热处理对双合金工艺制备的(Nd,Tb)-Fe-B烧结磁体矫顽力的影响

Effect of heat treatment on coercivity of Nd-Fe-B sintered magnets prepared by dual alloy process

为了在降低重稀土用量的情况下进一步提高磁体矫顽力,应用双合金工艺将主合金粉与辅合金粉按7.5:2.5比例混合制备出双合金Nd-Fe-B烧结磁体。探究了回火工艺对稀土双合金磁体矫顽力的影响,并通过扫描电镜表征了热处理对合金微观结构和组分分布的影响。结果发现,在特定的烧结温度和回火下,合金主相能分布更加均匀,且在其周围的含重稀土相趋于形成薄的壳层结构。该实验方案在保证磁能积基本不降低的前提下通过特定的烧结和时效等热处理工艺有效提高了磁体矫顽力。通过优化热处理方式,最后得到矫顽力为18.57 kOe、磁能积为48.53 MGOe的高性能磁体。

In order to improve the coercivity of the magnet while reducing the amount of heavy rare earths,the Nd-Fe-B bi-alloy sintered magnet was prepared by mixing the main alloy powder and the auxiliary alloy powder in a ratio of 7.5:2.5 by using the double alloy process.The influence of tempering process on the coercivity of rare earth double alloy magnets was explored,and the effect of heat treatment on the microstructure and component distribution of the alloy was characterized by SEM.The results show that the distribution of the main phase energy is more uniform and the heavy rare earth phases around the alloy tend to form a thin shell structure at a specific sintering temperature and tempering.In our experiment scheme,the coercive force of the magnet is effectively increased by special heat treatment process such as sintering and aging,while the magnetic energy product is not reduced.A high performance magnet with coercive force of 18.48 kOe and magnetic energy product of 48.53 MGOe was obtained by optimizing the heat treatment method.