Microstructure And Magnetic Properties Of Nanocomposite Nd9.5fe79-Xco5nbxb6.5 (X=0, 1, 2, 3) Permanent Alloys

Nanocomposite Nd9.5Fe79-xCo5NbxB6.5 (x=0, 1, 2, 3) alloys were prepared by melt-spinning at a rate of 18 m/s cooperating with subsequent annealing. The effects of Nb content on microstructure and magnetic properties for the alloys have been studied by XRD, VSM, TEM and 3DAP. The results show that the J(r) firstly increases with the increasing of Nb content from 0.92 T up to 0.94 T at x=1, and then decreases obviously with further Nb addition. The H-i(c) increases monotonically and then increases at a lower rate when the Nb content exceeds 2at%. The (BH)(max) appears to increase from 104 kJ/m(3) at x=0 to a maximum of 120 kJ/m(3) at x=2, and then decreases sharply. An intergranular NbFeB phase with chemical composition near the Nb:Fe:B stoichiometry of 26: 48: 26 between the Nd2Fe14B interfaces is found in Nd9.5Fe77Co5Nb2B6.5 by the 3DAP technique, which provides direct evidence of magnetic properties improvement.