Fabrication and Phase Evolution of Pr2Fe14C-based Magnetic Nanoparticles Prepared by Mechanochemical Method

•Nano-sized Pr2Fe14C-based magnetic particles were prepared by a facile mechanochemical method.•H2 and C were introduced by the decomposition of heptane during the high-energy ball milling process.•The two-step recombination reaction during the annealing process was discovered and discussed.•The addition of boron promoted the formation of Pr2Fe14C phase and suppressed soft magnetic products.