Amorphous formation and magnetic properties of Nd-Fe-Co-Al alloys by gas flow type levitation process

It is reported that Nd-Fe-Co-Al amorphous alloys have high bulk amorphous formation ability and high coercivity by rapid solidification method. We have examined the undercooling solidification, bulk amorphous formation and high coercivity appearance by using containerless process. In this study, we investigated the undercooling, bulk amorphous formation and magnetic properties for Nd-Fe-Co-Al alloys which are levitated and solidified by using the gas jet flow and high cooling type electromagnetic levitation system. Therefore, the high undercooling degree was 66-152K and the samples formed amorphous phase. The bulk samples, phi 6 mm, sphere, solidified at the cooling rate, about 100 K/s. In addition, the coercivity for Nd65Fe10Co15Al10 sample with bulk amorphous phase, 3.7 kOe, was the highest value in all samples. Also, the thermal stability for Nd65Fe10Co15Al10 sample was carried out by isothermal annealing experiments. The origin of high coercivity may be related to the amorphous phase.