Hydrogen absorption in vanadium- and niobium-based topologically close-packed structures

Hydrogen absorption properties of Franck-Kasper phases formed in V-Ni and N b-Ni systems have been investigated systematically. The Al5 V-Ni phase abso rbs up to 0.85 H/M under a pressure of 84 bar, the sigma V-Ni phase absorbs 0.46 H/M under 75 bar and mu Nb-Ni absorbs 0.10 H/M under 50 bar. The pres sure-composition curves were measured for those alloys at 25 degreesC. Subs titution of V by Nb and Ti in sigma V-Ni phase does not lead to significant changes in hydrogenation properties of this phase. (C) 2001 Elsevier Scien ce B.V. All rights reserved.