Reduction of Hydrogen Absorption of Vanadium Alloy Used for Fusion Blanket Material

For vanadium alloy, Ti-O coating was made by a reactive sputtering in order to reduce hydrogen absorption. After the annealing of vanadium alloy with Ti-O film in vacuum, the atomic composition and film thickness were examined by Auger electron spectroscopy. Both the atomic composition and film thickness remained the same after the annealing with a temperature lower than 773 K. The vanadium alloy with Ti-O film was exposed to hydrogen gas environment at 573 K, and then the hydrogen absorption rate was measured. In this measurement, the film thickness of the sample was changed. The hydrogen absorption rate decreased with increase of the film thickness when the thickness was less than approximately 0.5μm. In the case that the film thickness was 0.5μm, the absorption rate was approximately 50 times reduced, compared to the case without the coating.