Exchange coupled Nd₂Fe₁₄B/α-Fe nanocomposite by novel autocombustion-reduction diffusion synthesis

We report the synthesis of magnetic Nd₂Fe₁₄B-α-Fe powders synthesized by a novel process of glycine nitrate auto combustion followed by reduction diffusion. Glycine nitrate based combustion of mixed metal nitrates of Nd, Fe and B is carried out to obtain homogeneously mixed oxide powders of Nd, Fe and B. The reduced Nd-Fe-B powders obtained using this route exhibited coercivity of 5000 Oe and energy product of 3.98 MGOe. X-ray diffraction studies confirmed the presence of the tetragonal Nd₂Fe₁₄B phase. The SEM micrographs showed agglomerated grains with powder size of ~500 nm. TEM studies showed that the individual particle size was in the range of 5 to 20 nm. This is the first report of this synthesis protocol for Nd₂Fe₁₄B; it offers several advantages such as ease of elemental substitution, ease of obtaining nanoparticles and the relatively low reduction temperatures required for synthesis.