 0.15
Steel Steel Light mineral oil 0.23
Steel Steel Lard 0.11 0.084
Steel Steel Graphite 0.058
Steel Graphite Clean and Dry 0.21
Straw Fiber Cast Iron Clean and Dry 0.26
Straw Fiber Aluminum Clean and Dry 0.27
Tarred fiber Cast Iron Clean and Dry 0.15
Tarred fiber Aluminum Clean and Dry 0.18
Polytetrafluoroethylene (PTFE) (Teflon) Polytetrafluoroethylene (PTFE) Clean and Dry 0.04 0.04
Polytetrafluoroethylene (PTFE) Polytetrafluoroethylene (PTFE) Grease 0.04
Polytetrafluoroethylene (PTFE) Steel Clean and Dry 0.05 – 0.2
Polytetrafluoroethylene (PTFE) Snow Wet 0 oC 0.05
Polytetrafluoroethylene (PTFE) Snow Dry 0 oC 0.02
Tungsten Carbide Steel Clean and Dry 0.4 – 0.6
Tungsten Carbide Steel Grease 0.1 – 0.2
Tungsten Carbide Tungsten Carbide Clean and Dry 0.2 – 0.25
Tungsten Carbide Tungsten Carbide Grease 0.12
Tungsten Carbide Copper Clean and Dry 0.35
Tungsten Carbide Iron Clean and Dry 0.8
Tin Cast Iron Clean and Dry 0.32
Tire, dry Road, dry Clean and Dry 1
Tire, wet Road, wet Clean and Dry 0.2
Wax, ski Snow Wet 0 oC 0.1
Wax, ski Snow Dry 0 oC 0.04
Wax, ski Snow Dry -10 oC 0.2
Wood Clean Wood Clean and Dry 0.25 – 0.5
Wood Wet Wood Clean and Dry 0.2
Wood Clean Metal Clean and Dry 0.2 – 0.6
Wood Wet Metals Clean and Dry 0.2
Wood Stone Clean and Dry 0.2 – 0.4
Wood Concrete Clean and Dry 0.62
Wood Brick Clean and Dry 0.6
Wood – waxed Wet snow Clean and Dry 0.14 0.1
Wood – waxed Dry snow Clean and Dry 0.04
Zinc Cast Iron Clean and Dry 0.85 0.21
Zinc Zinc Clean and Dry 0.6
Zinc Zinc Grease 0.04

References

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