Abstract: Magnetic nanocomposite materials including iron, rare earth elements, boron, refractory metals and cobalt which have favorable magnetic properties and are suitable for making bonded magnets are disclosed. Compositions of the present invention can be of the formula: (N1−yLay)vFe100−v−w−x−zCowMzBx, where M is at least one refractory metal selected from Ti, Zr, Hf, V, Nb, Ta, Cr, Mo and W; v is from about 5 to about 15; w is greater than or equal to 5; x is from about 9 to about 30; y is from about 0.05 to about 0.5; and z is from about 0.1 to about 5. Preferably M is at least Cr. These materials have good magnetic properties and are suitable for use in preparing bonded magnets.

Abstract: Magnetic nanocomposite materials including iron, rare earth elements, boron, refractory metal and, optionally, cobalt are disclosed. Neodymium and lanthanum are preferred rare earth elements. The amounts of Nd, La, B and refractory metal are controlled in order to produce both hard and soft magnetic phases, as well as a refractory metal boride precipitated phase. The refractory metal boride precipitates serve as grain refiners and substantially improve the magnetic properties of the nanocomposite materials. The materials are particularly suitable for making bonded magnets.