Surface quality, microstructure and magnetic properties of Nd2(Fe,Zr,Co)14B/α-Fe alloys prepared by different melt-spinning equipments

The effects of melt-spinning equipments on the surface quality, microstructure and magnetic properties of Nd2(Fe,Zr,Co)14B/α-Fe magnets have been studied. The ribbons prepared by the induction-melt spurt-spinning equipment have smooth surfaces and uniform thickness. However, the ribbons prepared by the arc-melt overflow-spinning equipment have rough surfaces and inhomogeneous thickness, which makes the cooling rate nonuniform through the thickness of ribbons and causes the occurrence of coarse grains. The ribbons prepared by induction-melt spurt-spinning equipment show better magnetic properties than the ribbons prepared by arc-melt overflow-spinning equipment, even using the same alloy composition. By properly increasing the Zr content, the glass forming ability of alloy is improved, which can lessen the detrimental effect of cooling rate fluctuation, thus enhancing the magnetic properties of ribbons prepared by the arc-melt overflow-spinning equipment.