Nanoscale friction and wear maps

Abstract

Friction and wear are part and parcel of all walks of life, and for interfaces that are in close or near contact, tribology and mechanics are supremely important. They can critically influence the efficient functioning of devices and components. Nanoscale friction force follows a complex nonlinear dependence on multiple, often interdependent, interfacial and material properties. Various studies indicate that nanoscale devices may behave in ways that cannot be predicted from their larger counterparts. Nanoscale friction and wear mapping can help identify some 'sweet spots' that would give ultralow friction and near-zero wear. Mapping nanoscale friction and wear as a function of operating conditions and interface properties is a valuable tool and has the potential to impact the very way in which we design and select materials for nanotechnology applications.

Mechanisms of anisotropic friction in nanotwinned Cu revealed by atomistic simulations

“…Friction and wear, as common reasons for energy and material loss, are of both scientific and technological importance for nanostructured materials, given the minute volume of such structures [1][2][3][4]. With the emergence of advanced nanostructured materials containing hierarchic microstructures, understanding the mechanisms governing their frictional behavior on the nanoscale becomes challenging.…”

Rheological and tribological characterization of novel modified graphene/oil‐based nanofluids using force microscopy

“…In Figure 3, a contour map of the friction forces obtained at various sliding speeds and various normal loads is given for the base oil nanofluid with added 0.1 and 0.5% silane‐modified GNS by mass, respectively. According to Tambe and Bhushan, if the contour lines are in the form of horizontal lines, the friction force does not depend on the sliding speed (Tambe & Bhushan, 2008). If the contour lines are vertical, the friction force does not depend on the normal load.…”

“…If the contour lines are vertical, the friction force does not depend on the normal load. Contour lines with positive or negative slope observed in these graphs arise due to stick–slip interactions or meniscus bridges of liquid films at the sliding interface (Gnecco et al, 2004; Riedo, Gnecco, Bennewitz, Meyer, & Brune, 2003; Tambe & Bhushan, 2005b; Tambe & Bhushan, 2008). As seen in Figure 3, the dominant friction mechanism for SilA‐GNS and SilB‐GNS, which contain the amine functional group, was the atomic scale stick–slip behavior at both 0.1% and 0.5% concentration and low sliding speeds.…”

Wear

“…Various regimes of mechanical (plastically dominated) and chemical (oxidational) wear for a particular sliding material pair are observed on a single wear-regime map (or wear-mode map or wear-mechanism map) plotted on axes of normalized pressure and normalized sliding velocity on the macroscale and nanoscale (Tambe and Bhushan, 2008). No single wear mechanism operates over a wide range of conditions.…”