Skip to main navigationSkip to main content
The University of Southampton
Engineering

Research project: Nanoadditives for lubrication of hydrogen technology

Currently Active: 
Yes

The use of tungsten disulphide (WS2) nanoparticles in hydrogen applications may help reduce the effects of hydrogen permeation into steel.

Project Overview

When nascent metal surfaces generated in the wear processes are exposed to hydrogen environments they catalyse the decomposition of hydrogen gas molecules into atoms. In this form, hydrogen can permeate the metal surface and negatively influence its properties. Metal embrittlement has been identified as a major consequence of the hydrogen uptake and it represents an extra challenge for tribological parts which are normally subjected to high stresses.
Previous studies show that the amount of hydrogen that diffuses into the material is directly related to the reduction in service life.

Published research has shown that lubricants (both, oils and greases) can reduce metal permeation and uptake of hydrogen thus protecting the tribological parts. Lubricants can be designed to prevent the permeation of hydrogen and extend the service life of materials.

Recently, a particular interest has been directed to nanoadditives which can act as a barrier to hydrogen and prevent both, the formation of hydrogen atoms and their permeation into the substrate. These can be achieved because:

  • the nanosize of the additive particles can fill out the contact asperities and reduce the area of the nascent metal surface exposed to hydrogen
  • nanoadditives can form a protecting tribofilm on the contact surfaces

Amongst lubricant nanoadditives, WS2 nanoparticles have numerous advantageous properties but the most important one relevant to this application is their recently discovered ability to react with the steel substrate in high-pressure, high-temperature contacts and form a thick chemical tribofilm composed of iron and tungsten sulphides and oxides with a hardness superior to the conventional additives i.e. ZDDPs and OFMs (Fig. 1 and 2).

Alicona image of the tribofilm generated by WS2 nanoparticles
Fig 1

This project employs Thermal Desorption Spectroscopy, to investigate the action of WS2 NPs to reduce hydrogen uptake in rolling contact fatigue experiments. The effectiveness of WS2 tribofilms is compared against those generated by conventional antiwear, extreme pressure and friction modifier additives.

Recent experimental results have shown that WS2 nanoadditives have the potential to create a barrier against the permeation of hydrogen into steel. Their excellent tribological properties, combined with the ability to prevent hydrogen permeation can be the thought-after solution to the efficient and safe use of hydrogen in fuel cells and thus lead to a smooth transition towards the use of hydrogen as the main energy fuel of the future.

Auger elemental mapping of the WS2 tribofilm generated on the wear track after a 10 h test
Fig 2

This project employs Thermal Desorption Spectroscopy, to investigate the action of WS2 NPs to reduce hydrogen uptake in rolling contact fatigue experiments. The effectiveness of WS2 tribofilms is compared against those generated by conventional antiwear, extreme pressure and friction modifier additives.

Recent experimental results have shown that WS2 nanoadditives have the potential to create a barrier against the permeation of hydrogen into steel. Their excellent tribological properties, combined with the ability to prevent hydrogen permeation can be the thought-after solution to the efficient and safe use of hydrogen in fuel cells and thus lead to a smooth transition towards the use of hydrogen as the main energy fuel of the future.

Associated research themes

Materials and surface engineering

Related research groups

national Centre for Advanced Tribology at Southampton (nCATS)

Publications

Articles

Staff

Share this research project Share this on Facebook Share this on Google+ Share this on Twitter Share this on Weibo

We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we will assume that you are happy to receive cookies on the University of Southampton website.

×