Mechanochemical model of boundary lubrication

Boundary lubrication is the most critical lubrication regime. Surface asperities are in direct contact with each other and there is a significant risk of wear and high friction.

Lubricant additives are there to form adsorbed or chemically reacted layers (tribofilms) that protect surfaces from wear. There is a mechanochemical interplay between the contact mechanics and the formation of the tribofilm. This interplay is still not fully understood and most investigations are fully experimental.

There is a trial and error process to understand how lubricant additives react with the surface and the lubricant base fluid.

When two rough surfaces are in sliding contact, a stochastic variation of flash temperature, contact pressure, and surface stress arises. Temperature and stress activates the additives.

In the proposed research project, we want to develop a model that combines contact mechanics with chemical and physical modelling of the additives’ interaction with the surfaces and the base fluid.

The model will be in three scales, macro, micro, and atomic scales.Such model will help us to understand how the properties of the additive molecule interacts with the surface topographies. We will also be able to understand how to optimise the surface topography for completely new types of additives.

This will be a unique model and the success is based on the research team’s exceptional knowledge and experience in both contact mechanics and tribo-chemistry.