Lithium (Li) coatings on plasma facing components (PFCs) have been proposed as potential solutions to first wall and divertor challenges in tokamak fusion reactors. We report on the thermal behavior of ultrathin pure Li films deposited on polycrystalline substrates of molybdenum (Mo) and a molybdenum alloy (titanium zirconium molybdenum, TZM). These Li films were studied under controlled ultrahigh vacuum (UHV) conditions and thermal stabilities were primarily compared via temperature programmed desorption (TPD) measurements. In addition, on TZM, which is of particular interest, we obtained additional spectroscopic data using Auger electron spectroscopy (AES) and low energy ion scattering (LEIS) to further characterize the film structure and composition. The monolayer of Li in these films in contact with the substrate is bound much stronger than in bulk Li films, and thermally desorbs at much higher temperatures. Interfacial Li on Mo(poly) has a higher thermal stability than that on TZM(poly), where the limiting values for the desorption activation energies, E_d, are 3.56 and 2.84 eV, respectively, in the low coverage, high temperature desorption tail. LEIS indicates some clustering or interdiffusion of the Li films on the TZM substrate at 500 K. No appreciable irreversible absorption of Li occurs on Mo or TZM under the conditions of these experiments.

已提出在面向等离子体的组件（PFC）上使用锂（Li）涂层作为托卡马克聚变反应堆中第一道壁和分流器难题的潜在解决方案。我们报告了沉积在钼（Mo）和钼合金（钛锆钼，TZM）的多晶衬底上的超薄纯Li膜的热行为。在可控的超高真空（UHV）条件下研究了这些Li膜，并主要通过程序升温脱附（TPD）测量对热稳定性进行了比较。此外，在特别感兴趣的TZM上，我们使用俄歇电子能谱（AES）和低能离子散射（LEIS）获得了更多的光谱数据，以进一步表征薄膜的结构和组成。与主体的Li膜相比，这些膜中与基材接触的Li单层的结合力要强得多，并且在更高的温度下会发生热脱附。Mo（poly）上的界面Li具有比TZM（poly）更高的热稳定性，其中解吸活化能E的极限值在低覆盖率，高温解吸尾部中，_d分别为3.56和2.84 eV。LEIS表明在500 K时TZM衬底上的Li膜有一些聚集或相互扩散。在这些实验条件下，Mo或TZM上没有发生不可逆的Li吸收。