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For example, PTFE particles compounded in the plastic form a PTFE film over the mating surface, resulting in a reduction of friction and wear. MoS 2 compounded in nylon reduces wear, friction and stick-slip. Furthermore, it acts as a nucleating agent effecting in a very fine crystalline structure.
The friction coefficient is an empirical (experimentally measured) structural property that depends only on various aspects of the contacting materials, such as surface roughness. The coefficient of friction is not a function of mass or volume. For instance, a large aluminum block has the same coefficient of friction as a small aluminum block.
As can be estimated from weight loss and the density , the wear coefficient can also be expressed as: [2] K = 3 H W P L ρ {\displaystyle K={\frac {3HW}{PL\rho }}} As the standard method uses the total volume loss and the total sliding distance, there is a need to define the net steady-state wear coefficient:
Nylon is a family of synthetic ... fabric could also be itchy and tended to cling and sometimes spark as a result of static electrical charge built up by friction.
The coefficient of friction of plastics is usually measured against polished steel. [36] PTFE's coefficient of friction is 0.05 to 0.10, [27] which is the third-lowest of any known solid material (aluminium magnesium boride (BAM) being the lowest, with a coefficient of friction of 0.02; diamond-like carbon being second-lowest at 0.05).
Nylon 11 is seen to have increased dimensional stability in the presence of moisture due to its low concentration of amides. Nylon 11 experiences 0.2-0.5% length variation and 1.9% weight variation after 25 weeks of submersion in water in comparison to 2.2-2.7% elongation variation and 9.5% weight variation for Nylon 6. [2]
The coefficient of friction is determined by the ratio of the frictional force to the loading force on the pin. The pin on disc test has proved useful in providing a simple wear and friction test for low friction coatings such as diamond-like carbon coatings on valve train components in internal combustion engines.
Nikolai Pavlovich Petrov's method of lubrication analysis, which assumes a concentric shaft and bearing, was the first to explain the phenomenon of bearing friction.This method, which ultimately produces the equation known as Petrov's law (or Petroff's law), is useful because it defines groups of relevant dimensionless parameters, and predicts a fairly accurate coefficient of friction, even ...