Incorporation of Hydrogen in Carbon-Tungsten Co-Deposition Layers Formed by Hydrogen Plasma Sputtering

Carbon based material and tungsten are used in ITER as plasma facing materials in the divertor region. Presumably, carbon-tungsten mixed materials will be formed on the surface of the inner components of the vacuum vessel. Therefore, it is necessary to understand incorporation phenomena of hydrogen into carbon-tungsten mixed materials. In this study, carbon-tungsten co-deposition layers were formed by sputtering method using hydrogen RF plasma. Hydrogen incorporation was investigated as a function of atomic ratio of carbon and tungsten contained in the layer. The obtained hydrogen retention was in the range between 0.16 and 0.83 as H/(C+W). The carbon ratio dependence on hydrogen incorporation was not observed. It was found that the release behavior of the incorporated hydrogen changes depending on the atomic ratio of C and W in the layer.