Investigation on microtribological behavior of thin films using friction force microscopy

A purpose-built atomic force and friction force microscope (AFM/FFM) was employed to study micro friction and wear behavior of thin films of Langmiur–Blodgett (L–B), gold (Au), polytetrafluoroethylene (PTFE), silicon nitride (Si3N4) and PTFE/Si3N4 multi-layers prepared by different deposition techniques. The results show that the L–B film has a low friction coefficient but can be worn easily under a light load less than 20 nN; Au film and silicon wafer has a higher friction coefficient than that of L–B film and can be worn under a higher load of approximately 50 nN; the PTFE/Si3N4 multilayer has a lower friction coefficient than that of Si3N4 and has a higher micro wear resistance than that of PTFE. The friction force of the PTFE/Si3N4 multilayer is linear with the load at the nanometer scale. The worn track is formed in PTFE film and PTFE/Si3N4 multilayers when the load is greater than 70 nN.