The Structures and Hydrogen Absorption-Desorption Properties of V40-Fe8-Ti-Cr(Ti/Cr=0.95~1.20) Alloys

Abstract:

The structures and hydrogen absorption-desorption properties of V40-Fe8-Ti-Cr(Ti/Cr=0.95~1.20) alloys were investigated. All the studied alloys are single-phase with bcc structure. With the decrease of Ti/Cr ratio, the lattice parameters decrease, plateau pressures increase, and hydrogen absorption capacities increase first, then decrease. The V40Ti26Cr26Fe8 alloy with a Ti/Cr ratio of 1.00 has the maximum hydrogen desorption capacity of 2.4% mass fraction with a plateau pressure of 0.24 MPa at 298 K. ΔH and ΔS of the V40Ti26Cr26Fe8 alloy are –39.6 kJ·mol-1H and –140.3 J·mol-1·K-1, respectively, and its plateau pressure at 423 K is calculated to be 27.5 MPa