Micro/nano-wear studies on epoxy/silica nanocomposites

We proposed a new method for quantifying the micro/nano-scale wear volume (i.e., volume of wear loss) to characterize the wear-resistance of nanocomposites. Effects of wear load, pass (a pattern of scan cycles), and nanoparticle content on the wear behavior of silica nanoparticle-reinforced composites (EP/SiO2) were studied. The multiple nano-scratch patterning technique was carried out for the wear test. Images of sample surface, before/after the test, obtained using in situ scanning probe microscopy (SPM) were used to calculate the wear volume. Our results indicate that the wear mechanism transits from a plastic-deformation dominated mode to a fatigue-wear dominated mode with increased wear load and pass. The threshold at which transition occurs increases with the nanoparticle content, and correlates with improvement in wear resistance of nanocomposites. This transition threshold can be a different metric, rather than using the conventional mechanical properties (e.g., surface hardness and stiffness), to characterize the wear resistance of materials such that wear load and pass is taken into account.