Corrosion studies of LiH thin films

• Published in: Journal of nuclear materials Vol. 484; pp. 228 - 235
• Main Authors: Tonks, J.P., King, M.O., Galloway, E.C., Watts, J.F.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.02.2017; Elsevier BV
• Subjects: Auger spectroscopy; Corrosion; Corrosion products; Decomposition; Electron spectroscopy; Evaporation; High vacuum; Photoelectron spectroscopy; Reaction mechanisms; Spectroscopy; Studies; Temperature; Thin films; Vacuum; X ray photoelectron spectroscopy
• ISSN: 0022-3115; 1873-4820
• DOI: 10.1016/j.jnucmat.2016.12.008

Thin films of LiH and its corrosion products were studied using temperature programmed decomposition (TPD), x-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES). Thin films were grown on Ni(100) in an ultra high vacuum system using an electron beam evaporator. Characteristic Li KLL AES peaks were identified for Li, LiH, Li2O and LiOH which facilitated identification of thin film composition. XPS of the O 1s region revealed three distinct chemical shifts which were attributed to Li2O, LiOH and chemisorbed H2O. We show that exposing LiH to very low H2O partial pressures results in formation of LiOH/Li2O domains on LiH. We also show that these XPS peaks can be linked to reaction mechanisms in the TPD profiles. TPD traces have been explicitly modelled to determine the activation energies of the reactions and compare favourably with previous measurements on bulk LiH samples. •Thin films of high purity LiH, LiOH and Li2O have been produced.•O1s XPS shows separate peaks for LiOH and Li2O.•LiH exposed to low H2O doses shows the presence of both LiOH and Li2O.•With higher doses, chemisorbed H2O is observed.•Decomposition kinetics of thin films are similar to previous bulk studies.