ABSTRACT
A Ti-Ni binary phase system contains three intermetallic stable phases—Ti2Ni, TiNi, and TiNi3—and several metastable intermetallic phases. The Ti-Ni system belongs to a typical Brewer hypo-hyper-d-electronic combination of transient metals. Hydrogen storage properties of Ti-Ni materials have been investigated by many researchers. Ti2Ni alloy is a promising anode material for nickel/metal-hydride batteries and a material for gaseous hydrogen storage due to its relatively high hydriding-dehydriding kinetics, ability to remain stable in an electrolyte and reasonable specific capacity. TiNi alloy material is characterized by low specific weight, high hydrogen capacity per unit weight, and good oxidation resistance, which is desirable in hydrogen storage materials. Discharge capacity of TiNi alloy is influenced by the maximum discharge capacity of the alloy and the discharge kinetics which is determined by the electrochemical polarization and concentration polarization. Electrochemical properties of mechanically alloyed Ti-Ni alloys can be improved by chemical modification.
