Performance of a dual-process PVD/PS tungsten coating structure under deuterium ion irradiation

Abstract

A dual-process coating structure was developed on a graphite substrate to improve the performance of the coating structure under anticipated operating condition of fusion devices. A thin multilayer W/Mo coating (6 mu m) was deposited by physical vapor deposition (PVD) method with a variation of Mo interlayer thickness on plasma spray (PS) W coating (160 mu m) of a graphite substrate panel. The dual-process PVD/PS W coatings then were exposed to 3.08 x 10(24) D m(-2) of 100 eV D ions with a flux of 1.71 x 10(21) D m(-2) s(-1) in an electron cyclotron resonance (ECR) chamber. After irradiation, surface morphology and D depth profiles of the dual-process coating were analyzed and compared to those of the simple PS W coating. Both changes in surface morphology and D retention were strongly dependent on the microstructure of surface coating. Meanwhile, the existence of Mo interlayer seemed to have no significant effect on the retention of deuterium. (C) 2016 Elsevier B.V. All rights reserved