METEORITE

With the fast-growing development of electric mobility, there is a pressing need to improve the efficiency of tribological systems subjected to electrical stresses. Not to mention the fact that this development is associated with increasingly harsh environments: higher frictional speeds, higher voltages, higher temperatures. Similar challenges are also observed in wind turbine motors. More generally, the growing development of high power-density electrical systems (photovoltaic panels in solar plants, on-board electronics, power electronics, etc.) also requires the comprehensive understanding of electro-mechanical contacts under severe conditions (temperature cycling, intermittent contacts, arcing, etc.) METEORITE project is a highly multidisciplinary project at the crossroads of tribology, physical-chemistry and electronic transport in materials. It focuses on the development of dedicated instruments (with their associated methodologies) that combine in-operando electrical and tribological multi-scale characterizations. Electrical methods will be used either to monitor or to stress sliding interfaces placed in severe conditions. MoS2-based lubricants (both liquid and solid) will be used as application cases to illustrate the feasibility and the performance of the approach. Electrical measurements are currently under-exploited for the comprehensive understanding of the physical-chemistry of mechanical contacts. By coupling in-situ electrical, tribological and physical-chemical characterizations, this project proposes to enrich our understanding of contacts under severe conditions: mechanical and/or electrical cycling, high-temperature contact, etc. This coupling will be used either to better monitor the contact, or to stress it. The "Instrumentation" part will lie on the development of instruments that are already unique worldwide: at SIMaP, tribological measurements will be implemented on an in-situ SEM electrical-nanoindentation device; at LTDS, the environment controlled analytical tribometer will be coupled with advanced electrical measurements. These tools will complement each other in terms of spatial scale, mechanical sensitivity and in-situ characterization techniques. The "Characterization" part will focus on steels with MoS2-based lubricants (liquid or solid). The aim will be to better describe the kinetics of the nucleation/growth/microstructural processes of tribofilms, in relation to surface chemistry and tribological performance. The effect of electrical stresses on tribofilm growth and aging will also be studied. METEORITE combines two complementary areas of expertise: the tribological and physico-chemical study of contacts (LTDS) and the coupling of electrical and mechanical behaviors at small scales (SIMaP).