Physics @ Berkeley
Events in Physics
Title: Slip Sliding Away: Atomic-scale Processes That Govern Friction And Wear    (Colloquia)
Start Date: 04/28/2014
Time: 4:15 pm
Location: 1 LeConte Hall
Speaker: Robert Carpick
Affiliation: Professor and Chair of Physics, University of Pennsylvania
Contact Person: Sarah Wittmer   (510) 644-7155

I will discuss recent atomic force microscopy studies of nanoscale single asperity contacts. First, the frictional behavior of truly 2-dimensional materials will be discussed. For contacts to graphene and other 2-D materials, friction depends strongly on the number of 2-D layers. An even stronger effect occurs when graphene is fluorinated, an effect which can be interpreted in the context of the classical Prandti-Tomlinson model of stick-slip friction. I will then discuss the characterization of wear with unprecedented resolution using in-situ tests inside of a transmission electron microscope. For silicon slid against diamond, the shape evolution and volume loss due to wear closely fit a kinetic model based on stress-assisted bonding mechanisms. This allows new insights to be gained about the kinetics of atomic-scale wear.