AVS 46th International Symposium
    Nanometer-scale Science and Technology Division Monday Sessions
       Session NS1-MoA

Paper NS1-MoA10
Sliding Transitions and Dissipation in Nanoscale Contacts

Monday, October 25, 1999, 5:00 pm, Room 612

Session: Nanoscale Tribology and Adhesion
Presenter: K.J. Wahl, Naval Research Laboratory
Authors: K.J. Wahl, Naval Research Laboratory
S.A.S. Asif, University of Florida
Correspondent: Click to Email
In order to investigate tribological processes at the nanometer scale, we need to better understand how model asperity contacts respond to shear and dissipate energy. In our experiments, we investigate the dynamic processes occurring during the transition from static to sliding contact, as well as during the formation and breaking of nanoscale adhesive contacts. Measurements are made using an atomic force microscope operated in shear modulation mode, where the sample position is modulated laterally with amplitudes as small as a few Å. Both amplitude and phase response of the contacts are monitored using a lock-in amplifier. In this work, we expand our technique to incorporate harmonic analysis of the response of the contact to lateral modulation. As a result, we are now able to distinguish between various types of dissipation including friction, microslip and damping. We demonstrate application of this technique to discriminate between static to sliding contacts as well as identify and quantify microslip in nanoscale contacts.