Fabrication and structure of rapid solidified Nd-Fe-B thick ribbons

The Nd-Fe-B Ribbons of 0.1-0.4 mm thick were fabricated by using single roll melt spinning in replace of the traditional casting method. The relationship among the technological parameters, the thickness of ribbons and the microstructure is obtained. In order to fabricate the Nd-Fe-B ribbons of 0.25-0.35 mm thick, the optimum technological parameters should be controlled in the following range. The rolling velocity is about l0 m/s, the jet pressure is 0.08-0.10 MPa, and the gap between the roll and the nozzle is (2±0.5) mm. The microstructure of the ribbon of 0.3 mm thick is mainly composed of lamellar Nd₂Fei₄B phase, which grows in the preferred orientation of <410>, and the spacing between the Nd-rich phases is 5 μm. For the ribbon of 0.4 mm thick, the amount of α-Fe is obviously higher than that of Nd₂Fei₄B, and the preferred orientation is <008>. The microstructure of the ribbon of 0.1 mm thick is composed of fine equiaxed grains, but that of the ribbon of 0.4 mm thick, of thick equiaxed grains.