Electrochemical and metallurgical characterization of ZrCr1-xNiMox AB2 metal hydride alloys

Authors
Erika, Teliz; Faccio Sgiorovello, Ricardo Juan; Ruiz, Fabricio Carlos; Fernando, Zinola; Verónica, Díaz
Publication Year
2015
Language
English
Format
article
Status
Published version
Description
The effects of partial replacement of chromium by molybdenum was studied on the structure and electrochemical kinetic properties of ZrCr1-xNiMox(x = 0.0, 0.3 and 0.6) metal hydride alloys. The arc-melting prepared alloys were metallurgically characterized by X-ray diffraction and energy dispersive spectroscopy microanalysis, which showed AB2 (with hexagonal C14 structure) and ZrxNiy (Zr7Ni10, Zr9Ni11) phases. After a partial substitution of chromium by molybdenum, secondary phases monotonically increase with the C14 unit cell volume indicating that most of molybdenum atoms locate in the B-site. The alloys were electrochemically characterized using charge/discharge cycling, electrochemical impedance spectroscopy and rate capability experiments that allowed the determination of hydriding reaction kinetic parameters. The presence of molybdenum produces a positive effect for hydrogen diffusion in the alloy lattice, and ZrCr0.7NiMo0.3 alloy depicts the better kinetics associated with a fast activation, lower charge transfer resistance and the best high rate discharge behavior. This fact would be related to a lower diffusion time constant and a bigger value of the product between exchange density current and surface active area. There is a trade-off in the amounts of secondary phase and Laves phases in order to improve the kinetic performance.
Fil: Erika, Teliz. Universidad de la República; Uruguay
Fil: Faccio Sgiorovello, Ricardo Juan. Universidad de la República; Uruguay
Fil: Ruiz, Fabricio Carlos. Comisión Nacional de Energía Atómica. Centro Atómico Bariloche; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina
Fil: Fernando, Zinola. Universidad de la República; Uruguay
Fil: Verónica, Díaz. Universidad de la República; Uruguay
Subject
HYDROGEN
LAVES PHASE
METAL HYDRIDES
MOLYBDENUM
Otras Ciencias Químicas
Ciencias Químicas
CIENCIAS NATURALES Y EXACTAS
Access level
Restricted access
License
https://creativecommons.org/licenses/by-nc-nd/2.5/ar/
Repository
CONICET Digital (CONICET)
Institution
Consejo Nacional de Investigaciones Científicas y Técnicas
OAI Identifier
oai:ri.conicet.gov.ar:11336/50156