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为了改善La3MgNi14合金的循环寿命,在0.3 MPa氩气气氛及1123、1223、1323 K温度下分别对合金进行了退火处理,处理时间为10 h,同时研究了退火温度对La3MgNi14电极合金的相结构、显微组织及电化学行为的影响。结果表明,退火温度影响合金的相结构,铸态及1123 K温度退火后合金包含LaNi5、(La,Mg)2Ni7主相和少量的LaNi2相,1223 K温度退火有利于合金中(La,Mg)Ni3相的形成,1323 K温度退火后合金主相为LaNi5和(La,Mg)Ni3相。退火后合金的显微组织比铸态合金更加均匀,晶粒尺寸增大。随着退火温度升高,合金的最大放电容量和循环寿命单调增加,高倍率放电性能、损耗角以及极限电流密度增大,充放电电位差和电荷迁移电阻减小。
In order to improve the cycle life of La3MgNi14 alloy, the alloys were annealed under 0.3 MPa argon atmosphere and at 1123, 1223 and 1323 K for 10 h respectively. Meanwhile, the phase structure of La3MgNi14 alloy was studied. Effect of Microstructure and Electrochemical Behavior. The results show that the annealing temperature affects the phase structure of the alloy, and the as - cast and annealed alloys containing LaNi5, (La, Mg) 2Ni7 and a small amount of LaNi2 phase after annealing and annealing at 1223 K are favorable for the formation of (La, Mg) Ni3 phase formation, 1323 K temperature annealed alloy main phase is LaNi5 and (La, Mg) Ni3 phase. After annealing, the microstructure of the alloy is more uniform than the as-cast alloy, and the grain size increases. With the increase of annealing temperature, the maximum discharge capacity and cycle life of the alloy monotonically increase, and the high rate discharge performance, the loss angle and the limiting current density increase, and the charge-discharge potential difference and the charge transfer resistance decrease.