Second phase and electrode characteristics of rare-earth-based AB5+x alloys
1995; Elsevier BV; Volume: 231; Issue: 1-2 Linguagem: Inglês
10.1016/0925-8388(95)01724-0
ISSN1873-4669
AutoresHong Cun-Mao, Yufen Zhang, Wang Jian,
Tópico(s)Electrostatics and Colloid Interactions
ResumoRare-earth-based alloys with overall composition AB5+x have been investigated, where A represents a lanthanum-rich mischmetal (Ml) and B contains the elements Ni, Co, Mn and Al. The results indicated that with x < 0.2 the alloys exhibited a single-phase AB5 compound having hP6(CaCu5) hexagonal structure and with x ⩾ 0.2 a second phase could be observed. The double-phase alloys showed more rapid absorption of hydrogen, a flatter P-C-T plateau and better electrode characteristics than does the single-phase AB5 alloy. So it was more suitable as negative-electrode materials in NiMH batteries. According to X-ray diffraction analyses, the main phases of the AB5+x alloys was formed by the AB5 compound and the second phase belongs to cubic structure with a reasonable composition of AlNi3, which had a strong catalytic ability for the reaction of hydrogen with AB5 alloys. Hence this led to an increase in the utilization ratio of hydrogen capacity.
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