Study on synthesis and magnetic properties of Nd2Fe14B nanoparticles prepared by hydrothermal method

•The Nd2Fe14B nanoparticles were prepared by the hydrothermal method.•The Nd-Fe-B precursors were synthesized at a lower temperature with a simpler step.•The mean size of the Nd2Fe14B nanoparticles was around 35 nm. It is extremely promising but challenging to synthesize Nd2Fe14B magnetic nanopowders by chemical methods, because of the chemical instability of them. Here, we report an inexpensive and facile bottom-up strategy to synthesize the chemically homogeneous Nd2Fe14B nanoparticles. The Nd-Fe-B precursors were prepared by hydrothermal method using neodymium nitrate hexahydrate, iron nitrate hexahydrate and boric acid as raw materials. Subsequently, the precursors were oxidized by annealing at 800 °C for 2 h. The prepared oxides were mixed with CaH2 and heated to 900 °C under a mixing flow of 5% H2/95% Ar gas. After the reduction- diffusion annealing process, Nd2Fe14B nanoparticles were obtained and washed with water and ethanol. The as-synthesized nanoparticles have a mean size of 35 nm, a saturation magnetization of 107 emu/g and a coercivity of 1.2 kOe.