Tribological Behaviour of Neem Oil with and without Graphene Nanoplatelets Using Four-Ball Tester

Figure 11

Illustration of formation of thin-film between balls just before the weld: (a) 0.25 wt.% GNPs-NO, (b) 0.50% GNPs-NO, and (c) 1.0% GNPs-NO.

(a)

(b)

(c)