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稀土系储氢合金的成分分析,国外多用ICP-AES法。本文结合我国实际,继LaNi_5、LaNi_(4.5)Cu、LaNi_(4.5)Sn(0.5)之后,提出了LaNi_(4.5)Mn_(0.5)合金中分量的分析方法,方法终点锐敏、快速而简便、结果可靠。 镧、镍、锰离子皆可与EDTA生成配合物,其稳定常数分别为15.50,18.60,13.90。此外,镧与氟离子生产溶度积很小的沉淀,锰与三乙醇胺生成稳定的配合物。因此,在pH5～6的试液中加入过量的EDTA,用偶氮胂Ⅲ作指示剂,用Pb~(2+)溶液滴定过量的EDTA,可得试样中成分的总量,加入NaF后释放出相应的EDTA,可求出镧的含量;
Rare Earth hydrogen storage alloy composition analysis, the foreign multi-purpose ICP-AES method. In this paper, combining with the actual situation of our country, the analytical method of the components in LaNi 4.5 Mn 0.5 alloy is proposed after LaNi 5, LaNi 4.5 Cu and LaNi 4.5 Sn 0.5. The method has the advantages of sharp endpoint, quick and simple method, reliable. Lanthanum, nickel and manganese ions can all form complexes with EDTA, and their stability constants are 15.50, 18.60 and 13.90, respectively. In addition, lanthanum and fluoride ion produce precipitation with a small solubility product, and manganese and triethanolamine generate stable complexes. Therefore, in the pH5 ~ 6 test solution by adding excess EDTA, with arsenazo Ⅲ as an indicator, with Pb ~ (2+) solution titration of excess EDTA, the sample can be obtained in the total amount of ingredients, after the addition of NaF Release the corresponding EDTA, can find the content of lanthanum;