Vacuum plasma etching of 1 wt% La2O3 dispersed tungsten

Vacuum plasma etching of 1 wt% La2O3 doped tungsten alloy surfaces were carried out to refine the surface morphology for enhancing its bonding characteristics with copper for fusion reactor components. Three different gas compositions containing argon with zero, 14.3 and 25 vol% hydrogen were used to carry out the plasma etching from 30 to 120 s on the given samples. Mitutoyo surface roughness (Ra) measurement, FORM TALYSURF and scanning electron microscopy (SEM) were employed to measure the changes in the surface roughness. Plasma etching with 14.3 vol% hydrogen mixture was found to be the best in micro-roughening the alloy surface. The maximum increase of 44% in Ra value was obtained with this gas mixture, when etched for 90 s.