Method for the preparation of alloys of the rare earth metals of the SE.sub. Fe.sub.17-x TM.sub.x N.sub.y type

A method for preparing alloys of Se.sub.2 Fe.sub.17-x TM.sub.x N.sub.y formula wherein SE stands for a rare earth metal, including Y, or a mixture of these metals, while TM stands for Co, Ni, Cu, Zr, Ga, Hf, Ta, Nb, Ti, Si, Al, V, Mo, Cr, Zn or Sn or a mixture of these metals, x=0 to 10, and y=>0 to 5, said alloys having a magnetic anisotropy in the direction of the C axis, comprising the steps of:

• a1) reducing calciothermally a finely divided, homogeneous mixture of components comprising the alloys, at least one of components being present in an oxide form and adjusting the exothermicity of calciothermal reduction by changing the oxide content of the mixture, which corresponds in its composition to the desired alloy, by fulfilling a temperature condition that T.sub.M >T.sub.R .gtoreq.0.9 T.sub.M, wherein T.sub.M being the melting temperature in degrees Kelvin of the intermetallic phase and T.sub.R being the reduction temperature;
• a2) the mixture comprising of components, with the exception of Calcium, having an average particle size of .ltoreq.75 .mu.m;
• a3) tempering the reaction product at the end of the exothermic reaction at a temperature, which is at least 0.7 times the melting temperature T.sub.M of the desired alloy, but is less than the melting temperature T.sub.M, during a period of time adequate for diffusion of the components;
• and
• b) subsequently nitriding the reaction product thus obtained with nitrogen or a mixture of nitrogen and hydrogen or NH.sub.3 in a temperature range between 473.degree. K. and a temperature below the decomposition temperature of the nitride of formula Se.sub.2 Fe.sub.17-x TM.sub.x N.sub.y.