In Situ Friction Tests in a Transmission Electron Microscope

Abstract

Post mortem characterization techniques are essential for the understanding of the lubrication mechanisms of complex tribological systems. The information obtained using these techniques can be used to propose hypothesis of mechanisms that have then to be definitively validated by probing the interfacial material in real time during the friction test. To go further in the understanding of the action modes of some tribological systems, it is important to set up an analytical methodology using in situ experimental techniques in order to (i) probe directly the behavior of the interfacial material in the contact zone and (ii) dissociate, for a better understanding, the different components of the tribological stress (pressure and shear). There are several techniques that combine mechanical stress and in situ analysis (Raman tribology, Infra-Red tribology, EXAFS under pressure …). However, the most interesting techniques are certainly those that permit a visualization of the contact area in real time area during the friction test, down to a nanometer scale. The objective of this chapter is to present through some examples the potential of in situ friction tests done inside a transmission electron microscope.