La2Fe14B和Ce2Fe14B合金在快淬和热处理过程中相析出行为的比较

研究了溶体快淬三元La_2Fe_(14)B和Ce_2Fe_(14)B合金的相析出行为和磁性能,对不同快淬速度(10~50 m/s)和不同热处理温度下制备的样品进行了系统分析。结果表明,通过直接快淬,La_2Fe_(14)B合金中不能形成2∶14∶1硬磁相,而Ce_2Fe_(14)B合金可以获得2∶14∶1相。La_2Fe_(14)B合金在10m/s快淬时主要由La和α-Fe相组成,而Ce_2Fe_(14)B合金中2∶14∶1硬磁相在10m/s和20m/s快淬时析出。随着辊速的增加,非晶相逐渐增多并成为主相。在热处理过程中,La_2Fe_(14)B合金析出相以α-Fe和La相为主,并且高温下液态的富La相和α-Fe相可以共存;而Ce_2Fe_(14)B合金中先析出α-Fe,后析出2∶14∶1硬磁相,随后析出相长大。结果还表明,La_2Fe_(14)B比Ce_2Fe_(14)B有更高的非晶居里温度和更低的α-Fe相析出温度。由于硬磁相的析出,Ce_2Fe_(14)B合金可以获得较好的硬磁性能,包括一定的矫顽力。此研究对含La、Ce稀土永磁材料的生产具有一定的指导作用。

Phase Precipitation Behavior of La2Fe14B and Ce2Fe14B Alloys During Melt Spinning and Heat Treatment:a Comparative Study

To understand the structure,phase precipitation behavior and magnetic properties of ternary La2Fe14B and Ce2Fe14B alloys,the effects of wheel speed (10—50 m/s)of melt spinning and heat treatment on these alloys were investigated.The results show that,as for pun alloys,the hard magnetic 2:14:1 phase could not be obtained in La2Fe14B alloys,but it could be formed in Ce2Fe14B alloys.The phases ofα-Fe and La mainly precipitated in La2Fe14B ribbons at 10 m/s.However,the hard magnetic 2:14:1 phase precipitated in Ce2Fe14B ribbons at 10 m/s and 20 m/s.With the increase of wheel speed,the content of amorphous phase in-creased.For annealed La2Fe14B alloys,the results showed that α-Fe and La phases mainly precipitated from the amorphous matrix, and liquid La-rich regions andα-Fe phases could coexist.However,in the annealed Ce2Fe14B alloys,α-Fe phase precipitated first fol-lowed by the appearance of 2:14:1 phase and grain growth.In addition,the amorphous La2Fe14B alloy had higher cure temperature than Ce2Fe14B alloy,and it started to precipitateα-Fe phase at lower temperature.As a result,relatively good hard magnetic proper-ties with a certain coercivity could be obtained in Ce2Fe14B alloys due to the precipitation of hard magnetic 2:14:1 phase.This work will be valuable for exploring the La or Ce based rare earth permanent magnets.