Sputtering of carbon–tungsten mixed materials by low energy deuterium

In the divertor of next step fusion experimental devices such as ITER, simultaneous presence of carbon and tungsten material will lead to their mixing during the redeposition process. In the present paper, sputtering experiments on C–W mixed material by low energy hydrogen beam had been performed. The C–W mixed material was simulated by the deposits during the D2 arc discharge between carbon and tungsten electrode. Five types of C–W mixed materials having different W concentrations which ranged from 0 to 75 wt% were used as the specimens for the sputtering experiment. It was found that the sputtering yield strongly depends on the W concentration in the C–W mixed materials. From the results of electron probe micro-analysis, it was indicated that carbon material is preferentially sputtered by chemical sputtering. The formation of W–C bonding is considered to be the reason for the low sputtering yields of C–W mixed material layers.