A simple and easy method with high accuracy has been introduced for the determination of hydrogen absorption properties of alloys, such as hydrogen absorption capacity , paressure-composition isotherms and thermodynamic parameters ΔH and ΔS.The apparatus is described in details. The equilibrium data can be obtained under hydrogen pressure of 16-0.0001MPa and in the range of temperature -196-+500 ℃.
Pressure composition isotherms, crystal structures and electrochemical capacities of MmB5 alloy-hydrogen systems have been investigated, where Mm represents La-rich mischmetals and B5 take a composition of Ni3.8Co0.5Mn0.4Al0.3. All these multicomponent alloys belong to CaCu5-type hexagonal crystal structuxe. The volume of unit cell (or say,the interstitial hole size) becomes larger with increasing of La content and decreasing of Ce content in Mm. The larger interstitial hole leads to a decrease of dissociation pressure of their hydride, hence improves the stability of MmB5H6 and the electrochendcal capacity of the MmB5 alloy. The expansion ratio of the MmB5 for hydrogen absorption was obviously smaner than that of LaNi5 alloy. For MmB5 alloy, especially with high content of La in Mm, a lot of properties for the application in MH/Ni battery, such as against pulverization, long cycle lifetime etc can be promoted.
At room temperature, LaNi5-based multicomponent alloys can easily react with Cu2+aqueous solution (such as the CuSO4 solution). The elements La, Ni, Co, Mn and Al in the alloyswere oxidized to form their ions correspondingly, and the Cu2+ ion was reduced to precipitate asmetal copper.
1997年7月13～18日金属—氢体系戈登研讨会(Gordon Research Conferences on Metals-Hydrogen Systems)在美国新罕什布尔州的新英格兰学院举办,有135人出席会议,其中美国占41%,日、英、法、德等国占34%. 戈登研讨会包括上百个分会,金属—氢体系是其中之一。下届金属—氢体系研讨会将于1999年仍在新英格兰学院召开。
