Hydrogen permeation through disordered nanostructured tungsten films

摘要: Abstract We report results on long-term hydrogen outgassing and permeation studies of structurally highly disordered tungsten films, deposited 40 mm diameter permeable Eurofer substrates, using the Pulsed Laser Deposition technique. Hydrogen interaction with is becoming a relevant topic since was recognized as most promising candidate for first wall future fusion reactors. Prediction isotopes migration their abundance after plasma exposure uncertain due to great role played by structural disorder that formed W surface. Vacancy sites are theoretically predicted trap multiple H atoms exothermically, but density potential influence permeability has not been experimentally investigated yet. In our work, films having different thicknesses (1 10 μm) initially extremely low, gradually increasing over several-day campaign. The final values at 400 °C, lying between P = 1.46 × 10−15 mol H2/(m s Pa0.5) P = 4.8 × 10−15 mol H2/(m s Pa0.5), were substantially lower than those known well ordered films. Surprisingly, 10 μm thick film contained very high amount hydrogen, ∼0.1 H/W, which releasing during twenty-day