Preparation and Tribological Properties of Dual-Coated TiO₂ Nanoparticles as Water-Based Lubricant Additives

Figure 9

SEM and EDS analysis of worn surface of steel ball after four-ball test lubricated by the water-added 1.6 vt.% TiO₂ nanoparticles. (a) Without ultrasonic washing; (b) with ultrasonic washing for 2 minutes; (c) with ultrasonic washing for 5 minutes.

(a)

(b)

(c)