Study On Preparation And Magnetic Properties Of Nd-Fe-Based Bulk Metallic Glass Composite Materials

The purpose of this work is preparing Nd-Fe based amorphous/ nano-crystalline hard magnetic composite materials. Details of the fabrication were studied based on the deeply understanding of current circumstances of Nd-Fe based bulk metallic glass performed at home and abroad.The samples of several different alloy systems, such as Nd60FexCo30-xAl10,Nd60Fe15Co15-xAl10Nix etc, were prepared by copper mold-casting, special copper mold-casting and melt-spinning. The glass forming ability and magnetic property of Nd60FexCo30-xAl10 and Nd90-xFexAl10 system were investigated. After adding Ni and Cu to Nd60Fe15Co15Al10 and Nd60Fe30Al10 respectively, the relationship between glass forming ability and magnetic property were studied. Through annealing, influences of annealing temperature on coercivity of Nd60Fe15Co11Al10Ni4 were also studied.The structure of the samples were characterized by X-ray diffraction (XRD). The crystallization dynamics of the samples were studied by differential scanning calorimetry (DSC). The M-H loops of the samples were tested by vibrating sample magnetometer(VSM).The Nd60FexCo30-xAl10(5≤x≤20) amorphous rods with diameter of 8mm can be prepared by special mold-casting; under the same preparing condition, the magnetic property can be improved through adding Ni to the alloys. The BHMax of the Nd60Fe15Co15-xAl10Nix samples can reach 73.2kGOe. The coercivity of Nd-Fe-Co-Al based samples increased from 3.2kOe to3.7kOe with addition of 2at% Cu. The fully amorphous ribbons prepared by melting-spinning show soft magnetic properties;The obvious crystallization can be observed in the as-cast Nd60Fe15Co15-xAl10Nix samples which showed dual-phase magnetic properties due to the contribution of FeNi and metastable ferromagnetic phase. In addition,The content of Fe had a great effect on the magnetic property ofNd-Fe-Al based amorphous samples prepared by special mold-casting. With the Fe content ranging from 30at% to 40at%, the BHMax can be almost doubled The addition of Ni leads to lower magnetic property,but they are still far better than the Nd-Fe-Co-Al based amorphous samples.