钨涂层面对等离子体材料出气性能的研究

Gas desorption behavior of plasma facing material for tungsten coating

钨由于高熔点、低溅射率等优点而被广泛的认为是最有希望的核聚变装置面对等离子体材料。然而考虑到等离子体约束和边界气体再循环,钨涂层面对等离子体材料在真空中的出气性能的研究是十分重要的。研究结果显示钨涂层主要出气种类为H2,H2O,O2,CO/N2和CO2。在300℃、经过4小时的烘烤,涂层出气率有明显的降低,特别是H2O和CO/N2;继续烘烤对涂层出气率改善效果不显著,因此真空等离子体喷涂钨涂层在用作面对等离子体材料时,仍需要烘烤、放电清洗等壁处理手段。

Due to its high melting point and low sputtering rate, the tungsten is considered as a highly promising candidate of plasma facing material （PFM） in nuclear fusion systems. However, in view of plasma confinement and its boundary gas recycling, the investigation on the gas desorption behavior of plasma facing material for tungsten coating is very important. The results indicated that the desorbed gases from tungsten coating are mainly the H2, H2O,O2, CO and CO2. The rate of gas desorption from W coating decreases obviously after baking at 300℃ for 4hr, especially that of H2O and CO/N2. But lengthening the baking time further has no obvious effect on improving the rate of gas desorption. A conclusion is therefore drawn that the discharge clearing is still necessary in addition to baking for wall clearing if tungsten is used as PFM for VPSW coating in nucleer fusion systems.