制备工艺对无钴AB_(5-5.6)型合金相结构和电化学性能的影响  

Effect of preparation process on phase structure and electrochemical performance of cobalt-free AB_(5-5.6) alloy

作　　者：孙艳 罗永春[2] SUN Yan;LUO Yongchun(Gansu Province Agricultural Reclamation Secondary School,Lanzhou 730050,Gansu,China;Department of Materials Science and Engineer Lanzhou University of Technology,Lanzhou 730050,Gansu,China)

机构地区：[1]甘肃省农垦中等专业学校,甘肃兰州730050 [2]兰州理工大学材料科学与工程学院,甘肃兰州730050

出　　处：《金属功能材料》2023年第1期85-96,共12页Metallic Functional Materials

摘　　要：用真空电弧熔炼、铜辊快甩(10 m/s)和热处理(1 273 K×15 h)制备稀土系CaCu5型过计量比合金,研究不同制备工艺下,合金La_(0.55)Ce_(0.25)Y_(0.2)(NiFeAlMn)_(5.0-5.6)相结构、微观组织、电化学性能的影响规律。结果表明,在不同的制备工艺下,计量比的增加都不会改变合金的相结构。常规熔铸合金晶粒由粗大的树枝晶和第二相组成;快淬合金都呈现出细小的等轴晶或柱状晶,且抑制了第二相的形成;退火合金使成分均匀化,第二相含量较铸态合金明显减少。合金电化学性能研究表明,不同的制备工艺下,随计量比的增加,合金的放电容量均降低,循环稳定性均提高,高倍率性能均降低。但对同计量比合金而言,循环稳定性依次为退火合金大于快淬合金大于铸态合金,而高倍率性能大小正好相反。综合电化学性能可知,过计量比有利于改善合金的循环稳定性,但会降低合金的动力学性能,所以合适的计量比结合适当的制备工艺可显著提高合金的综合性能。The rare earth CaCu5-type over-measuring ratio alloy is prepared by melting, rapid spinning(10 m/s) and heat treatment(1 273 K×15 h) method to study the influence of different preparation processes on the phase structure, microstructure and electrochemical performance of La_(0.55)Ce_(0.25)Y_(0.2)(NiFeAlMn)_(5.0-5.6)alloy. The results show that the phase structure of the alloy is not changed with the increase of the metering ratio under different preparation process. The cast alloy grain consists of coarse dendrite and the second phase. Fine equiaxed or columnar crystals are present in the rapidly quenched alloys, and the formation of the second phase is inhibited. The composition of annealed alloy is homogenized, and the content of the second phase of annealed alloy is less than that of as-cast alloy.The electrochemical performance of the alloy shows that the discharge capacity of the alloy decreases with the increase of the metering ratio under different preparation processes, and the cyclic stability was improved while the high rate performance was decreased. However, for the same ratio of alloys, the cyclic stability of annealed alloy is greater than that of rapidly quenched alloy than that of cast alloy, while the high rate property is opposite.Based on the electrochemical performance, it can be seen that the over metering ratio is conducive to improving the cycle stability of the alloy, but it will reduce the dynamic performance of the alloy. Therefore, appropriate metering ratio combined with appropriate preparation process can significantly improve the comprehensive performance of the alloy.

关 键 词：无钴AB_(5-5.6)储氢合金 制备过程 微观组织 相结构 电化学性能 

分 类 号：TG139.7[一般工业技术—材料科学与工程]