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应用铸造及快淬工艺制备了La0.7Mg0.3Co0.45Ni2.55-xCux(x=0,0.1,0.2,0.3,0.4)贮氢电极合金,研究了快淬工艺对合金微观结构及电化学性能的影响。XRD,SEM及TEM的分析结果表明,铸态及快淬态合金具有多相结构,包括(La,Mg)Ni3相,LaNi5相以及LaNi2相。快淬对合金的相组成没有明显影响,但显著地改变了合金的相丰度。快淬还显著地改善合金的成分均匀性,并使合金的晶粒明显细化。电化学测试的结果表明,快淬大幅度提高合金的电化学循环稳定性,但使合金的放电容量和活化性能下降。快淬对合金的放电电压特性具有明显的影响,当淬速大于15m/s时,快淬降低合金的放电电压,并使放电平台的斜率明显增大。
La0.7Mg0.3Co0.45Ni2.55-xCux (x = 0,0.1,0.2,0.3,0.4) hydrogen storage electrode alloy was prepared by casting and rapid quenching. The effects of quenching process on the microstructure and electrochemical properties of the alloy were studied. Impact. The results of XRD, SEM and TEM show that the as-cast and quenched alloys have multi-phase structure including (La, Mg) Ni3 phase, LaNi5 phase and LaNi2 phase. Quenching has no significant effect on the phase composition of the alloy, but significantly changes the phase abundance of the alloy. Quenching also significantly improves the compositional uniformity of the alloy and allows the grain of the alloy to be significantly refined. The results of electrochemical tests show that quenching greatly improves the electrochemical cycling stability of the alloy, but decreases the discharge capacity and activation performance of the alloy. Quenching has a significant effect on the discharge voltage characteristics of the alloy. When the quenching speed is more than 15m / s, quenching reduces the discharge voltage of the alloy and increases the slope of the discharge platform obviously.