Behavior of tungsten with exposure to deuterium plasmas

Four kinds of tungsten (W) materials, i.e. (1) foil of 50 μm thick (f-W), (2) polycrystalline (Pc-W) with grain size of ∼3 μm, (3) recrystallized (Re-W) with grain size of ∼50 μm and (4) vacuum plasma spraying (VPS-W) coatings, were irradiated employing linear plasma generators, with fluxes ⩾1 × 1022 D/m2/s and energies ⩽100 eV/D. Scanning electron microscopy (SEM) was used to observe blister formation at the surfaces. The SEM surface morphology and cross section observation indicates that blister formation is related to the microstructure and surface state of different material grades. Results of trapping and deuterium retention measured by thermal desorption spectroscopy (TDS) and nuclear reaction analysis (NRA) show also a close correlation between the retention and the microstructure and surface state.