Does surface hardness equate to scratch resistance?
10-28-2015, 09:00 AM
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Burning Brakes
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Does surface hardness equate to scratch resistance?
Glass is a very hard surface and yet its easily scratched; but it’s surface roughness that is the major factor; not hardness, the rougher the surface, the higher the coefficient of friction (or resistance) the more the surface is prone to scratches when a towel or some other object is dragged across its surface.
Both glass and paint surfaces contain microscopic peaks and valleys, much like the profile of a mountain range. These irregularities are known as capillary structures; there may be millions of these defects per square inch. Such a surface has a high coefficient of friction and is relatively easy to scratch
When a coating is correctly applied to this type of surface it fills in the capillary structures and the surface takes on properties that are virtually identical to that of uniformly smooth glass, with a uniform thickness will a low coefficient of kinetic friction by filling of the capillary structures with micro particles producing a very smooth surface
Surface friction
Friction force [: is the force exerted by a surface when an object moves across a surface].
Coefficient of kinetic friction [:is a measure of resistance of thin films that are nominally uniform in thickness]
Coefficient of friction isn't a rigidly defined physical quantity, it's an approximation; if you approximate the force vs. friction as being directly proportional, that proportionality constant is the coefficient of friction, i.e. materials with extreme coefficients of friction, Teflon (low) and rubber (high) are commonly available examples of each.
Glass is a very hard surface and yet its easily scratched; but it’s surface roughness that is the major factor; not hardness, the rougher the surface, the higher the coefficient of friction (or resistance) the more the surface is prone to scratches when a towel or some other object is dragged across its surface.
Both glass and paint surfaces contain microscopic peaks and valleys, much like the profile of a mountain range. These irregularities are known as capillary structures; there may be millions of these defects per square inch. Such a surface has a high coefficient of friction and is relatively easy to scratch
When a coating is correctly applied to this type of surface it fills in the capillary structures and the surface takes on properties that are virtually identical to that of uniformly smooth glass, with a uniform thickness will a low coefficient of kinetic friction by filling of the capillary structures with micro particles producing a very smooth surface
Surface friction
Friction force [: is the force exerted by a surface when an object moves across a surface].
Coefficient of kinetic friction [:is a measure of resistance of thin films that are nominally uniform in thickness]
Coefficient of friction isn't a rigidly defined physical quantity, it's an approximation; if you approximate the force vs. friction as being directly proportional, that proportionality constant is the coefficient of friction, i.e. materials with extreme coefficients of friction, Teflon (low) and rubber (high) are commonly available examples of each.
The Science behind Coatings - http://togwt1980.blogspot.co.uk/2015...d-coatings.html
