Behavior of B4C coating on tungsten under exposition on T-10 tokamak plasma

It was shown (Buzhinsky, 2003) that in situ renewable coating of boron carbide can protect the tiles of the divertors of thermonuclear facilities from destruction and also to prevent accumulation of remarkable amounts of tritium in the plasma facing materials. In the paper presented a plasma method for deposition of boron carbide coating with a high adhesion to tungsten was developed. In the laboratory installation boron carbide coating on tungsten was subjected to cycling irradiation by the deuterium ion flux with power density up to 5.0 MW/m² in the temperature range up to 1500 K. The results of the tests showed that the composition, integrity and adhesion of the coating were not violated in the laboratory tests. In the T-10 tokamak the behavior of the coating was investigated in the temperature range up to 3600 K when irradiated with plasma power in the range of 20–100 MW/m² during plasma disruption. Being irradiated in T-10 tokamak, the coating retained its continuity, adhesion and protected tungsten from the effect of the even at temperatures of 2500–3600 K, when the coating melted under irradiation and its composition changed to B:C ≈ 1:1. (paper)