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 carbontungsten 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.