The anti-scuffing performance of diamond nano-particles as an oil additive

This paper studied the anti-scuffing property of lubricating oil dispersed with diamond nano-particles as an oil additive. The lubricating oil which contains nano-diamond additive with various volumetric concentrations was used to evaluate the tribological performances and scuffing resistance demonstrated in the blocks-on-ring adapter operating at different speed and load conditions. The number of jumps in the friction coefficient, electrical contact resistance, and oil temperature were successively recorded in order to account for the number of jumps during the test and time length before appearing the first jump. The mean value of the experimental results evaluated in a global form for different operating conditions clearly shows the effects of additive concentration and the variable condition on the tribological performances including the scuffing resistance. 3 vol.% concentrations are the most favorable for reducing the mean friction coefficient and mean wear loss of applied operating conditions. Using this kind of nano-diamond additive in the base oil helps reduce the friction power. The friction power corresponding to 2 vol.% was the lowest of the four concentrations. An increase in the additive concentration helped delay the occurrence of the first scuffing. However, the increases in concentration reached saturation when the concentration was 3 vol.%. The bulk performances demonstrated in tribological parameters show that 3 vol.% of nano-diamond additive is the optimal choice of concentration for scuffing resistance in our tests.