In-situ SEM Microrobotics for Versatile Force/Deformation Characterization: Application to Third-Body MoS2 Wear Particles

Abstract Purpose: This article explores the challenges and solutions in the physical characterization of materials at the microscale using robots, with a specific focus on manipulating and characterizing micrometer-sized particles with different and complex 3D shapes and internal sub-micrometer structures. Particles considered as case-study in this paper are made of Molybdenum diSulfide (MoS2) based materials generated within the contact interface during friction. These particles are of high interest for friction reduction and energy saving, but they are dispersed randomly inside the contact and have complex sub-micrometer structures. Methods: Characterization demands precise manipulation techniques in an in-situ Scanning Electron Microscope(SEM) environment. To address these challenges, existing commercial micro and nanomanipulation tools are integrated within a vacuum SEM chamber, and robotics strategies are investigated to enable the whole process from particle preparation, and manipulation setup definition, to effective MoS2 particle characterization all in-situ SEM. Results: A set of several complementary experimental investigations are done and involve force measurement and deformation estimation studies, leading to the first qualitative results on MoS2 based particles directly from the friction track. The work contributes to advancements in both microscale manipulation and characterization. It also has implications for lubrication research.