Binary beryllium–tungsten mixed materials

Both Be and W are planned as wall materials for ITER. Although these materials will dominate the ITER first wall, and despite the fact that their interaction during operation will be dominated by surface processes, mostly bulk material data on the Be–W binary system are available. This article describes investigations of thin films of Be deposited on W, the inverse system (W films on Be), as well as experiments where W surfaces are exposed to a Be-seeded deuterium plasma. The formed alloy phases Be2W and Be12W are identified by X-ray photoelectron spectroscopy (XPS) and depth profile data both from sputter-XPS and MeV ion beam analysis are presented.