Hydrogen storage in Ti-based metal hydrides investigated by elastic recoil detection analysis (ERDA)

Highlights: • The elastic recoil detection analysis shows 41 at.% of H absorbed in CP-Ti. • The amount of hydrogen absorbed by Ti-6Al-4V alloy was 31 at.%. • Pd layer improved the hydrogen absorption capacity of Ti-6Al-4V alloy to 36 at.%. • The H depth profile shows the highest diffusion depth in CP-Ti. -- Abstract: Hydrogen storage capacity of CP-Ti, Ti-6Al-4V alloy, and Ti-6Al-4V alloy coated with a thin Pd layer was investigated. All samples were hydrogenated at 550 °C for 3 h in 15% hydrogen and 85% argon gas mixture. The hydrogen content and its depth profile were investigated using elastic recoil detection analysis (ERDA) while the X-ray diffraction was used for phase analysis. The highest average content of hydrogen of (41 ± 60) at.% was absorbed in CP-Ti while (31 ± 4) at.% H was determined in Ti-6Al-4V alloy. The presence of a thin Pd catalytic layer improved the hydrogen absorption of alloy to (36 ± 3) at.% H. With the beam energy of 3 MeV, H was profiled up to (4520 ± 410) × 10¹⁵ atoms/cm², (3250 ± 300) × 10¹⁵ atoms/cm² and (3950 ± 360) × 10¹⁵ atoms/cm² in CP-Ti, Ti-6Al-4V alloy and in the coated system respectively. The TiH₂ hydrides were found in all three systems in addition to Pd₃Ti phase in the Pd/Ti-6Al-4V coated system.