Hydrogen Diffusion Behavior in Titanium-Chromium Hydrides with Laves Structures

摘要

Extensive NMR measurements of the proton relaxation times have been performed on low (i.e., alpha -phase) and intermediate (i.e., alpha -phase) hydrogen concentrations in TiCr sub 2 H/sub x/ with both the hexagonal C14 and cubic C15 Laves structures. The relaxation times indicate rapid diffusion rates above 200 K for all the TiCr sub 2 H/sub x/ phases; however, large differences in the diffusion activation energies are observed. This behavior is associated with the hydrogen interstitial site occupancies and diffusion pathways becoming restricted in the C14 structure.