INIFTA 05425
INSTITUTO DE INVESTIGACIONES FISICO-QUIMICAS TEORICAS Y APLICADAS
Unidad Ejecutora - UE
artículos
Título:
Study of the different ZrxNiy phases of Zr-based AB2 materials
Autor/es:
F. C. RUIZ; E. B. CASTRO; H. A. PERETTI; A. VISINTIN
Revista:
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
Editorial:
PERGAMON-ELSEVIER SCIENCE LTD
Referencias:
Año: 2009
ISSN:
0360-3199
Resumen:
Hydride-forming alloys are used as components of the negative electrode of nickel-metalhydride (NiMH) batteries. In previous works, the study of Zr-based AB2-type alloys indicatedthat the material without heat treatment (annealing) had better electrochemicalcharacteristics than the annealed one. The effect was attributed to the presence ofsecondary phases ZrxNiy formed during the solidification of the alloy button obtained byarc melting, and to the fact that these phases diminished their concentration or disappearedupon annealing. The main secondary phases formed by microsegregation areZr7Ni10, Zr9Ni11 and Zr8Ni21.In order to explain the effect of each one of these micro-segregations, alloys of the above mentioned composition were prepared by arc furnace and studied separately using powdermixtures of each ZrxNiy phase and annealed ZrCrNi alloy.The electrochemical impedance data analysis of each ZrxNiy alloy, using a model developedin our laboratory, allowed the identification of structural, physicochemical and kineticparameters which determine the performance of each material. Based on this analysis itmay be concluded that Zr8Ni21 alloy has the greatest hydrogen diffusion coefficient, beingthis parameter determinant of the charge/discharge performance of the alloy.
