1H NMR study of hydrogen self-diffusion in ternary Ti-V-Cr alloys

Here we report on the results of proton NMR study of hydrogen self-diffusion in hydrides of Ti-V-Cr alloys of different composition, pure and with 4 wt.% of Zr7Ni10 additives, namely, TiV0.8Cr1.2H5.29, Ti0.5V1.9Cr0.6H5.03 and Ti0.33V1.27Cr1.4H1.13. The measurements have been made using the static field gradient nuclear magnetic resonance technique. The hydrogen self-diffusion coefficient at room temperature lies within the range of 1.4-3.7 × 10−11 m2/s. The activation energy Ea strongly depends on the both composition and structure type of the hydride. The samples with bcc structure (and with the lowest hydrogen concentration) exhibit the highest Ea value of 0.2 eV. For the samples with fcc structure the Ea value is lower and decreases with increasing the vanadium fraction. The influence of Zr7Ni10 additives on the measured parameters is also discussed.