The erosion and retention properties of α-WC films by low-energy deuterium ion irradiation

Abstract

Since WC can be easily formed on tungsten (W) surface through the interaction between the plasma and W surface in the C-containing impurity atmosphere in tokamaks, the investigation on erosion and deuterium (D) retention behaviors of WC is mandator for stable plasma operation. In this work, α-WC films were successfully prepared by combining reactive magnetron sputtering and thermal annealing, then irradiated by D ions. The WC shows W sputtering yield smaller than pure W, and it is almost independent with temperature. Thus, the erosion of WC could be mainly described by physical sputtering. The crystalline of WC has been improved after irradiation, and the surface shows a dominant metallic W phase due to preferential sputtering of C. D concentration in WC is 5 times higher than that in W through elastic recoil detection analysis, mainly because the Frenkel defect pairs induced by D irradiation and interstitial sites can trap D in large quantities, and their D profiles are similar. But different from W in double desorption peaks, D2 desorption on WC is a single peak whose temperature is close to the low temperature peak of W. This work provides a further understanding in erosion and deuterium retention behaviors of WC.