Effect of particle size and microstructure on the hydrogen storage property in a V-Ti-Cr solid solution system

Nano-particles of V-Ti and V-Ti-Cr alloys with a BCC (Body Centered Cubic) structure were prepared via the EEW (electric explosion of wire) method. However, due to the formation of chromium oxide (CrO _0.87) and/or vanadium oxide (V ₁₆O ₃) during the explosion, the exploded particles were deficient in Cr and V content, contrary to the anticipated composition, and micro-particles also formed in addition to the nano-particles. The hydrogen storage capacity of the exploded particles decreased compared to that of mechanically crushed particles from ingots, because the number of interstitial sites for hydrogen in the lattice was reduced due to the increased surface area and also because the BCC phase decreased as a result of the formation of oxide phases. As the lattice parameters of the alloys became small, the plateau pressure in the P-C isotherm increased because it was more difficult for hydrogen to diffuse through the lattice. It was also found that the strain induced by adding other elements in the V lattice reduced the hysteresis in the P-C isotherm.