Surface forces apparatus in nanotribology

Abstract

The Surface Forces Apparatus (SFA) has proven to be an excellent tool for research in nanotribology. It allows the study of single or multiple asperity contacts lubricated or not. The normal load, the contact area and the 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 space of parameters 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.