Effect of Contact Load on Friction

A number of investigations have been made into the influence of contact load on the frictional properties of molybdenum disulphide. Puchkov and Pashkov used a technique which they claimed to differentiate between shear stress and surface friction. They studied the effect of varying compressive stress on the resistance to 

The form of this relationship inorganic compounds by Bridgeman 

Akaoka and Nitanai ° carried out similar studies, but used a thicker film and obtained much lower shear strengths. They found a non-linear relationship 

This exactly follows the relationship found experimentally by several investigators, and provides strong support for the generally-accepted view that the low friction of molybdenum disulphide is due to easy shear between lamellae. 

The discussion so far has considered only the problem of slip taking place between adjacent lamellae in a single crystal, or in some other form in which the interaction between lamellae simulates their behaviour in a single crystal. The same arguments will not necessarily apply to the practical case of sliding which takes place between two components lubricated with molybdenum disulphide. 

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