Modification of tungsten coated carbon by low energy and high flux deuterium irradiation

Plasma sprayed tungsten coated carbon fiber composites (VPS-W/CX-2002U) and powder metallurgy tungsten (PM-W) have been exposed to a high deuterium flux (≃1022 m−2 s−1) with low energy (100 eV) in a range from 708 to 843 K. Surface modification and deuterium retention after the exposure have been investigated to prove the suitability of such materials in fusion devices. Blisters are formed on the PM-W by deuterium irradiation with a fluence of 7.5×1025 m−2. The amount of blisters and their average size increase with an increase of a fluence to 3.00×1026 m−2. On the other hand, no modification is observed on VPS-W/CX-2002U. Desorption of VPS-W/CX-2002U irradiated by deuterium is different from that of PM-W. The peak temperature of D2 and HD release from PM-W is about 703 K. However, the desorption curve of VPS-W/CX-2002U gradually increases with increasing temperature up to 1273 K.