Kinetics of hydride formation in massive LaAl0.25Ni4.75 samples

Z. Haberman, J. Bloch, M. H. Mintz, I. Jacob

Research output: Contribution to journalArticlepeer-review

11 Scopus citations


Hydrogen pressures, ranging from 80 to 1 atm, were utilized to study the hydriding kinetics of small, well-shaped LaAl0.25Ni4.75 samples at temperatures between 246 K and 281 K. The hydrogen absorption was monitored as a function of time at constant temperature and approximately constant pressure. Either a shrinking core (sc) or a low-dimensional nucleation and growth (ng) models fit the experimental data. In one case an interesting feature of thin cracked layer, consisting of bent flakes was revealed in a SEM micrograph of a partly hydrogenated sample. This observation is examined in view of the above models. The pressure dependence of the rate constants indicates an interface-controlled phase transition as the hydride formation rate-determining step. The activation energy for the hydriding process is estimated from Arrhenius plots of the reaction rates to be 0.25 eV/H atom. The results are compared with kinetic data of hydride formation in massive LaNi5 and powdered LaAl0.25Ni4.75 samples.

Original languageEnglish
Pages (from-to)556-559
Number of pages4
JournalJournal of Alloys and Compounds
StatePublished - 20 May 1997


  • Hydride formation
  • Kinetics
  • LaAlNi

ASJC Scopus subject areas

  • Mechanics of Materials
  • Mechanical Engineering
  • Metals and Alloys
  • Materials Chemistry


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