GD-OES study of the influence of second phase particles on the deuterium depth distribution in dispersion-strengthened tungsten

Dispersion-strengthened tungsten materials represent a new class of W-based materials to be investigated for use as plasma-facing component in nuclear fusion reactors. However, the retention and permeation characteristics of these materials under low energy deuterium (D) irradiation need to be elucidated before the efficacy of these materials can be judged. Due to possible deep penetration of D in W, depth profile techniques such as glow discharge optical emission spectroscopy (GD-OES) are needed to probe D concentrations many microns beneath the material surface. In this study, the D retention behavior of W materials containing 1–10 wt% TaC, TiC, or ZrC are investigated with GD-OES. After exposure to a 5 × 10¹⁸cm⁻² D ion fluence at 100 °C, D was observed beyond the D implantation depth the surface in many specimens, and the D depth profile was found to depend on the type and concentration of the added second phase. Combined with in-situ X-ray Photoelectron Spectroscopy (XPS) studies, the effects of impurity oxygen atoms on the D retention is considered, as an increasing oxygen content correlates with decreased D retention. The influence of grain size, second phase particles, and oxygen content on the retained D depth and concentration in these complex W-based materials is discussed.