Basic study on lithium coating and plasma-surface processes

1. 锂包覆技术的建立研究了蒸发法制备锂包覆。实验发现，在400℃左右的烘箱温度可以很容易地控制蒸发速度，为了抑制加热烘箱中的杂质，采用射频感应加热，有效地加热锂本身，而不加热其他材料。锂与各种气体的化学反应研究了锂膜与O_2、H_2、CH_4、CO等不同气体的化学反应性。发现锂与氧气的反应性很强，当氧气进入容器时，被涂覆的锂膜被完全氧化。CO和CH_4也与锂发生反应，但反应仅限于锂膜表面的几层。氢不与锂膜反应。锂膜与氢等离子体的相互作用研究了锂膜与氢直流发光等离子体的相互作用。锂膜吸收大量的氢。3 .氢的吸收几乎与包覆的锂相当，这意味着一个锂原子与一个氢原子发生反应，氢渗透到锂膜的大部分，而不考虑氢离子进入锂膜的离子注入范围（小于几百纳米）。JIPPT-IIU聚变实验装置的锂涂层。锂涂层成功应用于国家聚变科学研究所jippt - iu聚变实验装置。jippt - iu容器壁上蒸发了0.5g锂，涂层面积约为Im^2。结果表明，在托卡马克放电初期，氢的再循环减少，氧和碳的杂质减少。

1. Establishment of Lithium Coating TechniqueLithium coating with evaporation method is investigated. It was found that the evaporation speed can be easily controlled by the oven temperature around 400 C.To suppress impurity from heated oven, RF inductive heating is used, which effectively heat the lithium itself without heating other materials.2. Chemical reaction of lithium with various gasesChemical reactivity of lithium film with various gases such as O_2, H_2, CH_4 or CO was investigated. It is found that the lithium is highly reactive with the oxygen gas, and the coated lithium film is completely oxidized when the oxygen gas is fed into the vessel. CO and CH_4 are also reactive with lithium, but reaction is limited up to a few monolayrs of lithium film surface. Hydrogen does not react with lithium film.3. Interaction of lithium film with hydrogen plasmaInteraction of lithium film with hydrogen DC glow plasma is investigated. Lithium film absorbs large amount of hydrogen. Hydrogen absorption is almost comparable to the coated lithium, which implies that the one lithium atom reacts with one hydrogen atom, and that the hydrogen penetrates into bulk of lithium film irrespective to the ion implantation range of hydrogen ion into the lithium film (less than a few hundred nano-meters).4. Lithium coating of JIPPT-IIU fusion experiment device.Lithium coating is successfully applied to the JIPPT-IIU fusion experiment device at National Institute for Fusion Science. Lithium (0.5g) is evaporated on the vessel wall of JIPPT-IIU,with coating area of about Im^2. It was found that the hydrogen recycling is reduced in the initial stage of tokamak discharge, and that the oxygen and carbon impurities is reduced.