Abstract
Modern nickel/metal hydride batteries and cryogenic refrigerators based on hydrogen absorption rely heavily on the rare-earth intermetallic compound LaNi5. Proper stoichiometry is crucial to obtain optimum performance in this compound. Oxygen segregation during solidification of these materials can lead to depletion of lanthanum through the formation La2O3. This, in turn, can greatly reduce the phase purity of these materials, thus limiting their performance in many applications. A series of LaNi5 alloys were produced by nonconsumable arc melting with various oxygen contents. These alloys were investigated principally by Auger spectroscopy. Correlations were made between the solidification microstructure and the oxygen content at a known solidification rate. Hydrogen storage capacities were also measured to evaluate the absorption properties of the solidification-derived microstructure. Increasing oxygen content was found to reduce the hydrogen absorption capacity of these materials.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
T. Sakai et al., “Rechargeable Hydrogen Batteries using Rare-Earth-Based Hydrogen Storage Alloys,” J. Alloys and Compounds, 180 (1992), pp. 37–54.
K.A. Gschneidner, Jr., “Metals, Alloys and Compounds—High Purities Do Make a Difference,” J. Alloys and Compounds, 193 (1993), pp. 1–6.
A.V. Klimymenko et al., “Structure of LaNi2.286 and the La-Ni System from LaNi1.75 to LaNi2.50,” J. Alloys and Compounds, 144 (1988), pp. 133–141.
Y.Y. Pan and P. Nash, “Lanthanum-Nickel Phase Diagram,” Phase Diagrams of Binary Nickel Alloys, ed. P. Nash (Metals Park, OH: ASM, 1991).
R. Mishima, “Rapidly Solidified Hydrogen Storage Alloy by Melt Spinning Method and Its Characteristics as a Metal Hydride Electrode,” Rare Earths, Materials for the 21st Century, ed. G. Adachi, (Kyoto Japan, Proceedings of the Rare Earth Conf., June 1–5, 1992), pp. 178–179.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Ellis, T.W., Jones, L.L. & Bloomer, T.E. Effects of oxygen on the solidification microstructure of LaNi5 . JOM 47, 47–49 (1995). https://doi.org/10.1007/BF03221408
Issue Date:
DOI: https://doi.org/10.1007/BF03221408