片铸和锭铸Nd-Fe-B合金HDDR磁粉的比较及均质化处理的影响

以成分为Nd_(13.0)Fe_(80.1)B_(6.4)Ga_(0.3)Nb_(0.2)(at%)的速凝合金铸片为原料,采用HDDR工艺制备各向异性钕铁硼磁粉。研究了均质化热处理工艺和HDDR工艺对磁粉性能的影响。结果表明,在1000~1160℃温度范围内,随着均质化热处理温度的升高,磁粉的B_r和(BH)_(max)逐步提高;在0~20h时间范围内,随着均质化热处理时间的延长,磁粉的B_r和(BH)_(max)逐步提高;经由最佳均质化热处理(1160℃×20h)的速凝铸片制备的磁粉,其B_r为1.43T、Hcj为1.30MA/m、(BH)_(max)为352k J/m~3。在均质化热处理与HDDR工艺条件相同的情况下,使用片铸合金和传统锭铸合金制备的粘结磁体相比较,前者的B_r、(BH)_(max)分别高出后者约5%、10%。速凝铸片即使不进行均质化热处理,通过适当调整HDDR工艺参数也能制备出磁性能较佳的各向异性钕铁硼磁粉。

Comparison of strip and ingot casting Nd-Fe-B alloy HDDR magnetic powders and the effects of homogenizing treatment

HDDR-treated anisotropic powders were prepared from strip casting (SC) Nd13.0Fe80.1B6.4Ga0.3Nb0.2 alloy flakes. Effect of homogenization heat treatment process and HDDR process on the magnetic properties were studied. The results show that in temperature range of 1000 to 1160℃, with increasing homogenization heat treatment temperature, Br and (BH)max of the magnetic powder increase; in homogenization heat treatment time range of 0 to 20h, with extending ghomogenization heat treatment time, both magnetic powderBr and (BH)max gradually increase; the powder obtained from the optimally annealed (1160℃×20h) alloy flakes, exhibitsBr of 1.43T,Hcj of 1.30MA/m, and (BH)max of 352kJ/m3. In the same conditions of homogenization heat treatment process and HDDR process, theBr and (BH)max of the bonded magnets from strip casting alloy are 5% and 10% higher than those of magnets from the traditional ingot casting alloy, respectively. Anisotropic Nd-Fe-B powders with excellent good magnetic performance can prepared from cast strip even without homogenization heat treatment by appropriately adjusting HDDR process parameters.