Self passivating W-based alloys as plasma-facing material

Self passivating tungsten-based alloys may provide a major safety advantage in comparison with pure tungsten (W) which is presently the main candidate material for the plasma-facing protection of future fusion power reactors. Films of binary and ternary tungsten alloys were synthesised by magnetron sputtering. The oxidation behaviour was measured with a thermobalance set-up under synthetic air at temperatures up to 1273 K. Binary alloys of W–Si showed good self-passivation properties by forming a SiO2 film at the surface. Using the ternary alloys W–Si–Cr, W–Si–Y, and W–Si–Zr the oxidation behaviour could be further improved.