Increasing the cooling velocity and additions of nb and zr can refine the a - fe dendrites in as - cast alloys , decrease the amount of a - fe phase after homogenization treatment . as a result , the magnetic . properties were improved 提高铸锭的凝固速度及添加nb和zr可以促进铸态合金内- fe相的晶粒细化及均匀分布,减少均匀后残留的- fe相,提高均匀化的效率和质量,从而提高磁体的矫顽力。