Research on efficiency of amorphous and nanocrystal line Nd₂Fe₁₄B/α-Fe powder prepared by two milling methods

It is taken for granted that attritor ball mill's efficiency is larger than that of planetary ball mill. However, the true difference between those two methods has not been analysed comparatively. Two milling methods including a planetary ball milling and an attritor ball milling were applied to the milling of Nd₂Fe₁₄B/α-Fe. The effect of different milling methods on microstructure was investigated by X-ray diffraction (XRD), SEM, TEM and AFM. The results show that the grain size of both the Nd₂Fe₁₄B and the α-Fe phase decrease drastically with increasing milling time. After milling for 5h, the as-milled material in the attritor ball mill is comprised of amorphous Nd₂Fe₁₄B and α-Fe nanocomposite phase with 10nm grains size. Milling energy of the attritor ball mill is higher than that of the planetary ball mill. Therefore, the milling method of the attritor ball mill not only increases the productivity but also lays the foundation for preparing nanocomposite Nd₂Fe₁₄B/α-Fe magnetic material.