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Effects of substituting Ni with Al on the microstructure and electrochemical performances of the as-cast and quenched La–Mg–Ni-based (PuNi3-type) hydrogen storage alloys
- Source :
-
Materials Chemistry & Physics . Sep2007, Vol. 105 Issue 1, p86-91. 6p. - Publication Year :
- 2007
-
Abstract
- Abstract: In order to improve the cycle stability of La–Mg–Ni system (PuNi3-type) hydrogen storage alloy, Ni in the alloy was partially substituted by Al, and La0.7Mg0.3Ni2.55−x Co0.45Al x (x =0, 0.1, 0.2, 0.3, 0.4) hydrogen storage alloys were prepared by casting and rapid quenching. The effects of substituting Ni with Al on the microstructures and electrochemical performances of the as-cast and quenched alloys were investigated in detail. The results obtained by XRD show that the as-cast and quenched alloys have a multiphase structure, including the (La, Mg)Ni3, the LaNi5 and the LaNi2 phases. The substitution of Al for Ni increases the amount of the LaNi2 phase in the as-cast alloys, but it has an inappreciable influence on the abundance of the LaNi2 phase in the as-quenched alloy. The results obtained by SEM and TEM indicate that the substitution of Al for Ni leads to the grains of the as-quenched alloys coarsen and restrain an amorphous phase formed in the as-quenched alloys. The results of the electrochemical measurement indicate that the capacities of the as-cast and quenched alloys monotonously decrease and their cycle stabilities significantly increase with the increase of Al content. When the amount of substitution Al for Ni increased from 0 to 0.4, the cycle life of the as-cast alloys increased from 72 to 132 cycles, and that of the as-quenched (20ms−1) alloys from 86 to 134 cycles. [Copyright &y& Elsevier]
- Subjects :
- *METALLIC composites
*ALLOYS
*INORGANIC chemistry
*NATURAL resources
Subjects
Details
- Language :
- English
- ISSN :
- 02540584
- Volume :
- 105
- Issue :
- 1
- Database :
- Academic Search Index
- Journal :
- Materials Chemistry & Physics
- Publication Type :
- Academic Journal
- Accession number :
- 26147903
- Full Text :
- https://doi.org/10.1016/j.matchemphys.2007.04.033