Determination of activation energy of ion-implanted deuterium release from W-Y₂O₃

The retention and release of deuterium in W-2%Y₂O₃ composite materials and commercially pure tungsten after they have been implanted by deuterium plasma (flux ～3.71×10²¹ D/m²·s, energy ～25 eV, and fluence up to 1.3×10²⁶ D/m²) are studied. The results show that the total amount of deuterium released from W-2%Y₂O₃ is 5.23×10²⁰ D/m²(2.5 K/min), about 2.5 times higher than that from the pure tungsten. Thermal desorption spectra (TDS) at different heating rates (2.5 K/min-20 K/min) reveal that both W and W-2%Y₂O₃ have two main deuterium trapped sites. For the low temperature trap, the deuterium desorption activation energy is 0.85 eV (grain boundary) in W, while for high temperature trap, the desorption activation energy is 1.57 eV (vacancy) in W and 1.73 eV (vacancy) in W-2%Y₂O₃.