Enhancing Tungsten’s Nitride Formation with Ion Implantation Technique

12/04/2024

Nuclear fusion offers a promising solution to address the growing global energy demand and supply security concerns. Efficient fusion reactor operation requires maintaining plasma purity, a task primarily performed by the divertor. Developing strategies to prolong its lifetime is critical for sustainable fusion energy. Nitrogen seeding experiments, initially aimed at mitigating divertor thermal loads, revealed the potential of tungsten nitrides (WNx) as plasma-facing materials. In this work, WNx were produced by implanting 2 x 10^18 and 2 x 10^17 N/cm^2 with energies of 150 keV and 30 keV, respectively at room temperature. The thickness and composition of the obtained “alloy” layer were determined by RBS. To study its behaviour under fusion conditions, 2 x 10^18 He/cm^2 and 2 x 10^18 D/cm^2 with energies of 20 keV and 10 keV were sequentially implanted, and the resultant samples were analysed by SEM and GIXRD. D retention in the obtained layer was measured by NRA with the D(3He,p)4He nuclear reaction. The sequential use of two nitrogen implantation energies proved effective in achieving a homogenous layer with significant thickness. It was identified the presence of β-W2N and h-W2N3 in the N-implanted W. Notably, the formation of the latter phase by ion implantation has not been previously reported in any study. The implanted layer exhibited 32% D retention after He and D implantation, significantly higher than the 4% measured for the W substrate. The performance of the obtained material as plasma facing material remains inconclusive, being necessary additional studies.

Authors in the community:

• 

  D

  Diogo Sampaio Pereira

  ist196115

Supervisors of this institution:

• 

  R

  Rodrigo Clemente Velez Mateus

  ist24807

• 

  N

  Norberto José Sobral Catarino

  ist25572

mechanical-engineering - Mechanical engineering

por - Portuguese

Instituto Superior Técnico