UTILITY TEST ON PROLONGING LIFE TIME OF HYDRIDE BATTERY WITH NANO-CRYSTALLIZED RARE-EARTH JYDROGEN ABSORBING ALLOYS

本研究的目的是获得非晶或纳米晶化的LaNi_5相，以延长现有镍氢电池的使用寿命。(1)发展由LaNi_5相嵌入非晶相组成的微观组织的合金：本研究通过熔融纺丝成功制备了大成分范围的La-Ni-B体系的非晶相。在（LaNi_5）_<0.8 ~ 0.7> (LaNi_<12>B_6)_<0.2 ~ 0.3>的组合物中，LaNi_5相的形成温度约为500‰。PCT测量结果表明，非晶态合金的氢吸收量很小，热处理后的结晶合金的氢吸收量增加，约为0.9mass%。(2)低B含量La-Ni-B合金的非晶态形成及其吸氢性能：LaNi_3B_<0.5>M_<0.5>(20at%La-10at%B)、LaNi_<3.25>B_<0.25>M_<0.5>(20at%La-5at%B)、LaNi_<4.85>B_<0.3>M_<0.5>(15at%La-4.5at%B)组成合金研究了低B含量La-Ni-B合金的非晶态形成。只有LaNi_3B_<0.5>M_<0.5>合金形成非晶相，该非晶相吸收了0.6质量%的氢。其余合金如LaNi_<3.25>B_<0.25>M_<0.5>均由近LaNi_5单相组成，吸收氢后变为非晶相。而LaN_<14.85>B_<0.3>M_<0.5>合金在2MPa氢压力下对所有附加元素的氢吸收率约为1质量%。经过30次氢化物-脱氢循环试验，这些结晶合金与LaNi_5合金相比几乎没有退化，特别是添加铁的合金具有防止合金粉化的作用。

The purpose of the present studies is to obtain amorphous or nano-crystallized LaNi_5 phases for prolonging the life time of presently used Ni-hydrides batteries.(1) Development alloys with microstructures consisted of LaNi_5 phases embedded in amorphous phases :The present study successfully prepares the amorphous phase in large compositional range of La-Ni-B systems by melt-spinning. The temperature that LaNi_5 phase is formed is about 500ﾟC in the composition of (LaNi_5)_<0.8-0.7> (LaNi_<12>B_6)_<0.2-0.3>. The PCT measurements reveal that the amount of absorbed hydorgen in amorphous phase is small, that of crystallized alloys after heat-treatment increases and is around 0.9mass%.(2) Amorphous-formation on La-Ni-B alloys with low B content and its hydrogen absorbing properties :The formation of amorphous phase in the alloys with low B content is studied for the compositional alloys of LaNi_3B_<0.5>M_<0.5>(20at%La-10at%B), LaNi_<3.25>B_<0.25>M_<0.5>(20at%La-5at%B), LaNi_<4.85>B_<0.3>M_<0.5>(15at%La-4.5at%B). Then only LaNi_3B_<0.5>M_<0.5> alloy forms the amorphous phase, which absorbs the hydrogen of 0.6mass%. The rest of alloys such as LaNi_<3.25>B_<0.25>M_<0.5> consists of nearly LaNi_5 single phase, which becomes amorphous phase after absorbing hydrogen. But, LaN_<14.85>B_<0.3>M_<0.5> alloys absorb the hydrogen of around 1 mass% at 2MPa hydrogen pressure for all additional elements. After 30 hydride-dehydride cycle test, these crystallized alloys shows almost no degradation in comparison with LaNi_5 alloys, specially the alloy with Fe addition shows the prevention of pulverization of alloys.