“Surface Forces Apparatus in Nanotribology”

The Surface Forces Apparatus (SFA) has proven to be an excellent tool for studies in nanotribology. The normal load, contact area, and sliding velocity between the surfaces can be controlled and unambiguously measured with higher accuracy than in any conventional tribometer. Furthermore, an image of the surfaces in contact can be obtained as the surfaces are slid, allowing the monitoring of the real size and shape of the contact area and the distance or film thickness profile between the surfaces when atomically smooth surfaces are used. It is relatively simple to perform a comprehensive exploration of the full parameter space to determine the important variables in the frictional behavior of the system. In this chapter, the principles of operation and some experimental details of the Surface Forces Apparatus nanotribometer are described.