吸铸对2：17型SmCo永磁合金内秉矫顽力的影响

Effect of Suction Casting on Intrinsic Coercivity of 2:17 Type SmCo Alloy

2∶17型Sm(CoFeCuZr)z合金由于居里温度高、磁性能优良、温度系数低等优点被认为是最有希望实现高温应用的一类永磁体。为了解决具有低内秉矫顽力温度系数特征的合金内秉矫顽力不高的问题,本文提出了一种在不改变成分的前提下通过改进制备工艺、优化热处理工艺提高合金室温内秉矫顽力的思路。本文在真空非自耗电弧熔炼炉中采用铜模吸铸法制备了不同尺寸的2∶17型SmCo合金,确定了优化的热处理工艺,并采用永磁测量仪对其磁性能进行表征。研究发现,在不同尺寸吸铸试样中Φ6试样磁性能比较稳定;热处理后其室温内秉矫顽力达到1300 kA.m-1,比相同成分普通铸锭的880 kA.m-1有显著提高。分析认为,吸铸法制备的合金内秉矫顽力的提高与其晶粒细化、取向度提高以及胞状组织的改善有关。

2：17 type Sm （CoFeCuZr）z magnets were the best candidates for high temperature applications due to its high Curie temperature, high intrinsic coercivity （Hci） and low Hci temperature coefficient. The increasing of the z value led to better magnetic properties and higher Hci temperature coefficient in this alloy, and the magnetic property and Hci temperature co-fficient both decreased with the reducing of the z value. In order to solve the problem that the Hci of 2： 17 type SmCo alloy with a low Hei temperature coefficient was not high enough, the suction casting process was used to preparation this alloy. It was found that the Hci of Ф6 alloy rod was remarkably enhanced （16.47 kOe） by using suction casting method and which was much higher than that of the ingot prepared by arcmelting （10 kOe）. The more excellent magnetic property of Ф6 sample than that of the ingot might be due to grain refinement, increasing of orientation degree and improvement of the cellular microstructure caused by preparing process.