Nanotribology, the study of friction, wear and lubrication at the nanoscale is an important area of research; however in practice due to the size scale, requires specifically designed tools to characterize nanoscale contacts. We have developed a TEM triboprobe incorporating an advanced nano-positioner with 3D programmable motion inside a transmission electron microscope (TEM) which allows us to selectively apply multiple reciprocating wear cycles to a nanoscale surface, and observe in real-time dynamical changes and the evolution of wear around a sliding nano-contact.
Nanoscale cyclic rubbing of an automotive aluminum-silicon alloy processed by focused ion beam (FIB) reveals dynamical surface fragmentation and the generation of nanoscale debris particles. The nanoparticles undergo complex motion as they interact with the sliding nano-contact. Over hundreds of reciprocating cycles, frictional heating leads to a phase separation of the Ga+ ions implanted by FIB forming liquid Ga nano-droplets and liquid bridges. The addition of nanoscale debris particles and liquid droplets dramatically changes the wear dynamics and transforms a 2-body sliding contact into a complex 4-body solid–liquid system exhibiting time-dependent, non-equilibrium kinetic behavior.
TEM nanotribology opens up new possibilities for the real-time quantification of cyclic friction, wear and dynamic solid–liquid nano-mechanics, which will have widespread applications in many areas of nano-science and nanotechnology.