Electrochemical and metallurgical characterization of ZrCr1-xNiMox AB2 metal hydride alloys
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 s...
| Autores: | , , , , |
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| Tipo de documento: | artigo |
| Estado: | Versão publicada |
| Data de publicação: | 2015 |
| País: | Argentina |
| Recursos: | Consejo Nacional de Investigaciones Científicas y Técnicas |
| Repositório: | CONICET Digital (CONICET) |
| Idioma: | inglês |
| OAI Identifier: | oai:ri.conicet.gov.ar:11336/50156 |
| Acesso em linha: | http://hdl.handle.net/11336/50156 |
| Access Level: | Acceso aberto |
| Palavra-chave: | Hydrogen Laves Phase Metal Hydrides Molybdenum https://purl.org/becyt/ford/1.4 https://purl.org/becyt/ford/1 |
| Resumo: | 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. |
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