HYDROGEN ABSORPTION PROPERTIES OF PSEUDO-BINARY ALLOYS TI0.8ZR0.2MN1.5M0.5

Hydrogen absorption properties of Ti0.8Zr0.2Mn1.5M0.5 alloys have been investigated. The M represent the elements Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Al or Nb. All these alloys belong to Laves phase C14 (MgZn2) type structure and the lattice constants were measured. In order to aborb hydrogen it is necessary for the lattice constants a to be larger than 4.88 x 10(-10) m and c larger than 7.99 x 10(-10) m. V, Cr, Fe and Cu were appropriate elements to substitute for M. Especially, Ti0.8Zr0.2Mn1.5Cr0.5 alloy was an excellent candidate for hydrogen storage and purification. It exhibited perfect properties, i.e., a large capacity (H/M = 1.1), rapid hydrogen absorption, wide plateau [DELTA(H/W) = 0.95] and flat dissociation pressure of its hydride. With Al and Nb as the M the resultant alloys could also absorb a great quantity of hydrogen. But it was difficult to release the hydrogen and the plateau was destroyed. Ti0.8Zr0.2Mn1.5Ti0.5 Was not a single intermetallic compound though it absorbed hydrogen. With Mn, Co and Ni as M, the alloys did not absorb hydrogen.Chemistry, PhysicalSCI(E)