Centrale Lyon

**Context and main objective**:
In our society, the fast-growing **development of electric mobility and power sourcing** poses new challenges for the improvement of energy efficiency. Among others, many **efficiency and durability limitations** in electric motors or generators (e.g. used in electric vehicles or wind turbines) are now attributed to **tribological issues** at sliding interfaces. At these contact points, friction forces (which result in energy losses) and wear (which leads to material losses and damage) are governed by the physical and chemical properties of the interfaces.

**A project at the crossroads of scientific disciplines**:
This project lies at the crossroads of different scientific disciplines (**tribology and electrical **characterization**), and bridges the gap between fundamental and applied research on interface physical-chemistry.
- The **electrical characterization of interfaces** is a discipline found in various scientific fields: microelectronics, nanotechnologies, power systems (such as fuel cells and batteries), corrosion monitoring and tribology. In the latter field, however, only basic measurements are typically conducted, leaving the full potential of such characterizations largely underutilized: quasi-static current-voltage characteristics, impedance spectroscopy

The present project will merge these two scientific disciplines, through the experimental coupling of tribological and electrical characterizations of interfaces. The electrical approach will be used to either characterize and stress the tribological interfaces.

In terms of lubrification, focus will be made on MoS2-based lubricants, either with solid lubricant films deposited by magnetron sputtering or with liquid lubricants containing chemical precursors able to generate MoS2 nano-sheets.

**Description of the research activities**:
This PhD work will essentially rely on **experimental tasks**, even though the processing and interpretation of experimental data will be essential. Experiments will be performed on **tribometers equipped with electrical measurements**.

The PhD student will have in charge the experiments able to answer the following scientific questions:

- ** Electrical monitoring of a tribofilm**: Are the electrical measures sensitive to the physical-chemistry of the tribofilm? Can they be used to monitor its nucleation and growth?
- ** Effect of electrical stressing**: What is the effect of an electrical stress on lubrication? Are they any synergistic interactions between mechanical and electrical stresses?
- ** Effect of the environment**: What is the effect of the environment (temperature, atmosphere) on the lubrication efficiency? To assess this topic, different tribometers (at room atmosphere, under controlled atmosphere and/or under-vacuum) will be used.

The PhD student will participate to the development of the experimental methodology, propose dedicated campaigns of experiments, prepare the samples, run the experiments, process the data and interpret the results in terms of physical-chemistry explanations.

The PhD student will have to collaborate with project partners, since similar experiments at lower scale will be performed at SIMaP lab (Grenoble, France).

Informations ________________________

Laboratory**:Laboratoire de Tribologie et Dynamique des Systèmes (LTDS - UMR 5513)**

Type of working contract**:Fixed term contract**

Working contract duration**:3 years**

Job starting date**:1**st** January 2025**

Job status**:PhD student**

Gross annual salary**:40 000€/year**

Required diploma**:Master research (M2)**

Required research experience**:Master degree internship**

Place of work: LTDS lab, **Ecully (FRANCE)**

**Laboratory presentation**: