Study on compatibility of liquid Sn and tungsten mesh under high temperature and plasma environment

Abstract:

In this paper, the wettability and corrosion behavior of liquid tin (Sn) on tungsten-based capillary porous meshes structure (CPS) under static high temperature and high density hydrogen plasma were investigated by vacuum tube furnace and Sichuan University plasma-material surface interaction platform (SCU-PSI). The experimental results show that the threshold temperature of liquid Sn wetted tungsten mesh (four layers 150 mesh) is 950 ℃ under static high temperature environment, and the wetting effect becomes better with the increase of experimental temperature. When the experimental temperature reached 1050 ℃, a large number of stannic oxide rod-like structures were observed on the surface of the tungsten screen. This rod-like structure may be due to the presence of a small amount of oxygen in the tubular furnace. Sn reacts with oxygen at high temperature to form SnO2 nanocrystals. When the liquid Sn-CPS structure was irradiated again by hydrogen plasma with an ion flux of 7.71×1022 m-2*s-1 and a heat load of 54.55 kW*m-2, a large area of fracture occurred in the tungsten sieve and a filamentous structure was formed. However, no similar damage occurred on the surface of the tungsten sieve without liquid Sn wetting. It is suggested that under the high density hydrogen plasma irradiation, the synergistic action of hydrogen plasma and SnO2 may aggravate the damage of tungsten screen, resulting in tungsten wire hardening and fracture. The experimental results provide a theoretical basis for the future application of liquid Sn-CPS in fusion devices.