Development of tungsten diamond composites for nuclear fusion applications – Materials Strand Project

Supervisor/s: Aneeqa Khan, Ed Pickering, Paul Mummery (University of Manchester).

This project will focus on the development and analysis of tungsten diamond composites for fusion applications, building on existing work with UKAEA and INFLPR where single layers of tungsten have been deposited on Chemical Vapour Deposition (CVD) diamond for use as a high heat flux material in a fusion reactor.

CVD diamond has many relevant properties that are often best-in-class compared to all other materials: isotropic thermal conductivity five times higher than copper at room temperature and very low thermal expansion, which combine to give diamond unparalleled thermal shock resistance, a key property to mitigate the effect of a transient thermal load. In addition, it sublimates instead of melting, has low chemical reactivity with hydrogen in a gas environment, forms strong carbide chemical bonds with many metals, including tungsten, has high tensile strength, and good resistance to neutron radiation damage. However, the erosion performance of the diamond is not optimal.

In order to improve the erosion resistance, we successfully demonstrated that we are able to coat commercially available CVD diamond with a 1 ┬Ám thick tungsten layer via pulsed laser deposition (PLD). This is highly innovative with the aim to maintain the superior CVD diamond thermal properties, but with an improved erosion performance thanks to the coating.

Objective 

The goal is to build on existing work where tungsten has been deposited on CVD diamond. This will contribute to the development of a multi layered composite tungsten diamond material in order to:

  1. reduce chemical reactivity,
  2. increase the erosion resistance to physical sputtering,
  3. marginal improved ductility at elevated temperatures, and
  4. quasi-self-repairing, since the diamond erodes until a new tungsten layer if the surface film is lost.

If the films are thin enough (< 10 microns approximately), then the bulk properties of the composite should be similar to diamond.

This project will work on developing tungsten diamond composites and potentially a multi-layer composite and testing it under fusion relevant conditions. The project will involve the use of materials characterization and testing facilities. There is also scope for modelling the material as well.

The project will be based at Manchester but will involve travel to other facilities to carry out experiments.

This project is offered by University of Manchester. For further information please contact: Aneeqa Khan (Aneeqa.khan@manchester.ac.uk.)

This project may be compatible with part time study, please contact the project supervisors if you are interested in exploring this.