铜辊转速对钕铁硼速凝薄片显微组织及磁体性能的影响

Effect of Copper Roller Wheel Speed on Microstructure of Nd-Fe-B Cast Strip and Property of Corresponding Magnets

采用FMI-I-600-R-C型真空感应熔炼速凝炉在不同的辊速下制备了钕铁硼速凝薄片,并分别制备磁体。通过微观组织对比分析发现,铜辊转速对薄片的微观组织无明显影响,而主要改变了速凝薄片的厚度分布。速凝薄片的显微组织主要与厚度有关:在0.2~0.4 mm范围内薄片主要由主相柱状晶组成,当厚度超过0.4 mm时,在薄片的自由面开始析出α-Fe。通过性能对比发现,当辊速为1.4 m·s^(-1)时,所得磁体的综合性能最优,其中(BH)_(max):43 MGOe,B_r:13.5 kGs,Hci:17.3 kOe,H_k/H_(ci):0.867。

Nd-Fe-B cast strips with different thickness were made by NO. FMI-I-600-R-C vacuum induction melting rapid solidification furnace, and the strips were made into sintered magnets. The results showed that the wheel speed mainly changed the distribution of the cast strips. The mierostructure of the cast strips was related to the thickness ： the cast strips with thickness in the range of 0.2 - 0.4 mm was mainly composed of main phase columnar grain. When the thickness was more than 0.4 mm, α-Fe precipitated in the free side of the strips. The optimum magnetic properties of the sintered magnets made by the cast strips which were obtained at the cooling rate of 1.4 m·s^-1 are as follows： （BH） max： 43M GOe, Br： 13.5 kGs, Hci： 17.3 kOe, Hk/Hci： 0.867.